Let me view Bill`s NEW 2016 Version of His A+ Course Notes

Let me view Bill`s NEW 2016 Version of His A+ Course Notes
PREPARING FOR A+ CERTIFICATION: 2016 EDITION
A COURSE IN PC HARDWARE, SOFTWARE, MAINTENANCE AND REPAIR
BY WILLIAM A. LLOYD
ENGINEERING INSTRUCTOR,
PRINCE GEORGE'S COMMUNITY COLLEGE,
COPYRIGHT, WILLIAM A. LLOYD, 2016
LAST REVISED: MAY 16, 2016
Reproduction of these materials is prohibited
without the express written consent of the author.
Email Address: LLOYDWA@pgcc.edu
Website Address: http://academic.pgcc.edu/~wlloyd/rta
Table of Contents
Chapter 1. Overview
Chapter 2. Overview of Basic Hardware Parts
Chapter 3. Overview of POST, CMOS Setup Programs and Error Codes
Chapter 4. Procedures for Testing Equipment
Chapter 5. Procedures for Installing Components
Chapter 6. Troubleshooting Guidelines
Chapter 7. Building a PC from Scratch
Chapter 8. Printers
Chapter 9. Laptops and Tablet Computers
Chapter 10. Power Conditioning with UPSes and Surge Suppressors
Chapter 11. Overview of Windows, Linux, Macintosh and Virtual Operating Systems
Chapter 12. Installing Application Software and Operating Systems
Chapter 13. Viruses, Spyware/Malware, Encryption and Data Security
Chapter 14. Local Area and Dial-Up Networking
Chapter 15. Mobile /Tablet Operating Systems
Chapter 16. Glossary of Terms
Chapter 17. Map of A+ Essentials Exam Objectives (220-801)
Chapter 18. Map of A+ IT Specialist Exam Objectives (220-802)
Chapter 19. Map of A+ Essentials Exam Objectives (220-901)
Chapter 20. Map of A+ IT Specialist Exam Objectives (220-902)
Recommended texts and preparation software
What is Research Technology Associates?
Guidelines for Obtaining Equipment from Research Technology Associates
Guidelines for Donating Equipment to Research Technology Associates
3
6
52
66
79
89
93
100
106
111
114
168
180
201
266
273
347
360
373
401
419
420
421
422
APPENDIX A: List of CPU Socket Types from the 80486-class CPU
to Date (Revised April 2013)
424
APPENDIX B: Practical Computer Repair Sessions at the
MarketPro Computer Shows
427
APPENDIX C: Repair Service Policies for RTA and Computer Shows
(Revised May 2013)
432
APPENDIX D: Using Norton Ghost to Image a Hard Drive
440
APPENDIX E: An Overview of Linux Operating Systems
444
APPENDIX F: Standard Repair Protocols for RTA Help Desk Technicians
448
APPENDIX G: Overview of Windows 10
454
Preparing
for A+ Certification: 2016 Edition
A Coursebook in PC Hardware, Maintenance & Repair
Page 2
Copyright, 2016
William A. Lloyd
Chapter 1. Introduction to A+ Certification
A+ Certification is a testing program that certifies the competency of entry-level (6 months experience)
computer service technicians. It is sponsored by CompTIA, the Computing Technical Industry
Association. The A+ test contains situational and identification types of questions. All of the questions on
the test are multiple choice, most with only one correct answer for each question. The test covers a broad
range of hardware and software technologies, but is not bound to any vendor-specific products.
The A+ certification program is backed by major computer hardware and software vendors, distributors,
resellers and publications. A+ certification signifies that the certified individual possesses the knowledge
and skills essential for a successful entry-level (6 months experience) computer service technician, as
defined by experts from companies from across the industry. A+ certification is recognized worldwide.
Who may take the certification tests?
A+ Certification is open to anyone. The A+ exam is targeted for entry-level computer service technicians
with at least 6 months on-the-job experience (or equivalent training). No specific requirements are
necessary, except for payment of the fee. You can contact CompTIA by phone at 1/630-678-8300.
When you call to register for the test, please have your Social Security Number, a major credit card
number, and your ZIP Code available. You will be told over the phone of the nearest locations available
for you to take the test. The test is offered at all times of the day, night and weekends. You also can
purchase the vouchers needed to take the A+ examination online at:
https://store.comptia.org/default.aspx .
There are two sections of the examination: the Essentials exam, and the IT Specialist exam. Each exam
determines your competency with aspects of PC maintenance, repair, operation and troubleshooting.
You may take the Essentials and IT Specialist exams together, or separately. Once you have taken one
of the tests, you have thirty (30) days to take and pass the other exam in order to become certified.
The test objectives for these two examinations are found in Chapters 17 - 20 of this book. Chapters 17
and 18 cover the 220-801 and 802 examinations, and Chapters 19 and 20 cover the 220-901 and 902
exams. The 220-801 AND 802 examinations will no longer be offered after June 30, 2016.
The A+ test is available throughout the world in a variety of languages (Spanish, French, German, and
Japanese). If you have any questions, please call CompTIA Certification Customer Service at (630)
268-1818. Also, it is CompTIA's policy to make reasonable accommodations for individuals with
disabilities who live in the United States. If you need special accommodations, please contact your test
vendor 30 days before scheduling your exam.
Purpose of this book
This book is intended to prepare the reader to take and pass the A+ certification examination. No
previous knowledge of computers is required, but a working knowledge of how to use an IBM-compatible
PC and/or an Apple Macintosh is helpful. The textbook will endeavor to take complex technical concepts
and explain them in the simplest manner possible. Visuals and graphic examples will also be included to
make concepts and objects easy to visualize and understand.
Disclaimer: all copyright references to name-brand or corporately-branded products within this text (i.e.,
Microsoft Windows) belong to and are the property of the corporations which own them. Definitions and
descriptions of content found in the text are taken from personal experience, and from trusted
information sources, such as manufacturers’ technical support sites.
Preparing
for A+ Certification: 2016 Edition
A Coursebook in PC Hardware, Maintenance & Repair
Page 3
Copyright, 2016
William A. Lloyd
Course Reference DVD Disk
This course book is one part of a DVD-ROM course disk made available to my students. The disk also
holds a variety of open-source software packages, utilities and helpful literature that will enable the
student to build and develop the skills needed to become a successful computer repair technician.
Installers for the following applications are provided on this disk:


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







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


AVG antivirus application (32-bit and 64-bit versions)
MalwareBytes anti-malware application
CCleaner disk clean-up application
Recuva file recovery application
Mozilla Firefox browser installer
Norton and McAfee Uninstaller applications
FileZilla FTP transfer application
Defraggler disk defragmenter
Imgburn optical disk creator application
VLC media player application
Internet Explorer 11 installer
Adobe Flash installers for your browsers
Windows Service Packs for Windows Vista and Windows 7
A variety of other repair and configuration utilities
Copies of videos from our recent service missions to schools in Tanzania and South Africa
The instructor will provide you with a copy of this disk on the first day of class.
We ask for a $20.00 contribution to our non-profit organization, Research Technology Associates, to
defray the cost of duplicating the disks and developing this resource for your use.
Course Diagnostic DVD Disk
As an aid to your learning process, and to assist you in diagnosing and troubleshooting problems with
PCs and laptops, we will provide you with a bootable diagnostic DVD application developed and compiled
by my son, Matthew Lloyd.
The Parted Magic application provides a number of applications that will help you to:










Test hard drives for proper operation using the drive controller’s built-in diagnostics
Create, delete or resize partitions on a hard disk
Transfer data safely from a failing/virus-infected hard drive to a USB flash drive or optical media
Check the temperature sensors in a PC or laptop to determine overheating conditions
Test the memory in a PC or laptop for defects and problems
Change or remove a password on a Windows-based operating system
Use the AVG Rescue Disk to clean viruses off a PC or laptop
Clone a hard disk using the Clonezilla application
Get a summary of detected equipment in a PC or laptop
Explore the Ubuntu or Knoppix Linux operating systems
The applications on this disk are open-source, which means that they can be copied and shared freely
with others. The DVD uses Linux as its operating system, so it will work whether the computer’s operating
system is in working order or not. You will boot the computer to the optical (DVD) drive, rather than to the
hard disk, to launch and use this diagnostic program.
Preparing
for A+ Certification: 2016 Edition
A Coursebook in PC Hardware, Maintenance & Repair
Page 4
Copyright, 2016
William A. Lloyd
This diagnostic disk is one of the best of its kind, and we are happy to provide it to you during the course.
We will make it available to you several weeks into the course, when you are trained sufficiently to
understand how to use it and view the results.
We ask that you make a $20.00 contribution towards the cost of providing you with this resource.
Windows Driver DVD Disk
We also will provide you with a DVD that contains literally thousands of device drivers on the disk. This
will assist you in the event you need to install a device driver or update a driver that is defective. The disk
has drivers for Windows XP, Windows Vista and Windows 7.
We also ask that you make a $10.00 contribution towards the cost of providing you with this resource.
USB flash drive
We require you to obtain at least one 16GB USB flash drive for use in the lab sections of the course. We
will provide you with additional open-source utility programs that you can use in the lab portions of the
class.
You can purchase a USB flash drive from Staples, Office Depot, MicroCenter, Newegg, or any number of
local retailers. A 16GB flash drive should cost no more than $20.00.
Required tools for the course
The toolkit you need for this course should be simple, and cost less than $20.00. It needs to include at
least the following things:
-
Phillips and flat blade screwdrivers (small and medium size)
A 3-claw part grabber
A chip inserter and chip extractor
A TORX head screwdriver
A 1/4" and 3/16" nut driver
Perhaps a container to hold small parts and screws
Things you do NOT need include:
-
A soldering gun
Magnetic tools
Drills
If you have a small voltmeter, that's good; it will be useful in some instances, and you need to know how
to use one for the A+ exam. We have voltmeters in the lab, so you do not have to run out and buy one.
You can buy such a toolkit in places like:
NOTE:
Sam's Club
MicroCenter
-
Best Buy
Office Depot
-
Newegg
Staples
-
Radio Shack
PC Shows
I share NO financial stake in any of the above-mentioned companies. I simply give them as
sources other students and colleagues have used in the past to find decent toolkits for our
courses.
Preparing
for A+ Certification: 2016 Edition
A Coursebook in PC Hardware, Maintenance & Repair
Page 5
Copyright, 2016
William A. Lloyd
Chapter 2. Overview of Basic Hardware Parts
There are a number of different parts inside the typical PC. Each part looks different, and each serves a
specific purpose. In this section of the text, we will illustrate and describe all of the different parts within a
PC.
Central Processing Units (CPUs)
The Central Processing Unit (CPU) chip is the heart of the computer and its ability to process data and
manage tasks within the entire computer.
There are MANY types of CPU chips found on motherboards. This list gives a history of some of the types
of CPU chips that are (or have been) installed on different motherboards over the past 20 years.
Older types of CPUs
INTEL CPU TYPES AND SPECIFICATIONS
CPU TYPE
INTERNAL MATH
CO-PROCESSOR
INTERNAL
REGISTER
DATA BUS
WIDTH
MEMORY
ADDRESSING
MAX. RAM
REGOGNIZED
8088
No
16-bit
8-bit
20-bit
1MB
8086
No
16-bit
16-bit
20-bit
1MB
80286
No
16-bit
16-bit
24-bit
16MB
80386SX/SL
No
32-bit
16-bit
24-bit
16MB
80386DX
No
32-bit
32-bit
32-bit
4GB
80486SX
No
32-bit
32-bit
32-bit
4GB
80486SX2
No
32-bit
32-bit
32-bit
4GB
80487SX
Yes
32-bit
32-bit
32-bit
4GB
80486DX/SL
Yes
32-bit
32-bit
32-bit
4GB
80486DX2
Yes
32-bit
32-bit
32-bit
4GB
80486DX4
Yes
32-bit
32-bit
32-bit
4GB
Pentium 60/66
Yes
32-bit
64-bit
32-bit
4GB
Pentium
75-200
Yes
32-bit
64-bit
32-bit
4GB
Pentium MMX
Yes
32-bit
64-bit
32-bit
4GB
Pentium Pro
Yes
32-bit
64-bit
36-bit
64GB
Pentium II
MMX
Yes
32-bit
64-bit
36-bit
64GB
Pentium II
Celeron
Yes
32-bit
64-bit
36-bit
64GB
Pentium II
Yes
32-bit
64-bit
36-bit
64GB
Preparing
for A+ Certification: 2016 Edition
A Coursebook in PC Hardware, Maintenance & Repair
Page 6
Copyright, 2016
William A. Lloyd
CPU TYPE
INTERNAL MATH
CO-PROCESSOR INTERNAL
REGISTER DATA BUS
WIDTH MEMORY
ADDRESSING MAX. RAM
REGOGNIZED Pentium III
Yes
32-bit
64-bit
36-bit
64GB
Pentium 4
Yes
32-bit
64-bit
36-bit
64GB
AM486DX4-1
00, 120
Yes
32-bit
32-bit
32-bit
4GB
AM5x86
Yes
32-bit
32-bit
32-bit
4GB
K6-166-300
MMX
Yes
32-bit
64-bit
32-bit
64GB
K6-350 - 500
Yes
32-bit
64-bit
32-bit
64GB
Athlon
Yes
32-bit
64-bit
36-bit
64GB
Duron
Yes
32-bit
64-bit
36-bit
64GB
Thunderbird
Yes
32-bit
64-bit
36-bit
64GB
6x86-PR120 200
Yes
32-bit
64-bit
36-bit
64GB
6x86MX-PR1
66 - PR 233
Yes
32-bit
64-bit
36-bit
64GB
AMD CPU TYPES
CYRIX CPU TYPES
Newer types of CPUs
For an exhaustive list of current (and obsolete) CPU types, visit the Intel corporation website
(http://www.intel.com ) or the AMD corporation website ( http://www.amd.com ).
Below is a picture of a typical CPU chip.
For the A+ examination, you will need to be able to answer the following kinds of questions:

What are the major types of CPUs that have been used historically in PCs, and how do they differ?
Preparing for A+ Certification: 2016 Edition
A Coursebook in PC Hardware, Maintenance & Repair
Page 7
Copyright, 2016
William A. Lloyd
Hyperthreading CPUs
Hyperthreading is a technology developed by Intel that enables multithreaded software applications to
execute threads in parallel on a single multi-core processor instead of processing threads in a linear
fashion. Older systems took advantage of dual-processing threading in software by splitting instructions
into multiple streams so that more than one processor could act upon them at once.
Multiple-core CPUs
Current technology processor chips now are being designed so that they contain two or more full-blown
CPU units into one single chip. Typical Intel and AMD CPUs will have between 4 and 8 cores.
Dual-core refers to a CPU that includes two complete execution cores per physical processor. It has
combined two processors and their caches and cache controllers onto a single integrated circuit (silicon
chip). Dual-core processors are well-suited for multitasking environments because there are two
complete execution cores instead of one, each with an independent interface to the front-side bus. Since
each core has its own cache, the operating system has sufficient resources to handle most compute
intensive tasks in parallel.
Multi-core is similar to dual-core in that it is an expansion to the dual-core technology which allows for
more than two separate processors. For example, an Intel i7 CPU will have 8 cores. So why didn’t they
call it an i8 CPU …
On-chip (Level 1) and external (Level 2) cache
A memory cache, sometimes called a cache store or RAM cache, is a portion of memory made of
high-speed static RAM (SRAM) instead of the slower and cheaper dynamic RAM (DRAM) used for main
memory. Memory caching is effective because most programs access the same data or instructions over
and over. By keeping as much of this information as possible in SRAM, the computer avoids accessing
the slower DRAM.
Some memory caches are built into the architecture of microprocessors. The Intel 80486 microprocessor,
for example, contains an 8K memory cache, and the Pentium has a 16K cache. Such internal caches are
often called Level 1 (L1) caches. Most modern PCs also come with external cache memory on the system
board, called Level 2 (L2) caches. These caches sit between the CPU and the DRAM. Like L1 caches, L2
caches are composed of SRAM but they are larger in size (512KB to 2MB).
32bit vs. 64 bit processors (and operating systems)
32-bit refers to the number of bits (the smallest unit of information on a machine) that can be processed or
transmitted in parallel, or the number of bits used for single element in a data format. The term when used
in conjunction with a microprocessor indicates the width of the registers; a special high-speed storage
area within the CPU. A 32-bit microprocessor can process data and memory addresses that are
represented by 32 bits, and has a memory addressing limit of 4 gigabytes (4GB).
64-bit therefore refers to a processor with registers that store 64-bit numbers. A generalization would be
to suggest that 64-bit architecture would double the amount of data a CPU can process per clock cycle.
Users would note a performance increase because a 64-bit CPU can handle more memory and larger
files. One of the most attractive features of 64-bit processors is the amount of memory the system can
support. 64-bit architecture will allow systems to address up to 1 terabyte (1000GB) of memory. The
primary reason to use a 64-bit operating system is to accommodate a PC that has more than 4GB of
RAM available on the system.
Preparing
for A+ Certification: 2016 Edition
A Coursebook in PC Hardware, Maintenance & Repair
Page 8
Copyright, 2016
William A. Lloyd
With 32-bit desktop systems, you only can only address up to 4GB of RAM (provided your motherboard
that can handle that much RAM), which is split between the applications and the operating system (OS).
Some desktop computers today do not even have 4GB of memory installed, and most small business
and home desktop computer software applications do not require that much memory either. As more
complex software and 3D games become available however, we now can see this become a limitation.
For the average home user, this issue may not create an unusual hardship.
Unfortunately, most benefits of a 64-bit CPU will go unnoticed without the key components of a 64-bit
operating system and 64-bit software and drivers which are able to take advantage of 64-bit processor
features. For the average home computer user, 32-bit operating systems are more than adequate for
typical computing tasks.
When making the transition from 32-bit to 64-bit desktop PCs, users will not actually see Web browsers
and word processing programs run faster. Benefits of 64-bit processors would be seen with more
demanding applications such as video encoding, scientific research, searching massive databases; tasks
where being able to load massive amounts of data into the system's memory is required.
While a discussion of 64-bit architecture may make one think this is a new technology, 64-bit computing
has been used for many years in supercomputing and database management systems. Many
companies and organizations with the need to access huge amounts of data have already made the
transition to using 64-bit servers, since a 64-bit server can support a greater number of larger files and
could effectively load large enterprise databases to into memory allowing for faster searches and data
retrieval.
Additionally, using a 64-bit server means organizations can support more simultaneous users on each
server potentially removing the need for extra hardware, as one 64-bit server could replace the use of
several 32-bit servers on a network.
It is in scientific and data management industries where the limitations of the 4GB memory of a 32-bit
system have been reached and the need for 64-bit processing becomes apparent. Some of the major
software developers in the database management systems business, such as Oracle and SQL Server, to
name just two, offer 64-bit versions of their database management systems.
While 64-bit servers were once used only by those organizations with massive amounts of data and big
budgets, 64-bit enabled systems are widely found in the mainstream market. It is only a matter of time until
64-bit software and retail OS packages become the de facto standard, and 32-bit computing will become
somewhat obsolete.
Virtualization Support
Running multiple operating systems on a computer is becoming a more common occurrence in the
business community, especially with the advent of teleworking solutions. You can accomplish this by
installing the operating system to a separate hard disk partition or as a virtual machine. Installing an
operating system as a virtual machine is more advantageous because you don’t have to constantly
restart your computer to access the other OS. Citrix and VMware are the major providers of virtualized
operating system environments.
However in order to create a virtual machine, your processor must support virtualization. Fortunately,
there are many tools (available from Intel and AMD) that enable you to check if your CPU or processor
supports hardware virtualization. Virtualization at a purely software level is becoming more obsolete,
with the advent of multiple-core processors.
Preparing
for A+ Certification: 2016 Edition
A Coursebook in PC Hardware, Maintenance & Repair
Page 9
Copyright, 2016
William A. Lloyd
Motherboards and Bus Connections
Motherboards (also called system boards or mainboards)
The motherboard (or system board) is the main board, or the heart of the computer. A motherboard (or
mainboard) is a multi-layered, precision-made printed circuit board that provides the connectivity
between the many components of a Personal Computer (PC). These connections (commonly referred to
as the “Bus”) provide the required paths for data flow, programmatic information flow and power to the
different components of a PC.
The central processor chip (CPU) is installed into a socket on the motherboard. All of the adapter cards
(like a video card, a modem, or a sound card) plug into the motherboard. It is the largest single board in
the computer.
Bus connections on the motherboard
There are a number of slots on the typical motherboard that can be used to install a variety of adapter
cards, such as video cards, sound cards and modems, into your PC. These slots are called bus
connections. These connections are not keyed to any specific device, so you can place an adapter card
into any of the appropriate type of bus connector slots on the motherboard.
There are several major types of bus connectors, all of which are described on the following pages:
Peripheral Component Interconnect (PCI)
With the introduction of the Pentium processor, Intel took the lead in developing a new type of bus
connector that would be appropriate for the newer classes of CPUs and the increased processing speeds
that would be realized on newer motherboards. The PCI bus connector actually taps into the system bus,
rather than tapping into the processor bus (as does the VESA Local Bus connector).
Information on the PCI bus travels at a speed of 132 megabytes per second, which is a dramatic increase
in throughput speed. It also has the ability to handle 32-bit and 64-bit data transfers. PCI bus connections
have become the de facto standard for current technology motherboards.
Preparing
for A+ Certification: 2016 Edition
A Coursebook in PC Hardware, Maintenance & Repair
Page 10
Copyright, 2016
William A. Lloyd
This type of bus connector is white in color, and looks like what is shown in the picture below.
Accelerated Graphics Port (AGP)
The Accelerated Graphics Port (AGP) is a special type of high-speed video bus slot that is used
exclusively for high-end video cards. It has the ability to transfer 32 bits of data at 66MHz speed, with up
to a clock multiplier of up to four times. At that rate of speed, an AGP connection can transfer 1,066MB of
data per second. AGP ports also give a direct connection to the system RAM, thus reducing the need for
large sums of video memory. AGP ports are appropriate for high speed rendering of images, 3-D video,
and other types of high speed video production.
This type of bus connector is brown in color, and looks like what is shown in the picture below.
AGP bus connectors now are being replaced by PCI-Express bus connectors, which are discussed in
more detail below.
PCI-Express (PCI-E) and PCI-X bus connections
PCI-Express (PCI-E) is an I/O interconnect bus standard (which includes a protocol and a layered
architecture) that expands on and doubles the data transfer rates of original PCI. PCI Express is a
two-way, serial connection that carries data in packets along two pairs of point-to-point data lanes,
compared to the single parallel data bus of traditional PCI that routes data at a set rate. Initial bit rates for
PCI Express reach 2.5Gb/s per lane direction, which equate to data transfer rates of approximately
200MB/s. PCI Express was developed so that high-speed interconnects such as 1394b, USB 2.0,
InfiniBand and Gigabit Ethernet would have an I/O architecture suitable for their transfer high speeds.
PCI Express, also known as 3GIO (for third-generation input/output) is compatible with existing PCI
systems.
By comparison, PCI-X uses a parallel interconnect along a bus that is shared with other PCI-X devices,
just like PCI. In fact, PCI-X is best thought of as "PCI-eX tended", as it is simply an extension of the legacy
PCI 32-bit format, with which it is backward-compatible. It differs mainly in the fact that the bus is now
64-bits wide, and runs at higher frequencies (now up to 533MHz, compared to 66MHz - the fastest PCI
frequency).
PCI-Express, on the other hand, uses a serial interconnect along a switched bus dedicated exclusively to
that slot. In this respect, and most others, it uses radically new architecture, having little to do with old
PCI. Furthermore, PCI-Express has the unique capability of multiplying up individual data "lanes", to
produce aggregate interconnects that can deliver up to 16 times the bandwidth of a single lane. This is
why you will always see PCI-Express slots referred to as "PCI-Express*4" or "PCI-Express*16" etc.
Preparing
for A+ Certification: 2016 Edition
A Coursebook in PC Hardware, Maintenance & Repair
Page 11
Copyright, 2016
William A. Lloyd
The standard PCI, PCI-X, PCIe x1 and PCI3 x16 bus connectors are shown in the images below:
Mini PCI
Mini PCI is a subset of the PCI interface that uses a significantly smaller card form factor. Supporting only 3.3 volts
and 32 bits of the PCI specification, Mini PCI was designed for peripherals such as network adapters in laptops, but
also is used in DVD players, HDTVs and other devices.
An example of a Mini PCI laptop network adapter card is shown below:
For the A+ examination, you will need to be able to answer the following kinds of questions:

What are the major types of bus connectors found on PC motherboards, and how do they differ?
Preparing
for A+ Certification: 2016 Edition
A Coursebook in PC Hardware, Maintenance & Repair
Page 12
Copyright, 2016
William A. Lloyd
CPU socket types
There are a variety of types of sockets on current-technology motherboards that allow the user to install
differing types of CPU chips. Having a unique CPU socket type ensured that only the proper type of CPU
chip was installed on the system board.
Here is a chart that lists of some CPU socket types that have been used over the years:
Pin
Count
Release
Date
Socket 0
168
1989
Socket 1
169
NA
486 DX486 DX2486
SX486 SX2
Socket 2
238
NA
486 DX486 DX2486
SX486 SX2 Pentium
Overdrive
Socket 3
237
NA
486 DX486 DX2486
DX4486 SX486 SX2
Pentium Overdrive5x86
Socket 4
273
Mar-93
Pentium-60 and
Pentium-66
Socket 5
320
Mar-94
Pentium-75 to Pentium120
Socket 6
235
never
released
486 DX486 DX2486
DX4486 SX486 SX2
Pentium Overdrive5x86
Socket 7
321
Jun-95
Pentium-75 to Pentium200 Pentium
MMXK5K66x
866x86MXMII
Socket Super 7
321
May-98
K6-2K6-III
Slot 1(SC242)
242
May-97
Pentium II Pentium III
(Cartridge) Celeron
SEPP (Cartridge)
Socket 370
370
Aug-98
Celeron (Socket 370)
Pentium III FC-PGA
Cyrix IIIC3
Socket 423(PGA423)
423
Nov-00
Pentium 4 (Socket 423)
Socket 463
463
1994
Socket
Socket 478 (mPGA478B)
LGA775(Socket T)
478
775
Preparing
for A+ Certification: 2016 Edition
A Coursebook in PC Hardware, Maintenance & Repair
Compatible CPUs
486 DX
Nx586
Aug-01
Pentium 4 (Socket 478)
Celeron (Socket 478)
Celeron D (Socket 478)
Pentium 4 Extreme
Edition (Socket 478)
Aug-04
Pentium 4 (LGA775)
Pentium 4 Extreme
Edition (LGA775)
Pentium D Pentium
Extreme Edition Celeron
D (LGA 775)Core 2 Duo
Core 2 QuadCore 2
Extreme Pentium Dual
Core Pentium E6000
series
Page 13
Copyright, 2016
William A. Lloyd
LGA1155(Socket H2)
1,155
Jan-11
Core i3 2000 and 3000
series Core i5 2000 and
3000 series Core i7
2000 and 3000 series
Pentium G600, G800,
and G2000 series
Celeron G400 and G500
series
LGA1156(Socket H1)
1,156
Sep-09
Core i3 500 series Core
i5 600 and 700 series
Core i7 800 series
Pentium G6900 series
Celeron G1101
LGA1366(Socket B)
1,366
Sep-09
Core i7 900 series
Celeron P1053
LGA2011(Socket R)
2,011
Nov-11
Core i7 3800 and 3900
series
Slot A
242
Jun-99
Athlon (Cartridge)
Socket 462(Socket A)
453
Jun-00
Athlon (Socket 462)
Athlon XP Athlon MP
Duron Sempron (Socket
462)
Socket 754
754
Sep-03
Athlon 64 (Socket 754)
Sempron (Socket 754)
Socket 939
939
Jun-04
Athlon 64 (Socket 939)
Athlon 64 FX (Socket
939) Athlon 64 X2
(Socket 939) Sempron
(Socket 939)
Socket 940
940
Sep-03
Athlon 64 FX (Socket
940)
May-06
Athlon 64 (Socket AM2)
Athlon 64 FX-62 Athlon
64 X2 (Socket AM2)
Sempron (Socket AM2)
Socket AM2
940
Socket AM2+
940
Nov-07
Athlon 64 (Socket
AM2/AM2+) Athlon 64
FX-62 Athlon 64 X2
(Socket AM2/AM2+)
Phenom Sempron
(Socket AM2)
Socket AM3
941
Apr-10
Athlon II Phenom II
Sempron (Socket AM3)
Socket AM3+
942
Oct-11
Athlon II Phenom II
Sempron (Socket
AM3)FX
1,207
Nov-06
Athlon 64 FX-70, FX-72,
and FX-74
Socket FM1
905
Jul-11
A4, A6, A8, and E2
Socket FM2
904
2012
A4, A6, A8, A10, and E2
Socket F
For a more comprehensive list of CPU socket types from the 80486-class CPUs to date, refer to
Appendix A at the end of this course book. This list is subject to change over time.
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Page 14
Copyright, 2016
William A. Lloyd
CPU speeds, clock multipliers and voltages
When installing a CPU onto a motherboard, care must be exercised to make sure that the motherboard
has been configured properly for the type of CPU being installed on it. Failure to properly configure the
motherboard can result in a damaged CPU chip. When configuring the motherboard, three things must
be set for the CPU to operate properly:
1)
2)
3)
The CPU speed must be set. The speed of the CPU will range between 60 MHZ and 833MHz.
This will also be the speed of the "front end bus"; this is the bus between the CPU and the system
RAM. When using synchronous dynamic Random Access Memory (SDRAM), the RAM and CPU
will run synchronously, and as such both must be set for the same megahertz speed.
The clock multiplier must be set. CPUs accept data from the bus at one speed, and process the
data several times faster than it accepts the data. For example, an AMD K6-500MHz processor
runs at 100MHz for the data input speed, with a clock multiplier of 5. That is how the 500MHz
speed rating is set for the chip.
The CPU voltage level must be set. CPUs can run on voltages varying from 5V DC down to 2.2V
DC. You must consult the documentation for your CPU chip to determine the proper voltage level,
and then set the motherboard accordingly.
Configuring the motherboard can be done in a number of ways. Older motherboards have jumpers
and/or switches built onto them that allow the board to be configured properly. Newer motherboards can
be configured from within the Complementary Metal-Oxide Semiconductor (CMOS) setup program. On
these newer motherboards, the voltage is automatically configured; the motherboard queries the CPU,
and then automatically sets the proper voltage level. The user then sets the CPU speed and clock
multiplier from within the CMOS setup program.
It is important in this configuration process that the user consults both the motherboard documentation
and the documentation for the CPU chip. Over-clocking a chip can cause increased heating of the chip,
which can cause the chip to fail. Providing the chip with too much voltage for even a short period of time
will also cause the CPU to fail.
Heat sinks and CPU cooling fans
It is very important that the user installs a combined heat sink and CPU cooling fan properly upon the chip
before operating the chip. CPU chips become hot very quickly, and CPU failure will begin to occur if the
chip temperature exceeds 150 degrees Fahrenheit. The CPU chip will reach this temperature within one
to two minutes without the benefit of a cooling fan and heat sink. Therefore, a heat sink with a cooling fan
is vital to the proper operation of the CPU chip.
Further, it is wise to apply heat sink compound to the top of the CPU before installing the heat sink. This
white silicone grease ensures that all of the heat generated by the CPU will be transferred to the heat
sink. Heat sink compound is available at most any electronics store, and costs only a few dollars, but it
will ensure a long life for your CPU chip.
Finally, the cooling fan portion of the heat sink should be checked periodically for dust buildup. As dust
accumulates in your PC over time, the CPU cooling fan can become clogged with dust. This dust buildup
can slow and eventually stop your cooling fan from operating. This will cause increased heating on the
CPU, which may lead to failure of the chip. Keeping the cooling fan free of dust buildup will ensure proper
operation of the fan and reduced operating temperatures for the CPU. If the fan has been rendered
inoperative because of dust buildup, and if removing the dust buildup does not correct the problem,
replace the cooling fan/heat sink as soon as possible.
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Copyright, 2016
William A. Lloyd
Computer cases
Computer cases come in several different types and sizes. Older AT-style cases will accept traditional
AT-sized motherboards, and AT-style cases are usually manufactured in both desktop and tower form
factors. ATX-style cases will accept the newer style ATX-style motherboards. ATX form-factor
motherboards are more rectangular than AT-style motherboards, and are designed to minimize the
number of cables cluttering the inside of the case.
The power-on button at the front of the case connects directly to the motherboard, as do the power-on LED,
HDD activity LED, motherboard speaker connection, and the reset switch.
ATX motherboards have the serial, parallel, PS/2 and USB ports built directly onto the rear of the
motherboard, as shown in the illustration below.
The green and the purple connectors are the PS/2 connectors used by the keyboard and mouse
respectively. Immediately right of the PS/2 connectors are two USB 2.0 connectors, The red female
connector (with 25 holes) is a parallel port and below that are the two serial male ports with nine pins.
There is also a type of motherboard form factor called NLX; it uses a riser card to allow for the addition of
expansion cards to the system. These types of motherboards are usually seen in more proprietary
systems, and they require an NLX-style case to hold them.
Recently, the Mini ITX has become one of the most common small form factor mainboard standard.
High-end mini ITX mainboards support standard desktop CPUs, use standard memory DIMM sockets
and feature a full size PCI-E x16 slot with support for the fastest graphics cards. This allows customers
to build a fully fledged high-end computer in a significantly smaller case.
Computer cases come in desktop and tower configurations. Tower cases can be mini-sized, mid-sized, or
full sized; the larger cases allow the user to add additional drives or devices. Desktop cases vary much
less in size. NLX-style cases are designed for desktops, and are smaller in height than traditional desktop
cases. Mini-ITX cases are even smaller. Larger cases usually have more powerful power supplies, in order
to accommodate additional devices installed into the system.
An example of a Mini ITX-style motherboard is shown below:
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William A. Lloyd
Power supplies
The power supply in the computer case provides electrical power to motherboard, disk drives, and
occasionally to the monitor also by a connector in the back of the power supply. The power supply also
has a fan on it to cool the computer (and power supply) by drawing air through the front panel into the
power supply and blowing it out the back of the unit. Power supplies are rated in terms of wattage; most
typical power supplies provide 400 - 900 watts of available power for devices within the PC's case. This
amount will supply a system board, 8 cards inserted into its sockets, and 4 drives (floppy, hard, ZIP, tape
or optical drives). The more wattage a power supply can handle, the more devices can be installed into
the system.
Many power supplies are circuit-breaker protected; that is, if there is a short somewhere on the system
board or if a power cable has accidentally been attached wrong (which usually means forcing the plug
into a device the wrong way), a circuit breaker will disconnect power and not create any damage to the
system or its components. However, many power supplies are cheaply made, and do not offer
circuit-breaker protection to the user. Check with the manufacturer or vendor before buying a case and
power supply to see if the supply has built-in circuit-breaker protection. Virtually all power supplies will
operate on either 110-120 volts AC, or 220-240 volts AC in other countries.
Older AT-power supply connectors to the motherboard can be plugged in backwards, while ATX-power
supply connectors to the motherboard can only be installed one way. Power supply connectors that
attach to drives will only fit on the device one way; they cannot be forced on without damaging the unit.
Current technology power supplies have either a 20 or 24-pin connector, with an additional 4-pin
connector that connect to the system board. Some power supplies also have a 6-pin connector that plugs
into higher-end video cards. Several Molex-type and/or SATA power supply connections provide
electricity to hard drives and optical drives.
An example of an ATX-style power supply is shown below:
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Copyright, 2016
William A. Lloyd
Types of memory
Memory is installed onto typical motherboards by snapping Single In-line Memory Modules (SIMMs) or
Dual In-line Memory Modules (DIMMs) into sockets on the motherboard. Several main types of memory
modules are shown on the next page.
72-pin SIMMs [obsolete]
Older Pentium-based systems use 72-pin SIMMs, installed in banks of two at a time. There is also a
left-hand notch and offset dimple near the center of the SIMM to ensure proper installation. Many 72-pin
SIMMs are non-parity memory; that is, they do NOT have a specific chip built in for memory testing and
error detection. There are several types of 72-pin SIMMs, including fast-page memory, extended data
output (EDO) memory, and synchronous dynamic RAM (SDRAM).
Determining the type of memory is not easily done by sight alone; a good memory testing machine or
memory vendor can identify the type of SIMM memory. This type of memory is now obsolete.
DIMM memory types
Newer computer systems use DIMMs, which can be installed one at a time. The two or three-part
connector at the bottom of the DIMM ensures proper installation of the unit into its socket. DIMMs can
only be inserted one way onto the system board. Most DIMMs are DDR (Double data rate) or SDRAM in
type. Identification of a DIMM's type by sight alone is not straight-forward. Usually a memory tester or
knowledgeable memory vendor is needed to properly identify the type of memory contained in a DIMM.
Memory is timed as to how fast it will reliably operate. This timing information is recorded on the chips
found on the SIMM or DIMM. Usually the timing marks will look like what is shown in the image above:
1GB, DDR, 400, CL3
The label shown in the image above indicates that the memory capacity is 1 gigabyte, double data rate
style, operating at 400 megahertz, with a clock multiplier of three.
When installing memory units into a motherboard, you must install devices of the same speed; installing
mismatched memory units will very likely cause problems. A simple inspection of the memory units will
prevent you from making such a mistake when installing new memory. If you find that another technician
has made a mistake and installed mismatched memory, simply replace some of the memory units in the
system until all of them are running at the same speed.
Within these types of modules, the several different varieties of memory are discussed below.
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William A. Lloyd
Parity memory
This type of memory uses a method of error checking in which an extra bit is used to indicate whether an
even or odd number of binary 1 bits were stored in memory. When parity is used, a parity bit is added to
each transmitted character. The bit’s value is 0 or 1, to make the total number of 1s in the character even
or odd, depending on which type of parity is used. Most older parity SIMMs have an extra memory chip
installed on them to handle parity checking issues. This type of memory is also called fast-page memory.
Parity memory typically is used on high-end file servers.
Non-parity memory
This type of memory does not use a parity checking mechanism to test the validity of the data stored in it.
The operating system and BIOS use other methods to test and determine if the memory is operating
properly and accurately storing information. As with parity memory, this type of memory is also called
fast-page memory.
Extended Data Out (EDO) memory
This type of memory operates more quickly than fast-page memory. The RAM chips on the SIMM or
DIMM allow for timing overlaps between successive reads/writes, which improves memory cycle and
access time.
Synchronous Dynamic Random Access Memory (SDRAM)
This type of RAM runs at the same speed as the main system bus, which can significantly enhance
system performance. For example, EDO memory may run at 60 nanoseconds (ns), while SDRAM can
run at 10 or 8 nanoseconds, depending upon the motherboard. Double-Data-Rate (DDR) DIMMS transfer
twice as much information at one time as compared to typical SDRAM DIMMs.
Static Random Access Memory (SRAM)
Short for static random access memory, and pronounced ess-ram. SRAM is a type of memory that is
faster and more reliable than the more common DRAM (dynamic RAM). The term static is derived from
the fact that it doesn't need to be refreshed like dynamic RAM.
RAMBUS
This type of memory is also known as RDRAM, for RAMBUS Dynamic Random Access Memory. This
high-speed memory transfers data at 1GB per second or faster. This is a significant speed upgrade to
even SDRAM. Memory modules with RDRAM chips on them are also called RIMMs, which stands for
RAMBUS Inline Memory Modules. RAMBUS memory is obsolete, as many manufacturers did not
choose to adopt this style of memory as a standard.
ECC memory
ECC is short for Error-Correcting Code memory, a type of memory that includes special circuitry for
testing the accuracy of data as it passes in and out of memory. ECC memory typically is used on
higher-end computers and servers, and this memory type uses parity checking as well.
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William A. Lloyd
SODIMM
Small Outline Dual In-line Memory Modules (SODIMMs) are smaller-sized DIMM memory modules are
designed to be installed into laptop or portable computers. They are comparable to DIMMs for desktop
computers, but simply smaller in size.
An example of SODIMM memory is shown in the image below:
Single-sided vs. double-sided memory
Single-sided or Double-sided is a physical term describing the arrangement of chips on one side or two
sides of the memory module. Double-sided memory refers to how the module is physically built with the
individual memory chips. In Double-sided memory, RAM chips are placed on both sides of the printed
circuit board (PCB).
Single-sided memory modules are newer, have RAM chips on only one side of the PCB, and the chips
are denser, enabling more capacity. Older motherboards may not recognize single sided memory.
Single-channel vs. dual-channel vs. triple-channel RAM
Single-channel-enabled memory controllers in a PC system architecture utilize one 64-bit data channel
to transmit data.
Dual-channel-enabled memory controllers in a PC system architecture utilize two 64-bit data channels.
Dual channel should not be confused with double data rate (DDR), in which data exchange happens
twice per DRAM clock. The two technologies are independent of each other and many motherboards
use both, by using DDR memory in a dual-channel configuration.
Triple-channel-enabled memory architecture (DDR3) is used in the Intel Core i7-900 series and higher
processors. The LGA 1366 platform (e.g. Intel X58) supports DDR3 triple-channel, normally 1333 and
1600Mhz, but can run at higher clock speeds on certain motherboards.
AMD Socket AM3 processors do not use the DDR3 triple-channel architecture but instead use dualchannel DDR3 memory. The same applies to the Intel Core i3, Core i5 and Core i7-800 series, which are
used on the LGA 1156 platforms (e.g., Intel P55). According to Intel, a Core i7 with DDR3 operating at
1066 MHz will offer peak data transfer rates of 25.6 GB/s when operating in triple-channel interleaved
mode. This, Intel claims, leads to faster system performance as well as higher performance per watt.
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William A. Lloyd
When operating in triple-channel mode, memory latency is reduced due to interleaving, meaning that
each module is accessed sequentially for smaller bits of data rather than completely filling up one
module before accessing the next one. Data is spread amongst the modules in an alternating pattern,
potentially tripling available memory bandwidth for the same amount of data, as opposed to storing it all
on one module.
The architecture can only be used when all three, or a multiple of three, memory modules are identical in
capacity and speed, and are placed in three-channel slots. When two memory modules are installed, the
architecture will operate in dual-channel architecture mode.
Installing memory
When installing memory on a motherboard, one must fill a "bank" of memory at a time for the memory to
be recognized by the system. For example, with older 72-pin SIMMs, the user must install 2 SIMMs at a
time onto the system board.
DIMMs can be installed either one or two at a time, depending upon the system board design. Also, most
motherboards have several banks that can be filled; you must fill the first bank (usually numbered Bank 0
or Bank 1) before filling the other banks with memory.
You will need to check the documentation for your motherboard to determine which is the first bank of
sockets on the board, and also determine the exact type of memory that the system board supports.
Online vendors such as www.crucial.com have information on their websites that will tell you the
maximum amount of memory the system board will support, and the type of memory that can be installed.
Memory devices like SIMMs, DIMMs and SODIMMs have been designed so that they will install only
ONE way into their sockets on the system board. They cannot be installed backwards or the wrong way.
When installed properly onto a system board, you will hear a click when the DIMM locks into the socket.
Be sure that the socket on the system board is free from dust or particulate matter before inserting the
DIMM into the socket. Any dust or foreign matter may prevent the DIMM from being recognized or
operating properly.
NOTES
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William A. Lloyd
Floppy drives, ZIP drives and LS-120 drives [obsolete]
A 3.5-inch floppy drive is used to make data portable, so that it can be transferred from one PC to
another. However, the capacity of current floppy disks is only 1.44MB, which is very small by today's
standards. Still, floppy disks can be used to boot a PC, and they can be used as a medium for backing up
data as well as storing application data files.
3.5-inch floppy disks are obsolete, as their storage capacity has been far exceeded by writable
CD, DVD and flash-drive technology. However, in some places in the world, floppy disks still are
being used for data storage.
EXTREMELY old PCs may have a 5.25-inch floppy drive built into them. These drives are beyond
obsolete, and the disks required to use them have not been available for purchase in stores for years.
Other re-writable disk media exist to make your data portable. Obsolete ZIP disks, created by the Iomega
Corporation, allow you to store either 100MB or 250MB of data onto a disk slightly larger than a traditional
floppy disk.
Obsolete LS-120 drives, created by Imation Corporation, allowed the user to store 120MB of data onto a
special disk that is the same size as a 3.5-inch floppy disk; they also allowed the use of traditional
3.5-inch 1.44MB disks in the drive as well.
Both of these drives are available in external and internal versions; internal drives are mounted inside the
PC's case, and external drives are connected to the PC via the parallel port or a special adapter card.
ZIP drives and LS-120 drives are IDE-class devices, and plug into the same cable as your hard drive
and/or CD-ROM drive.
ZIP disks and LS-120 drives are obsolete, as their storage capacity has been far exceeded by
writable CD, DVD and flash-drive technology. However, you may encounter some of these drive types
in older computers brought in for repair.
Below is an illustration of a typical floppy drive, and an Iomega ZIP drive.
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William A. Lloyd
Hard drives (IDE, EIDE, UltraATA, SCSI, SATA and SSD types)
A hard drive stores large quantities of data for use at a later time. Your operating system, application
software and personal data all will reside on your hard drive.
The drive will connect to either an IDE interface on the system board of your computer, a SATA interface,
or in the case of Small Computer Systems Interface (SCSI) drives, you will need a special controller
called a SCSI host adapter.
Below is an illustration of a typical hard drive.
How hard drives store data
A hard drive contains several round metal platters inside the case, with a magnetic substance covering
the disks. A read/write head and actuator arm moves the heads back and forth over the disks as they
rotate between 5400, 7200 and 10,000 revolutions per minute (RPM). The faster the drive spins, the more
rapid the data access time. A disk controller board underneath the drive allows data to be transferred to
and from the computer.
The disk is hermetically sealed, which means that a small quantity of totally dust-free air (within a
clean-room environment) is contained inside the drive. NEVER open the drive to expose the disk platters
inside; this will permanently void the warranty and damage the drive mechanism.
The read/write heads pass over the surface of the disk platters at a distance of approximately 4
angstroms, which is less than the width of a human hair. If the heads were to impact the disk, the
magnetic coating on the disks would be damaged and data corruption is quite likely. If the disk is exposed
to normal air, dust particles (which typically are about 100 angstroms in size) will impact against the disk
heads and damage the device.
Data is stored on the hard drive in cylinders and sectors. On any disk platter, data is written onto a
concentric circle (called a track) on both the top and bottom side of the disk. When you consider the same
track on the top and bottom of all of the disk platters, that is called a cylinder. Each cylinder (or track) is
divided into pie-slice segments called sectors. On the product label of the hard drive, it will list the number
of cylinders, read/write heads, and the number of sectors per track. These are referred to as the CHS
values for the drive.
Some pictures that illustrate how the hard drive is magnetically divided into cylinders and sectors are
provided on the next page.
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William A. Lloyd
Images of how hard disks store data
What a SATA hard drive looks like inside the case
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William A. Lloyd
The following is a review of the major hard drive types:
Integrated Drive Electronics (IDE) drives have the hard disk controller built
into the drive unit itself, and data is passed to a drive interface on the
system board. IDE-style drives use 40-pin ribbon cable to transmit data.
IDE/EIDE drives:
Enhanced IDE (EIDE or Enhanced ATA) drives have disk capacities
greater than 528 megabytes. These drives still are widely used in PCs
today, though they are quickly becoming obsolete.
IDE and EIDE drives also are called Parallel ATA (PATA) drives.
Similar to Enhanced IDE drives, but they use an 80-conductor cable and
an additional Direct Memory Access (DMA) channel to transfer more data
faster than typical EIDE drives.
UltraATA/UltraDMA
drives:
Newer drives use UltraATA/UltraDMA technology, and controller interfaces
on motherboards that accommodate this technology are now widely
available.
Different implementations of UltraATA/UltraDMA allow for 33, 66, 100 or
133MB of data transfer per second.
An 80-conductor UltraATA cable looks quite similar to a standard
40-conductor IDE data cable, so be sure to examine the cable closely
before connecting it to the drive.
Note that IDE/EIDE and UltraATA/DMA drives must be jumpered to a
Master, Slave or Cable Select position on each drive, so that the drive
controllers will operate properly (just like other IDE/EIDE drives).
Up to two IDE/EIDE drives can be connected to one data cable. If two
drives are connected to one cable, one of the drive controllers has to be
disabled, so that there are no data transfer conflicts.
One drive controller will be set as the Master, and it will operate both
IDE/EIDE drives. The other drive controller must be set to Slave mode,
which effectively disables the controller interface.
This point is discussed in more detail later in this text.
These UltraATA and UltraDMA drives still are widely used in PCs today,
though they are quickly becoming obsolete with the advent of SATA hard
drives.
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William A. Lloyd
SCSI drives:
Small Computer Systems Interface (SCSI) drives use a SCSI host adapter
(controller) interface, and they can transfer data at a much faster rate than
EIDE or UltraATA. SCSI drives are also more expensive. SCSI drives use
50-pin or 68-pin cables to transmit data.
There are several implementations of SCSI: SCSI 1, SCSI 2, Fast SCSI,
SCSI Wide, UltraSCSI, and Low-Voltage Differential. Each implementation
provides faster transfer of data and increased data bandwidth.
Drives are identified by setting a series of SCSI ID jumpers on each device;
SCSI ID numbers range from 0 through 6.
Further, the last (highest numbered) device in the chain (or cable) must be
"terminated"; that is, a terminating resistor must be installed (or a
terminator jumper set to enabled) to indicate to the host adapter which unit
is the last drive on the chain.
SCSI drives can be hot-swappable, which allows a drive to be removed
and re-installed in a system without powering down the computer.
Below is a description of the various kinds of SCSI types.
Single ended SCSI: Transmits "normal" electrical signals. Uses open
collector to the SCSI bus. The maximum length for SCSI-1 is a 6 meter
cable. Most devices are single ended.
Differential SCSI: Uses two wires to drive one signal. The maximum cable
length is 25 meters. Electrically incompatible with single ended devices.
Used with SCSI-1 and upwards.
Apple SCSI: The single ended 50 pins cable has been reduced to 25 pins
by tying most of the ground wires together. DB25 connector (like a parallel
port). Often used as the external SCSI connector.
Asynchronous SCSI: A way of sending data over the SCSI-bus. The
initiator sends a command or data over the bus and then waits until it
receives a reply (e.g. an ACK, or acknowledge). All commands are send
asynchronously over the 8 bit part of the SCSI-bus.
Synchronous SCSI: Rather than waiting for an ACK, devices that both
support synchronous SCSI can send multiple bytes over the bus. This
improves throughput, especially if you use long cables.
Fast SCSI: Fast SCSI allows faster timing on the bus (10MHz instead of
5MHz). On a 8 bit SCSI-bus this increases the *theoretical* maximum
speed from 5MB/s to 10MB/s.
Ultra SCSI: Allows up to 20MHz signals on the bus.
Wide SCSI: Uses an extra cable (or 68 pin P cable) to send the data 16 or
32 bits wide. This allows for double or quadruple speed over the SCSI-bus.
Note that no *single* drive reaches these speeds, but groups of several
drives can.
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RAID: A Redundant Array of Independent Disks is a set of drives
connected to a special dual ported SCSI adapter that allows certain types
of access optimization. A RAID 0 array stripes the data across multiple
drives to decrease data latency. A RAID 1 array mirrors the data on
multiple drives for increased data integrity. A RAID 5 array uses extra
drives in a distributed manner to store parity information that can be used to
apply data correction and recover any data in the event of any individual
disk failure. This provides high reliability. A RAID 10 array requires a
minimum of four disks, and stripes data across mirrored pairs. As long as
one disk in each mirrored pair is functional, data can be retrieved. If two
disks in the same mirrored pair fail, all data will be lost because there is no
parity in the striped sets
So what type of SCSI port does the host adapter have? Is it 8-bit (narrow)
or 16-bit (wide) and is it single-ended SCSI or differential (High Voltage
Differential, or HVD) SCSI? Here are two things you can do to determine
this information:
1.
To determine if it is an 8-bit or 16-bit system, simply look to see if the SCSI
connector has 50 pins or 68 pins. The 50-pin connector is an 8-bit system
and the 68-pin connector is a 16-bit system. For convenience, check the
"SCSI BUS CONNECTORS" drawing below. Note that older Macintosh
computers use a 25-pin connector and are always single-ended.
2.
To determine if the SCSI host is single-ended or differential (HVD) requires
the use of an ohmmeter. Make sure the power to the computer is turned off.
Pull the cable connector off the host's SCSI port and measure the
resistance between pins 2 and 24 on high-density or Centronics-type
50-pin connector or between pins 2 and 33 on a 68-pin connector. If you
ever run into a DB-50 type SCSI connector, measure between pins 3 and
49. If the resistance is a few tenths of an ohm or less, it is a single-ended
SCSI port. If it is more than a few tenths of an ohm (probably something
over 1 ohm), it is a differential (HVD) SCSI port. This technique can also be
used to determine if the port on a SCSI peripheral is single-ended or
differential (HVD).
Often abbreviated as SATA or S-ATA, these drives evolved from the
Parallel ATA (IDE/EIDE) physical storage interface. Serial ATA is a serial
link - a single cable with a minimum of four wires creates a point-to-point
connection between devices. SATA data transfer begin at 150MBps.
One of the main design advantages of Serial ATA is that the thinner serial
cables facilitate more efficient airflow inside a form factor and also allow for
smaller chassis designs. In contrast, IDE cables used in parallel ATA
systems are bulkier than Serial ATA cables and can only extend to 40cm
long, while Serial ATA cables can extend up to one meter.
SATA drives have greater storage capacities than do PATA drives; most
SATA drives begin at 120GB capacities, and many exceed 3 Terabytes
(TB) of capacity. External SATA (e-SATA) drives are hot-swappable.
Serial ATA (SATA)
hard drives:
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SATA drives also have the advantage of not requiring to be jumpered to the
Master, Slave or Cable Select configurations used in Parallel ATA (PATA)
drives. A SATA drive connects directly to the SATA interface on the system
board or controller card. There is one data cable connection from each
drive to a single SATA interface connection; drives are not daisy chained
together, as with PATA hard drives.
By comparison, PATA drives are daisy-chained along a ribbon cable with
one plug to the system board or interface card and 2 connectors along the
length of the cable. Because each PATA drive has a controller board on it,
each drive must be set to indicate whether it is the Master drive (the one
that controls both units along the cable length), or the Slave drive (the one
that is controlled by another drive on the cable), or to the Cable Select
position (the drive at the end of the cable controls any other drives along
the ribbon cable).
Many customers over the years have had difficulty understanding this
concept when installing additional hard drives (or CD-ROM drives) in a
computer, and the various drive manufacturers never settled on a
consistent pattern for setting drive jumpers. Often one must look upon the
label on the drive (if such a label exists) for the jumper-setting scheme, or
contact the manufacturer (via the Web) for the proper instructions. SATA
drives remove that obstacle for the customer.
Solid-state drives:
Abbreviated SSD, a solid state disk is a high-performance plug-and-play
data storage device that contains no moving parts. SSD components
include either DRAM or EEPROM memory boards, a memory bus board,
a CPU, and a battery card.
Because they contain their own CPUs to manage data storage, they are a
lot faster (18MBps for SCSI-II and 35 MBps for UltraWide SCSI interfaces)
than conventional rotating hard disks; therefore, they produce highest
possible I/O rates. Storage capacities for SSDs now can reach 1TB.
SSDs are most effective for server applications and server systems, where
I/O response time is crucial. Data stored on SSDs should include anything
that creates a bottleneck, such as large databases, swap files, library and
index files, and authorization and login information. SSDs now are
becoming available for laptop and desktop computers as well.
While solid state disk (SSD) is the most common acronym, SSD is also
used for solid state drive or solid state disk drive, replacing disk with drive in
the acronym.
USB flash drives:
While not truly a “hard drive”, USB flash drives allow the user to store large
quantities of data that in the past would have required an external hard
drive. USB flash drives are somewhat similar to solid-state drives in that
they have no moving parts. However, flash drives are designed to be
inserted and removed as needed from the user’s computer or device, and
they allow data to be made portable from one system to another.
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Flash drives of 32GB, 64GB, 128GB or 256GB capacities are not
uncommon these days. Flash drives can be made bootable, can be used
as an operating system install media, and can even accommodate an
entire working operating system like Ubuntu or Knoppix.
These types of drives include compact flash cards and SD cards
(including Micro-SD, Mini-SD, xD, and eMMC formats), which are
installed in various kinds of devices, such as digital cameras,
smartphones, and tablets. These compact flash cards typically install in
devices through a dedicated port on the device, which is specific to a
particular kind of card.
PCs and laptops may have such card reader ports, or the user can get a
USB plug-in device that adapts the card for connection to the computer.
Internal card readers are now also commonly made to fit in the case slot
reserved for a 3.5-inch floppy drive, and can accommodate a variety of
compact flash or SD-style cards.
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Optical (CD-ROM, DVD-ROM, Blu-ray) drives and tape drives
CD-ROM drives read data from Compact Discs (CDs); up to 700MB of data can be stored on 1 CD.
Original CD-ROM drives use READ-ONLY technology; therefore, you cannot write to a Compact Disc in
a plain CD-ROM drive. However, CD-R drives can read and write data onto blank CD disks, and CD-RW
drives can read, write and rewrite data onto blank CD disks.
DVD-RW drives now have become the standard, since they can read and write a significantly-larger
amount of data than original CD-ROM disks. A DVD disk will hold up to 4.7 GB of data, and a dual-layer
DVD disk (DVD-DL) will hold up to 9.4GB of data.
Newer Blu-Ray drives and the disks they use will hold significantly more data in the same physical
amount of space than DVD disks (25GB for a single-layer disc, and 50GB for a dual-layer disc). Blu-ray
drives are often used for playback of movies and other video-based content.
DVD-RW drives and the disk media used in them have come down significantly in price over the past few
years. At the time this text was written, a dual-layer DVD-RW drive can be purchased for under $30.00.
CD and DVD drives use the IDE, SCSI or SATA drive interfaces.
Below is an illustration of a typical optical drive; CD-ROM, DVD-ROM and Blu-ray drives will all look the
same, except there will be a symbol on the disk drawer indicating the drive’s type and capabilities.
Tape drives are designed primarily to backup critical data on a hard disk in the event of a hard disk failure.
Tape drives can be used to backup an entire hard disk, or only portions of the disk, and this process is
controlled by backup software such as Microsoft Backup. Over the years, the ability of a tape backup
device to store large sums of data has grown significantly.
Tape drives can backup gigabytes of data, whereas a few years ago these drives could hold only a few
hundred megabytes of data. Tape drives are not normally used for typical data storage such as hard
drives and optical disks, mainly because of the length of time it takes to retrieve a file from tape. Tape
drives are generally SCSI devices, but can be IDE style devices as well.
Tape drives are used primarily in industrial or business settings, and are not used by the average
consumer. With the advent of inexpensive, larger-capacity hard drives, as well as cloud-based data
storage, tape drives are coming closer to obsolescence every day.
An illustration of a tape drive is shown below:
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Video hardware (SVGA/VGA, PCI, AGP, PCIe/PCIx)
A video card is an adapter card that sends video signals to the monitor; there are three main kinds of
video cards in use today:
Current video card types
VGA/SVGA:
Video Graphic Adapters (VGA) and Super Video Graphics Adapters (SVGA) output a
higher number of colors and much higher-resolution graphics. Video resolutions can be
adjusted, from 640 x 480 pixel format up to 1680 x 1200 format, with color palettes ranging
from 16 colors up to 32,767,000 colors.
The amount of colors and resolution format are dependent upon the video production chip
and amount of video RAM on the video card. VGA/SVGA cards come in ISA and PCI bus
connector configurations.
AGP:
Accelerated Graphics Port (AGP) cards provide the same video formats as with
VGA/SVGA, but adapted to work on a special AGP socket found on newer motherboards.
The Accelerated Graphics Port (AGP) is a special type of high-speed video bus slot that is
used exclusively for high-end video cards. It has the ability to transfer 32 bits of data at
66MHz speed, with up to a clock multiplier of up to four times. At that rate of speed, an
AGP connection can transfer 1,066MB of data per second.
AGP ports also give a direct connection to the system RAM, thus reducing the need for
large sums of video memory. AGP ports are appropriate for high speed rendering of
images, 3-D video, and other types of high speed video production.
The AGP interface has now been superseded by the PCI-Express interface, which is
discussed below.
PCI-E/PCI-X: The PCI Express (or PCI-E) is a two-way, serial connection that carries data in packets
along two pairs of point-to-point data lanes, compared to the single parallel data bus of
traditional PCI that routes data at a set rate. Initial bit rates for PCI Express reach 2.5Gb/s
per lane direction, which equate to data transfer rates of approximately 200MB/s.
PCI Express was developed so that high-speed interconnects such as 1394b, USB 2.0,
InfiniBand and Gigabit Ethernet would have an I/O architecture suitable for their transfer
high speeds.
PCI Express, also known as 3GIO (for third-generation Input/Output) is compatible with
existing PCI systems
By comparison, PCI-X uses a parallel interconnect along a bus that is shared with other
PCI-X devices, just like PCI. In fact, PCI-X is best thought of as "PCI-eX tended", as it is
simply an extension of the legacy PCI 32-bit format, with which it is backward-compatible.
It differs mainly in the fact that the bus is now 64-bits wide, and runs at higher frequencies
(now up to 533MHz, compared to 66MHz - the fastest PCI frequency).
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Video resolution, pixels, dot pitch and refresh rates
Video resolution for all of these video card types is measured in terms of picture elements, or pixels.
Pixels are a combination of red, green and blue dots displayed and overlaid one of another. By
changing the color saturation between these three colors, one can create images of virtually any color.
The more pixels displayed on the screen at a time, the higher the video resolution (also called the aspect
ratio). While higher resolution does allow for larger images on the screen at one time, normal screen fonts
and desktop icons become smaller as the aspect ratio increases. Most monitors will display between
800- by-600 resolution and 1920-by-1024 resolution, with 1024-by-768 resolution as a typical value.
Older monitors are more square in dimension, and will have what is called a 4-by-3 (4:3) aspect ratio.
Newer monitors are rectangular in size, and will have a 16:9 or a 16:10 aspect ratio, which will
accommodate high-definition video normally seen on HD televisions.
Monitors are measured as to the number of pixels they can display in terms of their dot pitch; this is the
measurement of the distance between any 2 pixels displayed on the screen. The smaller the dot pitch (or
distance between pixels), the more pixels can be displayed on the screen at one time. The dot pitch is a
function of the metal mesh within the monitor; it cannot be changed or adjusted by the user.
Also, video cards transmit signals to monitors in such a way that the image on the screen is “refreshed” or redrawn a number of times per second. This is referred to as the “refresh rate. Older monitors will have a
refresh rate of 60Hz or 72Hz; that is, the video image is redrawn 60 or 72 times per second. Newer
monitors will refresh near 90Hz, and HD-TV screens (which can be used with newer PCs) can have
refresh rates up to 240Hz.
Current video cards likely will have either a standard 15-socket VGA output, and/or a DVI output, and/or
an S-video output, and/or an HDMi output connector. These connector types are discussed further on the
next page. Adapter plugs are readily available that can convert VGA signals to DVI (or vice versa), DVI
to HDMi, or even HDMi to VGA, to accommodate various monitors.
Newer video cards can accommodate having two monitors connected at the same. This allows the user
to “extend the desktop” within Windows, and permits several applications to be displayed on the
screens at the same time.
It is important that your video card and your monitor work together properly, so that you can see the
images on the screen. If your video card outputs signal at a refresh rate that the monitor cannot support,
the image on the screen will spin uncontrollably, or your monitor will simply go blank. These factors can
be controlled in the Display Properties icon in the Windows Control Panel.
Below is an illustration of a typical video card with built-in VGA (blue), DVI (white) and S-Video (round)
connectors.
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Video connector types
HDMI and DisplayPort
Short for High-Definition Multimedia Interface, HDMi is the first industry-supported uncompressed, alldigital audio/video interface. It's a single cable and user-friendly connector that replaces the maze of
cabling behind the home entertainment center. HDMI provides an interface between any audio/video
source, such as a set-top box, DVD player, or A/V receiver and an audio and/or video monitor, such as
a digital television (DTV), over a single cable. There are two kinds of HDMi connection plugs: the
standard HDMI connector, and the newer miniHDMi, which is smaller in size.
HDMI supports standard, enhanced, or high-definition video, plus multi-channel digital audio on a single
cable. It transmits all ATSC HDTV standards and supports 8-channel digital audio with bandwidth to
spare to accommodate future enhancements and requirements, according to HDMI.org.
HDMI was defined to carry 8 channels, of 192kHz, 24-bit uncompressed audio, which exceeds all current
consumer media formats. In addition, HDMI can carry any flavor of compressed audio format such as
Dolby or DTS. HDMI has the capacity to support existing high-definition video formats such as 720p,
1080i, and 1080p, along with support of enhanced definition formats like 480p, as well as standard
definition formats such as NTSC or PAL.
Display Port is very similar to HDMi, but the connector (and cables) are slightly different in appearance
than HDMi. The creators of DisplayPort hoped the connection type would gain wide acceptance, but it
never caught on as did HDMi. You can easily find cables that will convert DisplayPort output to HDMi.
The image below shows an HDMi-to-DisplayPort cable; the HDMi connector is on the left, and the
DisplayPort connector is on the right.
S-Video
Short for Super-Video, a technology for transmitting video signals over a cable by dividing the video
information into two separate signals: one for color (chrominance), and the other for brightness
(luminance). When sent to a television, this produces sharper images than composite video , where the
video information is transmitted as a single signal over one wire. This is because televisions are designed
to display separate Luminance (Y) and Chrominance 8 signals. (The terms Y/C video and S-Video are the
same.)
Computer monitors, on the other hand, are designed for RGB signals. Most digital video devices, such as
digital cameras and game machines, produce video in RGB format. The images look best, therefore,
when output on a computer monitor. When output on a television, however, they look better in S-Video
format than in composite format.
To use S-Video, the device sending the signals must support S-Video output and the device receiving the
signals must have an S-Video input jack. You also need an S-Video cable to connect the two devices.
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Component / RGB
Component RGB uses a set of RCA cables to transmit the video signal from a device (like a video card or
a unit such as an xBox or PlayStation console) to a television monitor or similar display. Once cable, the
yellow one, transmits the video signal, and the red and white cables transmit the left and right audio
channels from the component to the display device.
DVI
Short for Digital Visual Interface, a digital interface standard created by the Digital Display Working Group
(DDWG) to convert analog signals into digital signals to accommodate both analog and digital monitors.
Data is transmitted using the transition minimized differential signaling (TMDS) protocol, providing a
digital signal from the PC's graphics subsystem to the display. The standard specifies a single plug and
connector that encompass both the new digital and legacy VGA interfaces, as well as a digital-only plug
connector. DVI handles bandwidths in excess of 160 MHZ and thus supports UXGA and HDTV with a
single set of links. Higher resolutions can be supported with a dual set of links.
There are 3 different types of DVI connectors. DVI-A provides analog signals to a monitor, and DVI-D
provides digital signals to a monitor. DVI-I (the I stands for “integrated”) can carry both analog or digital
signals to a monitor.
A chart that shows the appearance of DVI-A, DVI-D and DVI-I cable plugs is shown below.
Set-top Boxes and Smart TVs
A set-top box (STB) or set-top unit (STU) is a device that generally contains a TV-tuner input and
displays output to a television set and an external source of signal, turning the source signal into
content in a form that can then be displayed on the television screen or other display device. They are
used in cable television, satellite television, and over-the-air television systems, as well as other uses.
For example: older televisions that can only receive analog over-the-air TV signals (which are now
obsolete) can be made to display digital TV channels through the use of a set-top converter box.
A smart TV, sometimes called a connected TV or hybrid TV, is a television set or set-top box with
integrated Internet and Web 2.0 features, and is an example of technological convergence between
computers and television sets and set-top boxes.
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Besides the traditional functions of television sets and set-top boxes provided through traditional
broadcasting media, these devices can also provide Internet TV, online interactive media, over-the-top
content, as well as on-demand streaming media, and home networking access.
Smart TV should not to be confused with Internet TV, IPTV or Web TV. Internet TV refers to the
receiving television content over internet instead of traditional systems, such as terrestrial, cable and
satellite signals. Internet Protocol television (IPTV) is one of the emerging Internet television technology
standards for use by television broadcasters. Web television is a term used for programs created by a
wide variety of companies and individuals for broadcast on Internet TV.
In smart TVs, the operating system is preloaded or is available through set-top box. The software
applications or apps can be preloaded into the device, or updated or installed on demand via an app
store or app marketplace, in a similar manner to how the apps are integrated in modern smartphones.
The technology that enables smart TVs is also incorporated in external devices such as set-top boxes,
Blu-ray players, game consoles, digital media players, hotel television systems and phones and other
network connected interactive devices that utilize television type display outputs. These devices allow
viewers to search, find and play videos, movies, photos and other content from the Web, on a cable TV
channel, on a satellite TV channel, or on a local storage drive.
NOTES
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Audio hardware / sound cards
A sound card provides stereo sound from your PC, through external speakers. It also allows for playback
of various audio format sounds, MIDI (Musical Instrument Digital Interface) sounds, and also allows you
to capture and record sounds from a microphone or other input device.
Most sound cards also will let you connect a game pad or joystick to the MIDI port, which doubles as a
joystick interface connector. If the sound card has a FireWire connector, it likely will allow you to
connect a digital video camcorder or even a webcam to it.
Sound cards come configured in PCI bus connector configurations, and all current technology cards are
designed to use a Plug-and-Play (PnP) format.
Many system boards have the sound card already built into them; users can choose to use the built-in
sound card, or install a better sound card into an existing PCI connection on the motherboard.
A sound card looks like what is pictured below; note the audio jack plugs (round), SCSI connection
(silver) and FireWire connector (gold) on the back of the card:
NOTES
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Communications hardware
Modems
A modem is a type of communications device that lets you connect your PC to another PC, or to the
Internet, via a connection to a traditional telephone line. Modems are limited in terms of the speed at
which they transmit data.
Current technology modems transmit up to 56,000 bits of data per second (Kbps); note that the Federal
Communications Commission (FCC) limits modem transmission speeds on phone lines to 53Kbps.
Modems have two RJ-11 style telephone jacks on them; one that connects to the wall jack, and one that
allows a telephone to be connected directly to the modem. The phone can be used normally while the
modem is NOT in use; when the modem is in use, the connection for the modem's telephone jack is
disabled.
Modems do NOT have an RJ-45 jack, which is found on a network interface card (or NIC). Conversely,
network interface cards do not have RJ-11 jacks on them. This is one way you can tell the difference
between a modem and a network interface card.
Dial-up modems have become obsolete, and should be used only if no other broadband
(high-speed) connections are available to the customer.
A modem looks like what is pictured below; note the two RJ-11 connectors on the back of the card:
"Cable modems" are actually a combination of a router and network interface card that transmits at least
10 megabits of data per second over what is normally either a cable television line or high-speed
telephone connection line. Cable modems are very popular in areas where broadband Internet access is
available, and such access is available in most parts of the United States at this time.
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Network Interface Cards (NICs)
A network interface card (NIC) lets you connect your computer to a network of other computers. Virtually
all network cards use twisted-pair network cable, which is an 8-wire multiple-line telephone-style cable.
NICs typically have only one RJ-45 connector jack in the back of them; RJ-45 jacks are larger than RJ-11
jacks, which are used for home telephone lines.
NICs are not attached to telephone connections, but to a hub or a router which allows data to be passed
between PCs on the network (or to the Internet).
Network interface cards transmit data at 10 megabit-per second (Mbit), 100, and 1000 Mbit speeds.
Most network cards have indicator lights on them to show a connection to the hub or router, and also the
speed at which the data is transmitted and received.
Many motherboards nowadays have network interface cards built into them, because the cost to include
them onto the board is so minimal.
Adapters do exist that will let you convert output from a USB port to an Ethernet connection. The author
generally recommends using an actual network interface card rather than one of these adapters, unless
there is no way to install such a card.
A network interface card looks like what is pictured below; note the RJ-45 connector and the link light
indicators on the back of the card:
NOTES
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Serial, parallel, USB and Firewire ports
PCs provide you with a number of input/output (I/O) ports that allow you to attach external devices such
as mice, printers and scanners. Below is a discussion of the major kinds of ports
Serial port
A serial port connects serial devices (mouse, modem, plotter, digitizer) to your computer; serial ports
send 1 bit of data at a time along a single data pathway, waiting for acknowledgment before sending
additional data. In this way, very accurate transfer of data can take place. Serial ports are male
connectors on the back of your computer, and have either 9 or 25 gold or silver pins in the connector, as
shown in the illustration below.
Parallel port
A parallel port connects parallel devices like a printer to computer; parallel ports send 8 bits of data (1
byte) at a time, rather than one bit of data at a time. Standard parallel ports (SPPs) transmit data
unidirectionally from the PC to the printer (or other device); enhanced parallel ports (EPPs) transmit data
in both directions. Enhanced communications ports (ECPs) transmit more data bi-directionally than do
enhanced parallel ports, because they add a direct memory access (DMA) channel of data transfer
capability to the port, which doubles the amount of data that can be transmitted through the port.
Parallel ports are female connectors on the back of your computer, and have a 25-socket connector, as
shown in the illustration below.
Universal Serial Bus (USB) ports (Versions 1, 2 and 3)
USB is a built-in feature of most current motherboard PC chip sets, as well as operating systems. Version
1.1 of the USB specification was released in January of 1996 by the USB Implementers Forum (USB-IF)
and was followed up by version 1.1 in September of 1998. A theoretical maximum of 127 devices per
controller is specified. Both versions 1.0 and 1.1 support a maximum transfer speed of 12 Megabits per
second (Mbps) and can fall back to a lower-speed 1.5Mbps if necessary.
USB version 2.0 was released in 2000, upping the theoretical maximum transfer rate by a factor of 14 to
480Mbps dubbed "Hi-Speed". USB 2.0 devices are backwards-compatible with USB 1.x devices and
controllers, and can fall back to 12Mbps or 1.5Mbps speed in order to coexist with older devices. Nearly
all new products on the market are USB 2.0-compatible.
Both USB 1.x and USB 2.0 allow the use of two separate types of connectors Type A and Type B
depending on the requirements of the device itself. Type A connectors are almost always used on the
host side (computer or hub), while Type B connectors are smaller and are frequently found on the device
side in printers, scanners, and other similar hardware.
Many PCs now use the USB interface as the primary way to connect both the keyboard and mouse.
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Both types of connectors can provide up to 500mA (milliamps) of power to connected devices, though
devices that require more than 100mA should be self-powered as each USB port generally has a
maximum of 500mA of power to share between all devices. A device that draws all of its required power
from the USB bus is referred to as a "bus-powered" device.
Version 1.0 of the USB 3.0 specification was completed in November 2008. The USB Implementers
Forum (USB-IF) manages the specifications and publishing the relevant technical documents necessary
to allow the world of developers and hardware manufacturers to develop products around the USB 3.0
protocol standard.
In summary, USB version 3.0 provides the following benefits over USB 2.0:
●
●
●
●
●
Higher transfer rates (up to 4.8 Gbps)
Increased maximum bus power and increased device current draw to better accommodate
power-hungry devices
New power management features
Full-duplex data transfers and support for new transfer types
New connectors and cables for higher speed data transfer...although they are backwards
compatible with USB 2.0 devices and computers
By eliminating add-in cards and separate power supplies, USB can help make PC peripheral devices
more affordable than they otherwise would be. In addition, USB's "hot-swapping" capability allows
business users to easily attach and detach peripherals. PCI-USB add-in cards provide an independent
USB bus to which even more peripherals can be connected.
A USB A-to-B cable connects from a PC or laptop (the “A” connector part of the cable) to a printer (the
“B” connector). USB micro and USB mini connectors attach to peripherals such as smartphones.
A USB connector looks like what is pictured below:
PS/2 port
Typical PC systems use PS/2-style connectors for both the keyboard and for the mouse, or they use USB
connectors for these devices. IBM designed this type of interface for their PS/2 computer systems, all of
which are now obsolete. Only the style of keyboard connector remains today. Many of these connectors
are now color-coded, so as to ensure that the keyboard is installed in the keyboard plug and the mouse
into the mouse plug.
Plugging a mouse into a keyboard port (or vice versa) will cause an error message to display on the
computer at power-up, even though the plug is firmly connected to the (wrong) connector.
A PS/2 connector looks like what is pictured below; the blue connector is for the keyboard, and the green
connector is for the mouse:
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Firewire ports
In December of 1995, the IEEE released an official Firewire specification, dubbed IEEE 1394. This
specification, sometimes referred to as 'Firewire 400', describes a hot-swappable peripheral interface
with transfer speeds of 100 Mbps, 200 Mbps, and 400 Mbps. During the late 1990s, this standard found
its way into Sony electronics (mainly digital camcorders) under the title 'i.LINK'. In January of 1999, Apple
released what was probably the first personal computer system to include Firewire ports by default: the
Blue PowerMac G3. All Macintosh models from then on have included Firewire connectivity.
Firewire cables come in two variations 4-pin and 6-pin. 6-pin cables provide up to 30V of power, allowing
for fully bus-powered devices. 4-pin cables do not provide power.
In April of 2002, the IEEE released an updated Firewire standard, dubbed IEEE 1394b. IEEE 1394b
allows for theoretical maximum transfer rates of up to 3.2Gbps. Apple commercially released a subset of
this new standard under the title 'Firewire 800' in 2003. Firewire 800 devices support a maximum
transfer speed of around 800Mbps. Firewire 800 adds a new cable type, using 9-pin cables (also called
'beta' cables), which support the full speed of Firewire 800. Firewire 800 is backwards-compatible with
Firewire 400 when 'bilingual' (9-pin to 6- or 4-pin) cables are used. Firewire 400 devices will still run at
Firewire 400 speeds, even when connected to a Firewire 800 host.
In general usage, USB-connected devices are well suited for peripherals such as printers, scanners, and
portable flash drives. Firewire is the preferred data transfer interface for digital imaging and video, and it
is a much faster interface for external storage devices such as hard drives and CD/DVD burners.
A Typical Firewire connector looks like what is pictured below:
Keyboards, mice and other input devices
Keyboards are the primary input device used on a typical computer. Most keyboards have between 101
and 104 keys, and have either a USB connector or a PS/2-style connector.
A mouse is the second-most important input device on a PC. It allows the user to manipulate icons,
features and text within a graphical user interface, or GUI. Mice typically have 2 buttons on them, and
most have a wheel that can be used to scroll down through text on a page on a document. Mice either
use a USB connection, or a PS/2-style connector identical to the keyboard connector.
Scanners are used to transfer text or images into a useable format on the PC. Scanners can use optical
character recognition (OCR) to translate a typed page into useable text for a word processing program,
and they can convert pictures into .JPG or similar picture format that can be used with programs such as
Microsoft Photo Editor. Scanners can attach to your PC through a USB connector, or via a parallel port,
serial port, or SCSI host adapter.
One also can attach webcams, barcode readers, smart card readers, or biometric readers to a PC,
usually to an available USB port. Software drivers may be needed to complete the installation process.
Preparing
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A Coursebook in PC Hardware, Maintenance & Repair
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William A. Lloyd
Thunderbolt cards
Thunderbolt is the brand name of a hardware interface that allows the connection of external
peripherals to a computer. Thunderbolt 1 and 2 use the same connector as Mini DisplayPort (MDP),
while Thunderbolt 3 uses USB Type-C. Thunderbolt cards and interfaces can be found on both Apple
and Intel PC-based hardware platforms.
It was initially developed and marketed under the name Light Peak, and first sold as part of a
consumer product on February 24, 2011. The Light Peak concept was co-developed by Apple and
Intel. Apple registered the name Thunderbolt as a trademark, but later transferred the mark to Intel,
which held overriding intellectual-property rights.
Thunderbolt combines PCI Express (PCIe) and DisplayPort (DP) into one serial signal, and additionally
provides DC power, all in one cable. Up to six peripherals may be supported by one connector through
various topologies.
Thunderbolt controllers multiplex one or more individual data lanes from connected PCIe and
DisplayPort devices for transmission via one duplex Thunderbolt lane, then de-multiplex them for use
by PCIe and DisplayPort devices on the other end. A single Thunderbolt port supports up to six
Thunderbolt devices via hubs or daisy chains; as many of these as the host has DP sources may be
Thunderbolt monitors.
An example of a Thunderbolt card and a Thunderbolt cable connection is shown below.
Thunderbolt card
Thunderbolt connector
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William A. Lloyd
Interrupt requests (IRQs), DMA channels and port addresses
Interrupt request levels (or IRQs) allow your PC to prioritize multiple accesses to the CPU. Virtually ALL
devices (i.e., network card, drive controller, sound card) will have an IRQ assignment.
DMA channels are dedicated high-speed data bus pathways on the motherboard of your PC that allow
data to travel from point A to point B within your PC. Devices like sound cards or old floppy drive
controllers will use a DMA channel to improve their performance.
Port addresses (also called an I/O address or I/O range) are like mailboxes; they are locations in
memory to which information is both picked up and dropped off. ALL devices will use at least one port
address, and no two devices can use the same port address.
If any of these above settings are incorrect, or if your device is using the same DMA channel or port
address value as some other device in your PC, your device (sound card, CD-ROM drive, fax modem)
will NOT function properly.
In earlier days of the computer era, a technician would have to set the proper IRQ, DMA and port address
values for a device (like a modem or network card) MANUALLY by setting switches or jumpers on the
card.
Today, all installed devices use plug-and-play technology and these IRQ, DMA channel and port address
values are set by software drivers created by the device manufacturer.
Here is a list of the standard interrupt levels and port addresses for parallel and serial ports:
TYPE OF PORT
IRQ NUMBER
PORT ADDRESS
SERIAL PORTS
COM 1:
IRQ 4
3F8 H
COM 2:
IRQ 3
2F8 H
COM 3:
IRQ 4
3E8 H
COM 4:
IRQ 3
2E8 H
PARALLEL PORTS
LPT 1:
IRQ 7
378 H
LPT 2:
IRQ 5
278 H
LPT 3:
IRQ 7, or 5, or NONE
3BC H
COM 1: and COM 3: share IRQ 4, and COM 2: and COM 4: share IRQ 3. However, these COM ports
each use unique port addresses, to make sure that each port is uniquely identified.
LPT 3: can share IRQ 7 or 5, but it MUST have a port address that is unique from LPT 1: or LPT 2:. In
some systems LPT 3: will operate with no IRQ level; your software package will need to know how to
directly address the port address being used for LPT 3:.
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Below is a chart that shows the standard interrupt settings for typical PCs, showing IRQs 0 through 15.
IRQ LEVEL
STANDARD DEVICE
ALTERNATE DEVICE
IRQ 0
System timer
None
IRQ 1
Keyboard controller
None
IRQ 2
2nd IRQ controller cascade
None
IRQ 3
COM2:
COM4:
IRQ 4
COM1:
COM3:
IRQ 5
Sound card
LPT2:
IRQ 6
Floppy disk controller
None
IRQ 7
LPT1:
LPT3:
IRQ 8
Real-time clock
None
IRQ 9
Cascaded to IRQ2
Network interface card
IRQ 10
Available
USB controller / NIC
IRQ 11
Available
SCSI host adapter
IRQ 12
PS/2 mouse port
NIC
IRQ 13
Math Coprocessor
None
IRQ 14
Primary IDE interface
None
IRQ 15
Secondary IDE interface
None
Generally on a PC, the higher the IRQ number, the higher priority is assigned to that device when there is
a contention for resources.
For example: if a PC locks up when you save a document, and you press CTRL-ALT-DEL on your
keyboard and nothing happens, it may be that the keyboard (operating at IRQ 1) does not have priority to
stop a process on your hard drive interface at IRQ 14.
A list of standard DMA channel assignments is found on the next page.
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Below is a chart that shows the standard DMA channel settings for typical PCs, showing DMA channels 0
through 7. The chart also shows which DMA channels are typically in use.
DMA CHANNEL
DEVICE USED
DATA TRANSFER
DMA 0
Available
8-Bit
DMA 1
Sound card
8-Bit
DMA 2
Floppy disk controller
8-Bit
DMA 3
Available
8-bit
DMA 4
1st DMA Controller cascade
16-bit
DMA 5
Sound card
16-bit
DMA 6
Available
16-bit
DMA 7
Available
16-bit
For the A+ examination, you will need to be able to answer the following kinds of questions:


What are the standard port address and IRQ settings for COM1: through COM4:, and also LPT1: through
LPT3:.
What are the standard IRQ and DMA channel assignments in a typical PC, as described in the previous
few pages?
NOTES
Preparing for A+ Certification: 2016 Edition
A Coursebook in PC Hardware, Maintenance & Repair
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Copyright, 2016
William A. Lloyd
Memory usage in the DOS - Windows ME environment [obsolete]
When running operating systems from DOS through Windows ME, memory has been subdivided into
several ranges: conventional memory, reserved (or upper) memory, and extended memory. The chart
below describes how memory is allocated on a typical PC with these obsolete operating systems.
NOTE: newer PCs and operating systems use advanced memory management techniques, so these
constraints do NOT apply with Windows 95 and above. This information will NOT be covered in the
current A+ examination; it is provided in the event you have to deal with an obsolete operating system.
This area of memory (Segment C) is referred to as the
Extended memory area. It is the area of memory
ABOVE 1 MB installed on your motherboard.
C
This area of memory is found in AT-class computers, including
286 through Pentium-class computers. It is NOT found in
old (obsolete) XT-class (8088) computers.
The program HIMEM.SYS must be loaded into memory in
order to access and use extended memory. The amount of
extended memory in your PC depends on the way your
motherboard is designed; check your hardware manual to
determine how much memory your PC will accept.
B
This area of memory (Segment B) is referred to as the
Reserved memory area. It is the area of memory between
640 KB and 1 MB. There is a memory block here that is 64K in
size which is used by expanded memory drivers for memory
swapping; it is called the EMS window. The rest of the area
is used by your video card, ROM BIOS, and other hardware
devices.
This area of memory (Segment A) is referred to as the
DOS/Conventional memory area. This area of memory begins
at 0K and ends at 640KB. All of your DOS programs run in
this area of memory primarily.
Windows programs use this area first also, and then they will
use extended (or expanded memory) as well.
A
DOS/Windows 9x is made up of three main boot files, and
two other files which you create. These files are listed below in
the order in which they load into memory:
a)
b)
c)
d)
e)
IO.SYS
MSDOS.SYS
CONFIG.SYS
COMMAND.COM
AUTOEXEC.BAT
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User-defined
User-defined
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William A. Lloyd
There is, in fact, another type of memory that is potentially used on an even OLDER PC: expanded
memory. By definition, expanded memory is always located on a separate card plugged into a bus
connection on the motherboard.
There are virtually no PCs currently in use today that actually have a separate memory card installed on
them. However, certain game programs require the use of expanded memory to run properly.
Microsoft provided a program that allows your extended memory to emulate expanded memory. This
program is called EMM386.EXE. It creates a 64k area in reserved memory called the EMS window.
Data is then passed from conventional memory, through the EMS window, into expanded memory in
64kb blocks. This process is relatively slow in comparison to what HIMEM.SYS does to allow the PC to
directly access extended memory.
The EMM386 driver is loaded via the CONFIG.SYS file as the PC boots up; the statement
DEVICE=C:\WINDOWS\EMM386.EXE will load the driver and cause extended memory to be used also
as expanded memory.
These divisions in memory become meaningless in a Windows 2000 and higher environment;
these operating systems were developed using the 80386 CPU as the minimum processor
capable of supporting the operating system.
Current technology processors and newer operating systems (such as Windows XP, Vista or Windows 7)
use advanced memory management techniques that make these arbitrary memory divisions much less
relevant to users and software/hardware developers.
By comparison, operating systems such as MS-DOS through Windows 9x have, as their minimum
processor, the old 8088 XT-class processor as the basis for operation. Although Windows 9x does not
operate on a system with less than an 80386SX processor, it still supports old DOS applications written
for the 8088 XT-class CPU. These classes of CPUs, and these operating systems, have long since
become obsolete.
Again, the A+ examinations no longer ask any questions concerning memory usage in the DOS
environment. This information only is provided so that if you encounter an older computer with memory
management issues, you will have some information to help you understand and resolve the problems.
Information on the boot sequence for Windows XP and above is found in Chapter 3 of this textbook.
NOTES
Preparing
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William A. Lloyd
Steps to preparing a hard disk for use in A PC
There are several distinct steps you must follow to prepare a hard disk for use in your PC, whether it is a
single hard drive or an additional drive being installed in the unit. These steps are listed below:
Detecting the hard drive in the CMOS Setup program
You first must go into the CMOS Setup program on the PC, and enter the hard disk specifications into
CMOS RAM, so that the PC will recognize, test and use the hard drive. The computer will not recognize
or use the hard drive until you enter the technical specifications for the drive into the computer's Setup
program, and store this information into CMOS RAM.
Typically you will use the auto-detection feature found in current-technology setup programs. The
Setup program will query any hard drive(s) properly connected to the IDE ribbon data cable or SATA
cable, obtaining the technical specifications contained in the drive’s “diagnostic cylinder.”
On older systems, you may need to enter these drive specifications manually. Specifically, you need to
enter the number of "cylinders" (concentric circles magnetically marked onto the hard drive), how many
read/write heads the drive has, and how many sectors per track the drive is divided into. The setup
program may want to know if there is a write-precompensation cylinder (used for buffering when writing
data to the disk), and also where the "landing zone" is located (where the heads are parked at power
down). All of these specifications normally are written on the label of the drive, and also are available from
the drive manufacturer's web site.
Save the changes you made to the CMOS Setup program, exit Setup, and then the PC will reboot.
Understanding the factory “low-level format” of the hard disk
Before you obtained the hard drive, the factory performed a "low-level" format on the device, so that the
disk controller can read and write to the physical media. The low-level format places the initial magnetic
markings throughout the disk, so that data can be accessed in a sequential fashion by the drive controller
(and any operating system you choose to use). If you have an IDE or SATA hard disk, you will NOT have
to low-level format the disk; this format is already done at the factory for you. Normally, you will never
perform a low-level format on IDE or SATA drives. Some IDE and SATA drives actually prevent
low-level formatting after leaving the factory. Most SCSI disks come low-level formatted from the factory,
but occasionally you may have to low-level format them in the field.
As mentioned above, you never will need to perform a low-level format of the hard drive in the field,
EXCEPT if some dire kind of problem has damaged the low-level format characteristics of the drive (like
some forms of aggressive viruses), or if there are serious problems reading or writing data to the drive.
Typically you would replace a drive that has problems with the low-level formatting, but sometimes that is
not an option. Additionally, you need a special program from the manufacturer (like Disk Manager,
Speedstor, Disk Technician, etc.) to perform the low-level format.
ONLY USE THE MANUFACTURER’S SPECIFIC PROGRAM to initiate a low-level format in the field.
If you must perform the low-level format on a hard drive, you will need to know the technical
specifications of the disk. Specifically, you will need to know the actual cylinder, head and
sector-per-track (SPT) values for that hard drive. You also may need to know the write precompensation
cylinder, the reduced write cylinder, and the landing zone location. You also will need to know at what rate
the hard drive controller should interleave the disk; interleave is the rate at which data is laid down in
sectors on the hard disk. All of the disk specifications can be found in your drive's manual, or on the drive
manufacturer's web site.
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Partitioning the hard drive
Next, you must partition the hard drive. The disk partitioning process places markings at the beginning
and end of the drive that tell any operating system how much disk space is available.
Typically a drive is partitioned as one single volume, but you can (for example) take a 500GB drive and
create two disk partitions (a C: and a D: partition) on the single device. Some professionals like this
approach; creating two partitions lets you use one for the operating system, and one for data (or another
operating system like Linux). Typically Windows and other Microsoft operating systems create one single
disk partition as the default behavior during the operating system installation process..
In the “old days,” if you were using MS-DOS 6.22 or below, or if you were using Windows 95 through
ME, you had to use the DOS program called FDISK to partition the disk. FDISK would partition the disk
and then create the logical drive letter assignment(s). FDISK allows you to divide your physical disk into
several logical drives, or just partition it into one single drive.
Also, if you were using the old OSR 2 version of Windows 95, Windows 98 or Windows ME, FDISK
would let you partition a hard disk of virtually any size (up to 4 terabytes) as one single partition, using
the FAT32 file system. Older versions of FDISK would only allow a partition size of up to 2 GB, because
it used the FAT16 file system. If you could not get FDISK to recognize your entire hard drive, you likely
had an older version of FDISK, and you would need to use a newer version of version of the program.
With Windows 2000 and above, the installation CD (or DVD) automates the disk partitioning and
formatting process. By answering the prompts in the Windows installation setup program, the hard disk
by default will be partitioned to use the full amount of available space on the drive. You can specify a
smaller amount of disk space than the maximum size, if you wish, during this process.
Formatting the hard drive
Finally, you have to perform the operating-system-level format of the drive. This process uses the
magnetic markings laid down on the disk surface during the factory low-level format. It creates a file
allocation table / master file table and the master boot record on the disk, and then it verifies that the disk
space is capable of storing data safely.
In the “old days,” if you were using MS-DOS 6.22 or below, or if you were using Windows 95 through
Windows ME, you would use the DOS program called FORMAT to perform this operation. After you ran
FDISK to partition the drive, you would enter the following command from the A:\ prompt:
FORMAT C: /S /V [Press Enter]
This command formats the disk, puts the DOS system files on it (so that it would become bootable), and
the /V switch allows you to put a name on the disk. Note that this process is now obsolete with the
advent of newer operating systems.
With Windows 2000 and above, the installation CD (or DVD) automates the disk formatting process.
You may be prompted to select the type of file system to use (either FAT32 or NTFS). In most cases
NTFS should be used, as it is the native file system for Windows 2000 and above. You also will be
prompted to select the typical full format option, or the quick format option.
A traditional full disk format on a larger drive (anything bigger than 100GB) could take upwards of 30
minutes to complete, and much larger drives will take quite some time to format. If you have a
brand-new hard drive, or a drive that you believe is in good condition, use the quick format
option. A quick format typically takes less than 30 seconds to complete, even on very large drives.
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Loading the operating system on the drive
Finally, you must load the Windows operating system onto the disk, so that the computer will have the
necessary interface for you to run the PC.
With Windows 2000 and above, Windows will be installed immediately after the disk partitioning and
formatting is completed. The installation process for Windows should take between 20 and 45 minutes to
complete, depending upon the speed of the processor, the amount of RAM in the PC, and the version of
Windows being installed. Newer versions of Windows take up more disk space and have more operating
system features, and will take longer to install than previous versions.
Once you have done these things, you will have a usable hard disk in your computer.
Adding a second hard drive to an existing system
If you have installed a second hard drive into the PC (to provide additional disk space), you will need to do
the following things:
●
●
●
Ensure that each of the two drives have the master-slave jumpers configured correctly (for IDE
drives), or the ID and disk termination jumpers set correctly for SCSI drives (note that SATA
drives need no jumpers to be configured properly);
Detect the second hard drive in the CMOS Setup program, as was done for the first drive; and
Partition and format the drive using the Disk Management tool in the Management Console
You do NOT need to reinstall the operating system when adding a second hard drive. The existing
operating system on the first drive will give you all the necessary tools to partition and format the second
drive.
With Windows 2000 and above, you will use the Disk Management application to partition and format
the second drive. Right-click on My Computer, and select the Manage option from the drop-down menu.
In the Microsoft Management Console window, click on the Disk Management option. In the dialog box
that appears, right-click on the unpartitioned disk, and select the Partition Disk (or Prepare Disk) option.
The disk partitioning (or preparation) wizard will guide you through the partitioning and formatting
process. Use the Quick Format option when formatting the second drive.
If you need to partition and format an external hard disk connected to your PC through a USB or FireWire
connection, the process is the same as the one described in the previous paragraph. The only difference
you will notice in partitioning and formatting an external USB/FireWire hard drive is that the drive does
not need to be detected in the CMOS Setup program.
Once the drive is connected to the USB or FireWire connection and is recognized by Windows, you then
can use the Disk Management application to prepare the drive.
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Classroom boot disks for use in lab sessions
We have bootable copies of the Windows Vista, Windows 7 and Windows 10 installation CDs (or DVDs)
available for student use during the lab sections. Also during the lab sections, we may re-image a
number of computers using the Ghost or Clonezilla applications.
We will provide you with bootable Ghost CDs to perform this work.
Please request one of these disks from the lab staff if you need a copy of these bootable disks.
For the A+ examination, you will need to be able to answer the following kinds of questions:
●
●
●
●
●
●
●
What are the steps involved in preparing a hard drive for use?
How do you partition a hard disk in Windows 2000 and above?
What is a partition table, and how is it created?
How would you use the FORMAT command to prepare a disk for use?
How do you format a hard disk in Windows 2000 and above?
How do you format a second hard disk in Windows 2000 and above?
How do you install an operating system onto a hard disk (for any of the operating systems
mentioned above)?
NOTES
Preparing
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Copyright, 2016
William A. Lloyd
Chapter 3. Overview of BIOS, POST, CMOS Setup Programs and Error Codes
The motherboard’s Basic Input-Output System, or BIOS, is contained in a read-only memory (ROM) chip. It
is the ROM BIOS that makes your computer IBM-compatible. It provides hardware recognition and
compatibility support, and also a method for testing your PC prior to your using it.
POST is the Power-On Self-Test, which your computer performs every time you turn it on and/or reboot it.
ALL IBM-compatible PCs perform this same type of test at power-up, in the same order as what was done
with the original IBM PC. This test ensures that all of the major components of the PC are working properly
before the user begins to perform normal operations with it.
The POST program is built into the ROM BIOS on your PC's motherboard. When power is applied to your
PC, the CPU resets itself, clears out any leftover or miscellaneous data, and looks to an address in
memory called F000; this is where the ROM BIOS is located in the PC's memory map. The CPU executes
the first program in the ROM BIOS' memory, and that program is the POST.
In order to do a comprehensive check on your PC, the ROM BIOS requires specific information about the
exact types of components installed on your PC. In particular, it needs to know the types of floppy and hard
drives which are installed, the type of video card, the amount of RAM, the date and time, as well as other
information related to how the PC should load the operating system. Most BIOS products will scan your
system and automatically identify the type of hard drive, type of optical drive, amount of RAM, and other
components installed on your PC.
You (or the technician who built your PC) needs to input this information into the SETUP PROGRAM; this
program is also built into the ROM BIOS chip along with the POST. You can access this Setup program by
pressing a combination of keys (i.e., Control-Alt-Escape, the Delete key, F1 or F2, and so on) when
prompted during the POST. When you turn on the PC, the proper keystroke to enter the Setup program will
be displayed briefly. These programs are fairly intuitive, and one can navigate through the program by using
the arrow keys, the Enter key to select options, and the Escape key to back up one level.
The information needed by the POST to accurately check your system is stored into a special RAM chip on
the motherboard called CMOS RAM. CMOS stands for Complementary Metal-Oxide Semiconductor; this
type of RAM chip will hold information if a small quantity of electricity is delivered to it.
To accommodate this, a small battery is attached to every IBM-compatible motherboard. This has been the
case from the early 80286-based systems on through motherboards being built today. These batteries
deliver enough electricity to the CMOS chip so that it retains the PC configuration information stored in it,
even when the power to the PC has been turned off or disconnected.
These batteries that power the CMOS chips have a life span of anywhere between 2 and 5 years. When the
batteries die, they need to be replaced. These batteries usually cost less than $10.00 at a computer retailer,
office supplies outlet, electronics store or computer show.
Further, the information in the CMOS RAM vanishes when the battery dies, and the table of system
configuration stored in CMOS needs to be updated before the computer will operate properly.
This does NOT mean that you have lost any of the information on your hard disk; it only means that you
cannot access the data on the hard disk UNTIL you re-enter the information in CMOS RAM, so that the PC
can test and recognize each device.
Once you re-run the Setup program and enter the correct information for the kinds of components inside
your computer, the system will return to normal, and all of the devices in your PC will work as expected.
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UEFI BIOS Products
As computers and operating systems have become more complex and capable of accessing larger amounts
of RAM and disk space, motherboard BIOS products have had to adapt.
The UEFI (Unified Extensible Firmware Interface) is a standard firmware interface for PCs, designed to
replace BIOS (basic input/output system). This standard was created by over 140 technology companies as
part of the UEFI consortium, including Microsoft. It's designed to improve software interoperability and
address limitations of BIOS. Some advantages of UEFI firmware include:
• Better security by helping to protect the pre-startup—or pre-boot—process against bootkit/rootkit attacks
• Faster startup times and resuming from hibernation
• Support for drives larger than 2.2 terabytes (TB)
• Support for modern 64-bit firmware device drivers that the system can use to address more than 17.2
billion gigabytes (GB) of memory during startup
• Capability to use BIOS with UEFI hardware
UEFI BIOS provides a software interface between an operating system and platform firmware. UEFI
replaces the traditional BIOS firmware interface originally present in all IBM PC-compatible personal
computers with most UEFI firmware implementations providing legacy support for BIOS services. UEFI can
support remote diagnostics and repair of computers, even with no operating system installed.
UEFI requires the firmware and operating system loader (or kernel) to be size-matched; for example, a 64bit UEFI firmware implementation can load only a 64-bit operating system boot loader or kernel. After the
system transitions from "Boot Services" to "Runtime Services", the operating system kernel takes over. UEFI
BIOS is supported by Microsoft and Linux operating systems.
In addition to the standard PC disk partitioning scheme that uses a master boot record (MBR), UEFI also
works with a new partitioning scheme called the Globally Unique Identifier (GUID) Partition Table, or GPT,
which is free from many of the limitations of the MBR. In particular, the MBR limits on the number and size of
disk partitions (up to four primary partitions per disk, and up to 2 TiB (2 × 240 bytes) per disk) are relaxed.
The GPT allows for a maximum disk and partition size of 8 ZiB (8 × 270 bytes).
Unlike BIOS, UEFI does not rely on a boot sector, defining instead a boot manager as part of the UEFI
specification. When a computer is powered on, the boot manager checks the boot configuration and, based
on its settings, loads and executes the specified operating system loader or operating system kernel. The
boot configuration is a set of global-scope variables stored in NVRAM, including the boot variables that
indicate the paths to operating system loaders or kernels, which as a component class of UEFI applications
are stored as files on the firmware-accessible EFI System partition (ESP).
Operating system loaders can be automatically detected by a UEFI implementation, which enables easy
booting from removable devices such as USB flash drives. This automated detection relies on a
standardized file path to the operating system loader, with the path depending on the computer architecture.
Windows 8 became one of the first operating systems to employ UEFI booting.
Booting UEFI systems from GPT-partitioned disks is commonly called UEFI-GPT booting. It is also common
for a UEFI implementation to include a menu-based user interface to the boot manager, allowing the user to
manually select the desired operating system (or system utility) from a list of available boot options.
UEFI is, in many ways, like a miniature operating system. Because of that, hackers are developing malicious
software that can corrupt the BIOS. This can create serious problems that can render a PC useless.
Keeping your UEFI BIOS up-to-date with the latest version from the manufacturer will protect you from
potential problems. More will be discussed about this issue later in the textbook.
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BIOS-based system monitoring
In addition to the changes to the system board ROM BIOS brought on with UEFI, there are other changes to
BIOS that will help the customer and technician.
Many new BIOS products will allow you to monitor the temperature of the CPU and other motherboard
components. You can adjust the fan speed for the CPU and other case-mounted cooling fans. On some
computers, the addition of an “intrusion detection” switch will let the technician know where the computer
has been tampered with prior to servicing. Voltage, CPU clock speed and front-side bus speeds can be
changed, if the customer wishes to over-clock their system.
These features vary between different motherboard manufacturers. You will need to check the
documentation that came with the board, or visit the manufacturer’s website, in order to determine which
features are included in the board, and how those features can be manipulated.
Accessing and configuring the CMOS Setup program
So, HOW do you know how to properly run this setup program?
First, gather all the available documentation about your computer. Specifically, what are the exact
specifications of your hard disk, how much RAM has been installed, what type of floppy drive is installed,
and so forth.
Next, locate the owner's manual and see if there is any information in it on how to correctly run the Setup
program, and what may be the default settings that ensure proper operation of the computer. You may also
want to contact the manufacturer’s technical support area, or contact a computer technician that can instruct
you on how to run the program properly.
You can access the CMOS setup program when as the PC is going through POST by pressing a certain key
(or set of keys) when prompted on the screen.
Many setup programs are accessed by pressing the Delete key, or Ctrl-Alt-Esc together, or the F1
key, or the F2 key, or the F10 key. Watch the monitor screen to see which key to press.
Pressing the Delete key gets you into the setup program for AMI and Award BIOS. Phoenix BIOS uses the
F1 key, or F2, or Ctrl-Alt-Esc, or Ctrl-Alt-S. Dell computers usually use the F2 key to access the setup
program, while HP/Compaq computers use the F2 or F10 key. Check the system documentation to see
which keystroke sequence will let you access the setup program.
If you have BIOS from another manufacturer, look at the screen during POST for a message explaining
what keystroke you should use to enter the setup program. If there is no message on the screen, consult the
system documentation for how to access the setup program.
Standard Setup
Here is where you will set date, time, floppy/hard drive types, video type, and memory size. You also may be
able to set the hard drive auto-detection feature either to on or off. On is the default setting.
Use the left/right arrow keys to move from field to field on the screen. Use the Page Up/Page Down keys, or
the plus/minus keys to modify the values in each field. The Enter and Esc keys move you up or down one
level within the setup program. These rules apply in virtually all setup program screens.
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Advanced/Extended Setup
The advanced setup lets you set the boot sequence, or perform a full or partial memory test, or
enable/disable shadow RAM, or enable/disable cache memory, or enable features like block mode and LBA
mode, or to set wait states on the CPU or memory.
If you don't know how to set up these features, there should be a keystroke you can press that reloads the
factory default settings (look at the bottom of the screen for details). You can try modifying different settings
to get better performance on your PC. There is no magic formula ... trial and error works best. Refer to the
system board documentation for guidelines on how to set these features.
Integrated Peripherals
Virtually all motherboards have the drive interfaces, video cards, and I/O ports built into the motherboard.
This portion of the setup program lets you enable or disable any of these built-in devices.
IDE or SATA HDD Auto-detect
This feature allows you to read the drive parameters from the IDE or SATA hard drive's diagnostic cylinder
into the setup program. Use this feature to input the drive specifications, and to assure that the drive is
connected and functioning properly.
Virtually all manufacturers now use auto-detection to determine a hard drive’s technical specifications. Make
sure the setting in these programs is set to the “Auto” feature; if the setup program shows the value here as
“Off,” a hard drive will not be recognized until it is changed back to Auto.
Power Management (Green) features
This option allows you to enable features that shut down certain PC components after a set period of
inactivity. You can select which devices get powered-down and when in this screen.
You can configure the power management features within the CMOS Setup program and also within the
Windows operating system. Below is a list of the key features, and how they differ one from another:
Suspend mode: this feature causes the system to enter a low-power state. Information on system
configuration, open applications, and active files is stored in main memory (RAM), while most of the
system's other components are turned off. A system in suspend mode can use as little as 5 watts of power,
with most of it going to main memory for data maintenance.
If left in suspend mode, a system may be programmed to waken, so it can perform tasks at any given time.
If the power is interrupted, then the system will undergo a normal reboot, restoring full power to the machine
and losing any information not saved to the hard disk.
Wake on LAN: Many times, IT personnel prefer to maintain client systems after the employees have gone
home. Even if these tasks are automated, client machines must be left on. In the past, if they were not left
on, personnel had to manually turn them on. With the wake-on-LAN feature, client systems can be remotely
and automatically powered up.
Wake-on-LAN technology resides in a PC's managed network adapter and motherboard. The two are
attached via a wake-on-LAN cable terminated by a three-pin connector on each side.
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When the system is turned off, the managed network adapter uses an alternate power source to monitor the
network and watch for a wake-up packet from the server. Once it receives a packet, it alerts the system to
power up and accept any maintenance task it is given.
Wake-on-LAN is a part of Intel's Wired for Management System and is a result of the Intel-IBM Advanced
Manageability Alliance. Wake-on-LAN is also called remote wake-up.
Sleep timers: this energy-saving mode shuts down all unnecessary components after a certain period of
inactivity. Many battery-operated devices, such as notebook computers, support a sleep mode. For example,
when a notebook computer goes into sleep mode, it shuts down the display screen and disk drive.
Once awakened, the computer returns to its former operating status. Windows allows you to set the sleep
timers for the display, hard drive, and the main system. For the main system timer, the computer can go
either into suspend mode or into hibernation mode.
These sleep timers work together with your operating system and your ROM BIOS to produce these
energy savings. Two of these modes, hibernation and standby, are discussed below.
Hibernation mode: this power management mode conserves electricity by powering down the system. In
hibernate mode the current state of the system is saved to the hard drive, and the system will power down.
When a user turns the system power back on, the saved information is read from the hard disk, restoring the
last used settings. Hibernation mode is similar to sleep mode, however in sleep mode the power cannot be
shut off.
Hibernation mode can be problematic, however. If a system loses power while creating the hibernation file,
there is a distinct possibility that some form of disk data loss can occur. The author, as a rule, discourages
the use of hibernation, because of this issue,
Standby mode: Similar to suspend mode, standby mode switches your entire computer to a low-power
state (when it is idle) where devices, such as the monitor and hard disks, turn off and your computer uses
less power. When you want to use the computer again, it comes out of standby quickly, and your desktop is
restored exactly as you left it.
Standby mode is particularly useful for conserving battery power in portable computers. Because Standby
does not save your desktop state to disk, a power failure while on Standby can cause you to lose unsaved
information.
Exiting the Setup Program
You can save the values you have just changed, or you can exit the program without saving the changes.
Both options should be apparent to you on the main setup program screen. When you select to exit the
setup program, the computer will reboot.
For the A+ examination, you will need to be able to answer the following kinds of questions:
•
•
What can be set up in the CMOS setup program, and what are the major features in a
CMOS setup program?
How do I access a CMOS setup program; which keystrokes will let me run Setup?
NOTES
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The Power-On Self-Test, and error codes / error messages
Below is a chart that lists exactly what the Power-On Self-Test (POST) checks; these checks are the
same on ALL brands of IBM-compatible computers.
100 Series:
200 Series:
300 Series:
400 Series:
500 Series:
600 Series:
700 Series:
900-1000 Series:
1100-1200 Series:
1300 Series:
1400 Series:
1700 Series:
Motherboard checks
Memory chip checks
Keyboard checks
Monochrome monitor checks
Color monitor (CGA) checks
Floppy Disk Drive checks
Math Co-processor checks
Parallel Port Adapter Checks
Serial Port Adapter Checks
Game Port Adapter Checks
Printer Checks
Hard Disk/Disk Controller Checks
If something is wrong with your computer, an error code will be displayed on the top of your screen. For
example, any error between 201 and 299 means that there is a problem with your RAM memory; any
error between 601 and 699 means there is a problem with your floppy disk drive and/or floppy disk
controller. You will be prompted to press the "F1" key to continue booting the computer; normally, you will
want to power-down the PC and repair the problem before continuing to use it.
On newer computers, these error codes may be replaced with English-language error messages, such as
“Keyboard error or no keyboard present.” However, many manufacturers still use error code messages to
report hardware problems. This forces the consumer to haul the computer into the repair shop, because
they do not understand the meaning of the error codes. On the course DVD, there is an exhaustive list of
IBM-compatible error codes and what each code means. For the A+ examination, you simply need to
memorize the major error code categories shown in the list above.
What happens if the computer just beeps at you?
You may also hear a series of beeps when you turn on the computer, IF SOMETHING IS WRONG.
Normally, you hear only one short beep. The one short beep (or two short beeps if you have a Compaq
computer), indicates that the POST has completed, and it found no hardware errors with the tested
components.
If there are hardware problems AND the PC cannot display an error code or message to the screen, the
computer will beep in a predefined series of beeps to indicate exactly what is wrong with your PC. This
beeping is not random, and it can instruct you about exactly what is wrong with your PC.
Here are some of what the most common DOS Audio Error codes mean:
No display, no beeps:
No power
Continuous beep:
Repeating short beeps:
Power supply failure
Power supply failure
Two beeps:
Unspecified problem; read message on screen for further
details (such as keyboard error, drive misconfiguration)
One long and two short
beeps (or three short beeps,
or eight short beeps):
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Different manufacturers of PCs and BIOS chips have differing sets of beep codes, some having more
extensive beep codes than others. Phoenix BIOS has the most extensive set of beep error codes, but
AMI BIOS and Award BIOS have a long list of beep codes.
Depending upon your motherboard and BIOS manufacturer, a series of beeps may mean different
things. You will need to check the documentation for a given system, or visit the manufacturer’s
website, in order to decipher the meaning of a given beep code sequence.
The BIOS Companion reference book has an extensive list of PC error codes, listed by ROM BIOS
manufacturer and PC manufacturers. Also, the websites for the major BIOS manufacturers (such as
AMI, Award and Phoenix) have this same information available upon them.
For the A+ examination, you will need to be able to answer the following kinds of questions:
•
•
What does POST stand for, and what does it do?
What are the major ranges of error codes? For example, an error code between 301 and 399
indicates an error with exactly WHAT on your computer? (Hint: you type on it …)
NOTES
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Steps in the Windows boot process
The following is a description of what happens to your PC, from the time that you turn it on to the time that
is finished booting up the operating system. The first example applies to computers running the
Microsoft Windows operating system (Windows NT through Windows 10).
1)
When the PC is powered up, the CPU resets itself, clears out any left-over data, and looks to an
address in memory called F000 ...that is where the ROM BIOS chip is located. The ROM BIOS
chip is what makes your PC IBM-compatible. When the CPU finds the ROM BIOS chip, it invokes
the first program found in memory, which is POST: the Power-On Self-Test. This self-test ensures
that all of your components are operating properly BEFORE you begin working with the computer.
2)
As POST checks your computer, it looks to a record of data stored in CMOS RAM that tells what
kinds of components are in your PC. Specifically, it records what type of video card, floppy drives,
hard disk, memory and so forth are contained in your PC. POST will test your computer based on
what it believes is in your PC. If the information is missing or incorrect, the PC will not recognize or
use certain components in your system. It is important to keep a record of what specifically is
inside your computer, and that you have a record of what is written into CMOS RAM.
3)
If POST finds that there is a problem with your PC, it will display an error message or an error
code that tells specifically what is wrong with the unit. If it cannot display such a message, it will
beep in a specific pattern that indicates exactly what is wrong. If everything is OK with the
computer, POST will sound one beep to the system speaker, indicating that all of the tests passed
normally with no errors.
4)
The ROM BIOS will then look to the boot sector of either a floppy disk or a hard disk to find the
boot loader program of your operating system. If it cannot find this file in that location, the PC will
give an error message to the screen. When it does find the file, it loads the file into RAM, and then
your operating system takes charge of the computer. NTLDR is the boot loader program for
Windows NT through Windows 10. Linux uses a program called GRUB to begin its boot process;
this will be discussed further on the next page.
5)
Windows then loads the files called BOOT. INI, NTDETECT.COM, NTOSKRNL.EXE, SYSTEM
and HAL.DLL to bring up the operating system. BOOT.INI is used whenever you have multiple
operating systems to boot your PC. NTDETECT.COM detects the various hardware devices in
the PC. NTOSKRNL is the operating system kernel, which contains the majority of the operating
system instructions. SYSTEM and HAL.DLL customize Windows to operate on any given PC.
Every PC will have different hardware configurations, and these programs ensure that Windows
will look and work the same on all platforms.
6)
Then, WINLOGON.EXE and EXPLORER.EXE are loaded; these programs provide the user
interface common to Windows, and also allow you as a user to log onto the system.
If any of these steps do not occur in a normal manner, your PC may not boot up as you would expect.
Knowing the steps in the boot process will help you when trouble-shooting or analyzing problems with
your PC.
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This is what happens when a computer boots up using a Linux operating system; the Linux boot
process is more complex than with Windows operating systems. The first four steps, however, are
the same as with Windows:
1)
When the PC is powered up, the CPU resets itself, clears out any left-over data, and looks to an
address in memory called F000 ...that is where the ROM BIOS chip is located. The ROM BIOS
chip is what makes your PC IBM-compatible. When the CPU finds the ROM BIOS chip, it invokes
the first program found in memory, which is POST: the Power-On Self-Test. This self-test ensures
that all of your components are operating properly BEFORE you begin working with the computer.
2)
As POST checks your computer, it looks to a record of data stored in CMOS RAM that tells what
kinds of components are in your PC. Specifically, it records what type of video card, floppy drives,
hard disk, memory and so forth are contained in your PC. POST will test your computer based on
what it believes is in your PC. If the information is missing or incorrect, the PC will not recognize or
use certain components in your system. It is important to keep a record of what specifically is
inside your computer, and that you have a record of what is written into CMOS RAM.
3)
If POST finds that there is a problem with your PC, it will display an error message or an error
code that tells specifically what is wrong with the unit. If it cannot display such a message, it will
beep in a specific pattern that indicates exactly what is wrong. If everything is OK with the
computer, POST will sound one beep to the system speaker, indicating that all of the tests passed
normally with no errors.
4)
The ROM BIOS will then look to the boot sector of either a floppy disk or a hard disk to find the
boot loader program of your operating system. If it cannot find this file in that location, the PC will
give an error message to the screen. When it does find the file, it loads the file into RAM, and then
your operating system takes charge of the computer. Linux uses a program called GRUB to
begin its boot process. GRUB stands for the Grand Unified Boot Loader.
5)
When GRUB begins, it loads the kernel (the heart of the operating system) in three stages:
GRUB stage 1:
The primary boot loader takes up less than 512 bytes of disk space in the MBR, which is too
small a space to contain the instructions necessary to load a complex operating system.
Instead the primary boot loader performs the function of loading either the stage 1.5 or stage
2 boot loader.
GRUB Stage 1.5:
Stage 1 can load the stage 2 directly, but it is normally set up to load the stage 1.5. This can
happen when the /boot partition is situated beyond the 1024 cylinder head of the hard drive.
GRUB Stage 1.5 is located in the first 30 KB of Hard Disk immediately after MBR and before
the first partition. This space is utilized to store file system drivers and modules.
This enables stage 1.5 to proceed to stage 2 and load from any known location on the file
system (i.e., from a folder called /boot/grub).
GRUB Stage 2:
This is responsible for loading kernel from /boot/grub/grub.conf and any other modules
needed to run the operating system. It then loads a GUI interface or a splash image (located
at /grub/splash.xpm.gz) with list of available kernels where you can manually select the kernel
to use, or else after the default timeout value the selected kernel will boot. The original file is
called /etc/grub.conf, of which you can observe a symlink file at /boot/grub/grub.conf.
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6)
The kernel then is loaded in the following stages:







7)
The kernel, as soon as it is loaded, configures hardware and memory allocated to
the system.
Next, it uncompresses the disk image called initrd (compressed using zlib into
zImage or bzImage formats) and mounts it and loads all the necessary drivers.
The loading and unloading of kernel modules is done with the help of programs like
insmod and rmmod which are contained in the initrd image.
The kernel determines your hard disk types be it a LVM or RAID.
It unmounts the initrd image and frees up all the memory occupied by the disk
image.
Then the kernel mounts the root partition as specified in the file called grub.conf as
read-only.
Finally, it runs something called the init process.
The initialization process called init instructs the operating system to boot into a specific run
level, as specified in a file called /etc/inittab. Run levels are numbered, and indicate how Linux
should be operating; for example:
0 - halt (Do NOT set initdefault to this)
1 - Single user mode
2 - Multiuser, without NFS (The same as option 3, if you do not have networking)
3 - Full multiuser mode
4 - unused
5 - X11 (graphical mode)
6 - reboot (Do NOT set initdefault to this)
8)
Next, the file system's integrity is checked (by looking at the information contained in a file
called fstab), and the root partition is re-mounted in read-write mode (earlier the partition was
mounted as read-only). Runlevel scripts then will be executed that will launch specific startup
scripts, which are specific to different user-level accounts for that computer.
9)
If everything works as designed, the user will see the Login Screen on their system. You can
login either in non-graphical (or text) mode or graphical mode. Graphical mode gives you a
point-and-click user interface, whereas non-graphical text mode forces you to type commands
at the Linux prompt.
For the A+ examination, you will need to be able to answer the following kinds of questions:
•
What are the steps in the boot process for Windows and Linux, what files are loaded into
memory during boot-up, and in what order do these files load?
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Troubleshooting BIOS and CMOS Setup-related problems
The BIOS setup program on most PCs is intended to allow the user to easily and quickly set up the most
important parameters necessary for the POST (Power-On Self-Test) to run correctly. Most of these types
of things can be set by an average PC technician without great difficulty. However, there are a number of
BIOS Setup issues that are not quite so straight forward.
For example, the Advanced CMOS Setup allows you to enable things like built-in virus protection,
shadow RAM regions, boot sequences, RAM timing and wait states, and so forth. The Plug-and-Play and
PCI Configuration Setup lets you set how PCI bus connections and devices should operate, whether you
have installed a Plug-and-Play compatible operating system, and so forth.
Each motherboard's settings and options may be different, and depending upon the motherboard
"chipset" you have (the set of IRQ, DMA, and keyboard controllers that are permanently mounted onto
the system board), different revisions of the same board or BIOS may have different features.
The motherboard chipset, also referred to as the “Northbridge” and “Southbridge” chips, perform specific
input-output management tasks:
●
●
The Northbridge chip synchronously controls the flow of data between the CPU and the system
RAM.
The Southbridge chip controls the flow of data between devices plugged into the bus connectors
on the motherboard (PCI) and the Northbridge chip.
So HOW do you set a motherboard up correctly, or for maximum performance?
Documentation
Before attempting to modify any "non-standard" parameters of a CMOS setup program, you should
consult the documentation that came with the system board. If there is no documentation available, at
least go to the web site for the BIOS manufacturer and attempt to locate some helpful information about
that board, and the revision level of the BIOS chip.
Here are the web addresses for some of the major BIOS manufacturers:
Award: www.award.com
Phoenix: www.phoenix.com
Microid Research: www.mrbios.com
AMI: www.ami.com
Obtain any documentation about the product before making any changes, if possible.
Recordation
Make a paper record of what the BIOS settings are for each sub-section of the setup program BEFORE
you begin tinkering with the settings. At least this way, you will be able to get back to square one if you
make any mistakes in working with the setup program.
You may be able to print out a copy of each of these sub-sections by using the PrintScreen (or Shift PrintScreen) button on your keyboard. Try printing out these settings before going to the trouble of writing
them down on a piece of paper.
There are also utilities that let you save the CMOS values to a disk file, and then restore those values by
booting from a floppy disk and running the restore program for the CMOS values. See your instructor for
details on how to obtain such a utility for yourself.
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Experimentation
It has been said that experimentation is the basis for all good research. This instance is no different. In
order to find the maximum level of performance for your BIOS and chipset, you will have to tweak the
settings, reboot the computer, and see what happens. If it works, then bravo ... if it does not, then go back
and undo that change you just made. The key is: make only one change at a time, in order to make sure
that you can analyze correctly the improvement or impairment of the system's performance.
With some BIOS products, there will be a selection in the Setup program that allows you to choose the
"original" settings from the manufacturer, the "optimal" settings, or the "fail-safe" settings from the
manufacturer. You may want to try these options in the Setup program, and notice what changes were
made in each sub-section of the program, before venturing out on your own.
By the way, DO NOT PUT ANY PASSWORDS INTO THE SETUP PROGRAM UNLESS ABSOLUTELY
NECESSARY. You may be able to clear the password (and all the rest of the CMOS data) by temporarily
moving a jumper on the system board or removing the CMOS battery. But if you cannot do that, you may
be stuck with a system board that has a password that you cannot eliminate, ESPECIALLY when you
have forgotten the password. The password can prevent BOTH your booting to the operating system
AND entering the CMOS Setup program as well. This is especially true with laptop computers. There are
better ways of safeguarding your data than with a CMOS password.
Education
The Expert's Creed is stated as follows: Ask the one who has the experience. Many local vendors have
been doing BIOS troubleshooting and configuring longer than you have, so it pays to consult them for
their advice. Your presence here in this class is testimony to this idea. Once you have done the job of
CMOS configuration several (or more) times, you will learn (as the experts have) that there are certain
features that always should be turned on or off in a CMOS setup program (i.e., setting PCI configuration
to Auto, making sure the shadow RAM settings are correct, turning off the Boot sector virus protection
before installing your operating system, etc.).
The more you do this kind of work, the more you experiment, the better you will get at this process. Start
by asking your local parts supplier or computer guru a question like:
"Is there anything I should know about setting up this system board before I buy it?"
Standard and Advanced CMOS Setup Options
The Standard CMOS Setup program in all BIOS products allows you to input the most critical
specifications for your computer, such as the floppy drive types, the hard drive auto-detection feature, the
date, the time, the memory size, and so forth. Anyone with a minimum of repair training can input this
information with little difficulty. The information in this segment of the setup program, especially the hard
drive parameters, must be exact and correct, or else the device(s) will not be recognized or work properly.
If the hard drive device type is set to "Not Installed", the drive will not be recognized.
The Advanced CMOS Setup allows you to manipulate other issues that relate to booting correctly and
speed optimization. This includes such things as setting the boot sequence (Optical drive then C:, or C:
then network, etc.), enabling specific shadow RAM ranges, enabling boot sector virus protection,
enabling a floppy drive seek at boot time, enabling cache memory (both external and internal CPU
caches), enabling the quick or full Power-On Self-Test (POST), system CPU speed, enabling RAM
parity checking, and various password checking options.
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Advanced Chipset Setup Options
The Advanced Chipset Setup options allow you to control the motherboard chipset (DMA and IRQ
controllers, keyboard controllers), the way memory is addressed and refreshed, the way memory is
tested, the wait states for memory, CPU and bus connections, the way ISA bus connections address
devices, and other such features. In order to make changes in this portion of the setup program,
documentation for the motherboard or advice from and experienced technician is required before making
substantial changes.
Power Management Options
The Power Management options let you enable or disable the power-saving (or Green) features of the
motherboard. Such motherboards can issue commands to specific devices (i.e., the hard disk, the
monitor) to power-down (or go to sleep) after a set number of minutes of inactivity. Many of these features
are set by device or by IRQ level. If your system stops operating properly after 10 - 20 minutes, you may
be encountering a situation where power management features are powering down your system.
PNP/PCI Setup Issues
The PNP/PCI Setup portion of the program allows you to control the configuration of the PCI bus
connections on the motherboard, and the way Plug-and-Play devices are polled and configured. You can
also tell the system board that a PNP-capable operating system (like Windows XP and above) is
installed, the speed and method by which PCI devices are to be addressed, enabling PCI VGA Palette
snoop (allowing a multimedia device to check the video card to see what color palette is being used),
whether data from PCI devices will move in streams or blocks, how the built-in drive interfaces will pass
data along the PCI bus, and also system monitoring features such as fan speed, CPU temperature, and
voltages on the motherboard. Using the Automatic option is the best choice for most systems.
Integrated Peripherals
This portion of the setup program allows you to enable, disable and/or configure the built-in peripheral
devices on your motherboard, such as the floppy drive controller, IDE interfaces, serial/parallel and PS/2
ports, and any other built in devices such as sound cards, video cards, SATA or SCSI host adapters, and
so forth. Devices can be both enabled and configured to operate at a specific configuration (i.e., the first
serial port can be configured to work as COM1:, COM3: or disabled; the parallel port can be set to work in
standard parallel port (SPP), enhanced parallel port (EPP), or enhanced communications port (ECP)
mode.). Make sure that these system board devices are configured properly, or else the devices may
conflict with other devices installed in the bus connections on the board.
Auto Detection Features
This portion of the setup program allows you to automatically detect the installed hard drives in your
system. The Cylinder/Head/Sectors-per-track (CHS) parameters from the detected hard drives are
passed to the Standard CMOS Setup part of the program, and if logical block addressing (LBA) mode or
some other form of sector translation is needed to access the drive as a single partition, those options will
be made available to the user at detection time. If the drive cables are not attached correctly, or if the
master/slave jumpers are set incorrectly, or if the drive is defective, the drive will not be detected.
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Custom configurations
The CMOS Setup program will normally come with an option to load the factory default settings for the
entire program, an option to load the values used for the previous boot, perhaps an option for "optimal
performance", and also perhaps an option for "fail-safe operation". Beyond that, you are able to tweak
any of these settings on your own beyond what the manufacturer provides for you with these canned
configurations.
UEFI BIOS Considerations
UEFI is, in many ways, like a miniature operating system. Because of that, hackers are developing
malicious software that can corrupt the BIOS. This can create serious problems that can render a PC
useless. Keeping your UEFI BIOS up-to-date with the latest version from the manufacturer will protect
you from potential problems. This is done by visiting the motherboard manufacturer’s website,
searching to determine if an update is available, downloading it if it exists, and following the directions
to flash and update the BIOS product.
When updating a BIOS product (standard OR UEFI), be sure to disable your antivirus application. An
antivirus application will view a BIOS upgrade as a potentially malicious activity, and will try to stop it
from taking place. That could leave you with a PC that is permanently out-of-service. SO long as you
observe the instructions from the manufacturer, the process should not damage your computer.
BIOS Companion textbook
A note from the author: There is a book that is worth its weight in GOLD as it relates to BIOS features.
It's called The BIOS Companion, and it's written by Phil Croucher. His book can be obtained over the
Internet at www.electrocution.com .
I strongly recommend your obtaining this book as a permanent desk reference about BIOS and CMOS
Setup issues. The ISBN number for this book is provided at the end of this course book.
NOTES
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William A. Lloyd
Chapter 4. Procedures for Testing Equipment
Repairing a faulty PC can be a challenge, but there are ways to systematically test and check a PC to
determine the nature of the problem and apply the proper solution. Begin by using these following ten
rules when repairing or trouble-shooting a computer:
1)
Gather together your toolkit, resource disks, and any necessary documentation for that
specific computer. You may also want to have these course notes available and/or any other
good resources for technical specifications and system disassembly guidelines.
2)
Check for power FIRST, before doing anything else. 10 - 15 percent of all trouble calls are for
nothing more than a popped circuit breaker or a loose power plug. Check these things BEFORE
doing anything else.
3)
Check your external connections to the computer. Specifically, check the mouse, keyboard,
monitor, modem and/or printer cables, making sure that all are secure and installed in the right
sockets.
4)
If the computer is still malfunctioning, go ahead then and open the case. Check to see that
all of the cards are fully pressed down into the bus connections, that any socketed chips are fully
pressed into their sockets, and that all cable connections are fully attached. Make sure that the
drive cables are attached so that the colored stripe on the cable is positioned next to pin 1 on the
connector.
5)
Clean any dust or foreign material out of the case while it is open. Dust can cause
overheating problems and electrical shorts. This is especially a problem with power supply
cooling fans and CPU heat sinks. All of this needs to be cleaned out before you close up the case.
Use compressed air and non-conductive materials to clean out the inside of the case. Take
precautions to avoid inhaling excess dust, and consider using protective eyewear if necessary.
6)
Try to boot the computer to the hard drive, or to a bootable CD/DVD disk if necessary.
Sometimes the hard disk will become corrupted by a user, or by a virus. If you can't access the
hard drive directly, have a bootable CD or DVD disk available (like your operating system
installation disk). Have a good disk diagnostic program available, and a good virus checking
program as well. If your data is severely damaged, you may need to wipe the disk and reload the
data from original or system recovery CD/DVD disks.
Also, if your PC will boot to a USB drive (such as a flash drive or external hard drive), see if the
system will respond and boot from these devices.
The course diagnostic DVD is an excellent tool for testing the hard drive and other key systems
inside your PC or laptop.
7)
Check the CMOS setup program, and correct any configuration problems. If the information
in CMOS RAM about your PC's configuration has been changed, or if the battery has died, your
computer will not boot correctly, or it will not recognize certain components. Keep a copy of your
setup program information handy, so that if something changes, you can correct the problem.
Replacement CMOS batteries are usually less than $10.00, and are readily available from
computer and electrical stores. Such batteries should last about 2-5 years.
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8)
Look for unwelcome changes. Someone may have turned the brightness down on a monitor, or
the LAN staff may have changed your PC's configuration without your knowledge (or approval), or
an installation program may have corrupted something in your software. Look for recent changes
in your system's operation. You may need to run an uninstaller application to remedy these
software-related problems.
9)
Isolate the problem to one piece of hardware, or one software package. The problem you
are encountering may occur only in one software package, which means the problem has a very
limited scope. If the problem occurs in all programs, then it's a systemic problem. Refer to
software and operating system manuals as needed, and have the original software disks
available, in case a driver needs to be reloaded. If the system just will not fire up, remove all
non-essential components, and see if you can cause the problem to re-appear by re-installing
components one-at-a-time. This process is usually quite helpful in trouble-shooting even the most
stubborn problems.
10)
When all else fails, read the manual. There may be something unique about your computer that
requires special attention as directed by the manufacturer.
Listed on the next few pages are step-by-step instructions for testing and troubleshooting the major
components within a PC; specifically:









Hard drives
Optical drives
Floppy drives [obsolete]
Monitors
Fax/modems [obsolete]
Keyboards and mice
Network interface cards (NICs)
Sound cards
Memory (DIMMs and SIMMs)
When testing various kinds of devices, it is a good idea to have some “known-good” parts available. For
example: if the optical drive you are testing appears to be defective, temporarily replace it with an optical
drive you know to be in good working order. This will enable you to rule out other problems, such as a bad
data cable, a bad drive interface, and so on.
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HARD DRIVE TESTING GUIDELINES
1)
Locate the hard drive in the system; notice the appearance of the hard drive.
There are several kinds of hard drives: IDE/EIDE, SCSI and SATA hard drives. In current
technology PCs, you will likely see IDE and Enhanced IDE drives (with 40-pin data cable
connectors) or SATA hard drives (with a small cable that connects each drive directly to the system
board interface).
Systems with SCSI drives have a 50-pin or 68-pin interface cable which attaches to the hard drive
and SCSI host adapter (drive interface) card.
Notice the model number and manufacturer of the drive; use that information to identify the
correct cylinder/head/sector per track specifications for that hard drive. Refer to the web site for
that drive manufacturer to find the proper information on that drive. This information will be
indicated on the label on newer hard drives.
The auto-detection feature in the CMOS setup program will retrieve the drive's technical
specifications directly from the diagnostic cylinder of the drive, thus relieving you from having to
manually input this information into the Setup program.
Also, make sure that the master/slave jumpers are set correctly on the IDE-style drive (or the
SCSI ID jumpers and terminating resistor are set for SCSI drives). For IDE-style drives, the
jumpers can be set for single, master or slave operation. If the drive is the only device on that
cable, make sure the drive is set either for single-drive or master-drive operation.
You can use the “cable-select” jumper position for both drives. When set for cable select, the drive
connected at the END of the cable is the master drive, and its controller will override the controller
on the drive connected to the middle cable connector.
Visit the web site for specific drive manufacturers to find the proper jumper setting information on
that particular drive, if that information is not obvious or available on the drive label. This is
especially true when setting the ID jumpers for a SCSI hard drive.
SATA hard drives do not need master/slave jumpers. They connect directly to the motherboard or
to the SATA interface adapter.
2)
Plug the hard drive into the drive cable and power supply cable within the PC (if not already
installed), and turn on both the monitor and PC. NOTE: if you plug the data cable onto the drive
BACKWARDS, the drive will likely not spin up. Most IDE data cables are keyed, so that you
cannot plug them in backwards. All power connections are keyed, so you can plug them in only
one way. If the drive is not recognized, double-check all cable connections.
The drive should whir and spin up when power and data cables are attached properly. If the drive
does not spin up, remove the drive the system, VIGOROUSLY shake the drive for 10-15 seconds,
and reinstall the drive into the system. If the drive does not spin up after this process, the drive is
defective and needs to be replaced.
If the drive makes loud ticking noises in a repetitive manner, this usually indicates that the drive’s
head positioner is damaged. If that is the case, the drive must be replaced.
3)
Run the ROM BIOS setup program and set the correct drive type. Use the "Hard Drive
Auto-Detection" routine in the Setup program to input the drive specifications into CMOS RAM;
many BIOS products detect the hard drives and optical drives automatically.
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4)
Boot the computer, and try to access the drive. If the computer gives you the error message that
says "Invalid drive specification", the drive likely is working, but the operating system is either
damaged or deleted. The same is true if you continually get “blue-screen-of-death” error messages.
You will need to partition and format the drive, typically with a Windows installation CD or DVD.
DO NOT attempt to perform a low-level format of the drive (using Disk Manager, MicroScope
2000 or some other program) unless you are given SPECIFIC instruction to do so from the
manufacturer's technical support staff. The low-level format was applied to the drive at the factory,
and it makes the drive readable by any operating system.
Specific software, made by that drive manufacturer, can safely perform such a format; generic
programs tend to damage or ruin the drive’s formatting characteristics. A low-level format will
PERMANENTLY remove the data from a hard disk, and there is no utility software that will let you
recover data from a drive that has been reformatted in this manner.
Make sure that you have the proper software to do the job properly; manufacturers have
specific programs they distribute that will safely low-level format a drive from that manufacturer.
Redoing the low-level-formatting on a drive should be the last possible resort when installing a
used hard drive into a system. Refer to Chapter 3 of this text for more information on how to
prepare a hard disk for use.
5)
Use some kind of diagnostic software to test the hard drive's operation (the course diagnostic
disk, Disk Manager, Microscope 2000, etc.). In fact, loading an operating system is a great test for
a hard drive. If the drive will not accept an operating system installation, the drive may have
serious problems. In addition, make sure the SMART (Self-Monitoring And Reporting
Technology) feature for hard drives is enabled in the system BIOS; it will report on screen if a
hard drive is showing signs of failure.
6)
If the hard drive does not work correctly, double-check and make sure that the hard drive is
correctly attached to the PC, and that the setup program has the correct specifications for that
particular drive. If the drive is making LOTS of noise, or if the drive becomes VERY HOT after a
short period of operation, or if the drive refuses to spin up, then the drive is probably defective.
7)
A last-ditch process can confirm if a hard drive truly is defective and beyond repair. On the bottom
of the hard drive, the disk controller board is attached by several small Torx-style screws.
Sometimes the hard drive or the controller board fails because the contacts on the hard drive
assembly do not make a proper connection to the controller. Over time, air causes oxidation to the
occur on the contact points on the controller board. When that happens, the hard drive may
malfunction or exhibit problems reading or writing data.
Remove the Torx screws that hold this board to the drive, then carefully detach the board from the
drive. Use a soft pencil eraser (not recommended by CompTIA) or some contact cleaner spray
(which is approved by CompTIA) to remove any oxidation on the contact points between the
board and the drive assembly. The contacts, when clean, should be silver or gold in color.
Reattach the board to the drive, and then repeat the above testing process starting at step one. In
some cases, the drive will begin to function again. If not, the drive truly is defective.
8)
If you are unsure of whether a hard drive is OK or not, contact the drive manufacturer's technical
support staff and support website location for further assistance.
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William A. Lloyd
OPTICAL DRIVE TESTING GUIDELINES
1)
Locate the optical drive in the system; notice the appearance of the drive. It should be attached to
an IDE/EIDE data cable or SATA data cable that connects to the system board. If the data cables
appear loose or the drive is not being recognized, detach and then reattach the data cables.
Check for pin 1 on an IDE/EIDE drive's data cable connector and pin 1 on the optical drive
controller connection on the system board, and make the necessary corrections (if the data cable
is NOT keyed). Also make sure the power cable is attached firmly to the drive.
2)
Run the ROM BIOS setup program and see if the drive is recognized by the system. In some
cases the setup program needs to be set to the “Auto” or “On” setting for the drive to be
recognized properly. If the drive is not recognized, and the data and power cables are connected
properly, the drive likely is defective and should be replaced.
3)
If the optical drive's tray does not open when the button is pushed, you can open the drive by
inserting a paperclip into the small hole below the disk tray. A disk may have become stuck in the
drive, or the tray may simply be stuck from environmental factors (sticky fluids, dust, etc.). If the
disk tray only opens up by using a paperclip, the drive is defective and should be replaced.
4)
Boot the computer using a known good optical disk; a Windows installation disk or the course
diagnostic DVD will work. If the drive will not read the disk or boot the computer with a
known-good bootable CD or DVD, the drive likely is defective and should be replaced.
Replace the drive with a known-good or new drive; if error messages continue to appear, or if the
PC will not boot to the optical drive, then the drive controller on the system board is defective.
Use some kind of diagnostic software to test the optical drive's operation, such as the course
diagnostic DVD or Microscope 2000. In fact, booting the PC with a bootable floppy disk is a great
test for a floppy drive. If the drive will not boot with a good operating system diskette or boot disk,
the drive has serious problems.
5)
Restart the computer, and let the Windows operating system load normally. If Windows cannot
read or write to the optical drive AFTER you tested the drive through step 4 above, then there
likely is a problem within the Windows Registry that is disabling the drive. You may also see in the
Windows Device Manager that the driver for the optical drive is “missing or corrupted.” Actually
the driver is fine, but the Registry contains some spurious information that is preventing the drive
from being accessed.
Use the online Microsoft Automated Troubleshooting Service (MATS) wizard to correct this
problem, or you can manually edit the Registry key for the optical drive to correct the problem.
Below is a link to the MATS CD/DVD/Blu-ray repair wizard.
http://support.microsoft.com/kb/314060
If this MATS repair wizard does NOT correct the problem, the Windows operating system will
need to be repaired or reinstalled to remedy this situation.
6)
Be sure that the front face of the drive is clean, and that the unit is free from dust. Use a can of
compressed air to clear out any dust or particulate matter.
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FLOPPY DRIVE TESTING GUIDELINES [obsolete]
1)
Locate the floppy drive in the system; notice the appearance of the drive. It should have a 34-pin
data cable and a 4-pin power cable attached to it; if this is not the case, properly attach the cables.
The part of cable with the "twist" on it (a method that differentiates the A: and B: drives) should be
attached to the A: drive, and if there is a second floppy drive, the other (middle) data connector
should be attached to that drive.
2)
Run the ROM BIOS setup program and set the correct drive type. Make sure that the "Floppy
drive A Type" is set to 1.44 MB. If there is a second floppy drive in the system, indicate that as well
in the setup program.
3)
If the floppy drive's disk access light stays solid-on all the time and never goes off, this indicates
that the floppy drive data cable has been installed backwards. Check for pin 1 on the drive's data
cable connector and pin 1 on the floppy drive controller connection on the system board, and
make the necessary corrections.
4)
Boot the computer, and try to access the drive. If the computer gives you the error message that
says "General failure reading drive A:" when reading a known good disk, replace the data cable.
If the drive continues to fail with a known-good data cable installed, then either the floppy drive or
the drive controller on the system board is defective.
Replace the drive with a known-good or new drive; if error messages continue to appear, or if the
PC will not boot to the floppy drive, then the drive controller on the system board is defective.
Use some kind of diagnostic software to test the floppy drive's operation, such as Checkit or
Microscope. In fact, booting the PC with a bootable floppy disk is a great test for a floppy drive. If
the drive will not boot with a good operating system diskette or boot disk, the drive has serious
problems.
5)
If you are unsure of whether a floppy drive is OK or not, contact the drive manufacturer's technical
support staff and support website location for further assistance.
NOTE: Floppy drives are obsolete on current-technology computers. However, some users
continue to retain important data on floppy disks. Encourage the customer to migrate this data to some
other data storage media, like a USB flash drive or a writable CD or DVD.
Many retail stores no longer sell floppy disks or floppy drives, and most PC manufacturers will not install
a floppy drive in a new PC.
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William A. Lloyd
MONITOR / VIDEO CARD TESTING GUIDELINES
1)
Notice the appearance of the monitor. If the cable has a 9-pin connector, it's either
Monochrome, CGA, or EGA. These are old, obsolete monitor types.
If there is a label on the monitor with 3-colors on it and it has a 9-pin cable connector, then it's
probably a CGA or EGA monitor. These are old, obsolete monitor types.
If the monitor has the word "Enhanced" on it and it has a 9-pin cable connector, it's probably an
EGA monitor. This also is an old, obsolete monitor type.
If you encounter one of these old, obsolete monitor types, take the monitor to a recycling
center, so that it can be disposed of in an environmentally-responsible manner. These types of
display monitors are no longer supported by current operating system or application developers.
2)
If the monitor cable has a 15-pin connector, it is a VGA/SVGA (or better) monitor.
If the monitor cable has a wider connector with more than 15 pins, it is an SVGA monitor with a
DVI (Digital Visual Interface) connector. Newer video cards also may have DisplayPort or HDMi
on them as well.
3)
Plug the monitor into the PC's video card connector; turn on the monitor first, and then the PC.
Also make sure that the monitor’s power connection is installed correctly.
NOTE: the cable connectors are keyed so that they fit onto the video card ONE WAY. DO NOT
force the cable onto the video card. Notice how the cable is keyed, and insert it onto the video
card connector gently. If you force the cable on backwards, you may damage the gold pins on the
connectors beyond your ability to repair them.
4)
If you hear a series of beep codes (i.e., one long and two short beeps) upon powering up the PC
and nothing appears on the screen, then the video card is probably defective or not operating
properly. Open the case of the system, then remove and replace the video card to re-seat it firmly
into the bus connection. If the beep codes persist, then the video card is most likely defective.
Replace the video card with a new or known-good card, connect the monitor cable to the card,
and continue the testing process.
5)
Use some kind of diagnostic software to test the monitor's display capability (the course
diagnostic DVD, MicroScope 2000, etc.). Note any messages that the diagnostic software gives
you during the testing of your monitor and video card.
6)
If the monitor does not display correctly, double-check and make sure that the monitor is attached
correctly to the video card. If there is "burn-in" on the screen (ghost images of letters or other
images visible on the CRT screen when it is turned off), or if the monitor does not display colors
properly, or if the screen appears fuzzy, then the monitor is defective.
Other monitor problems can include “dead pixels” (random black dots on the screen), dim
image (backlight is defective), flickering or distorted images (monitor controller board is
defective), or the screen is becoming unusually hot.
7)
For both CRT and flat-panel LCD monitors, make sure that the power plug is firmly and
completely connected to the monitor. If the LCD monitor has an AC adapter, use a volt-ohm
bench meter to ensure the adapter is working properly.
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William A. Lloyd
8)
If the LCD screen (or the CRT screen) is cracked or physically damaged, do not attempt to power
up the monitor. Take it to a recycling center, so that it can be disposed of in an
environmentally-responsible manner.
9)
If you are unsure of whether the monitor (or video card) is OK or not, contact the monitor (or video
card) manufacturer's technical support staff and support website location for further assistance.
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William A. Lloyd
KEYBOARD / MOUSE TESTING GUIDELINES
1)
Locate a keyboard; notice the appearance of the keyboard. There are 2 current kinds of
keyboards: PS/2 and USB keyboards. Even wireless keyboards will connect to either a PS/2 or
USB connection interface on the PC.
Keyboards with 5-pin DIN connector (these are larger than PS/2 connectors) are old and
essentially obsolete. If your PC uses an older 5-pin DIN keyboard, replacing such a
keyboard may be difficult. Adapters are available to convert PS/2-style keyboards to a 5-pin
DIN interface for use in older computers.
2)
Plug the keyboard into the PC, and then turn on both the monitor and PC. Make sure that your
PS/2-style keyboard is plugged into the keyboard connection on the system board, and not the
mouse connection. PS/2 keyboards and mice must be installed BEFORE powering the system;
otherwise, they will not be recognized.
The same rule applies with PS/2 mice: they must be plugged into the mouse plug, even though
the connection will fit into the keyboard plug. Many keyboards (and mice) have color-coded
connectors, or pictures to show you which device plugs into which connector.
DO NOT FORCE THE CONNECTORS into the sockets, and do not try to twist them in or out of
the connections on the system board. Breaking the keyboard connector on the system board will
require replacing the system board entirely; there is no simple fix for this problem.
For USB keyboards, use any available USB port on the PC (front or back) to connect the
keyboard.
3)
Use some kind of software to test the keyboard's operation (the course diagnostic DVD,
MicroScope 2000, etc.) You can also launch a word processing application, and simply press all
of the keys, one at a time, to test the keyboard.
4)
If the keyboard does not work correctly (i.e., one or more of the keys do not operate),
double-check and make sure that the keyboard is attached properly to the PC. Also, make sure
that the keyboard is free from anything that might interfere with the operation of any keys (i.e.,
food crumbs, paper shreds, dust, etc.); use compressed air to clean out the keyboard.
5)
If the keyboard is REALLY defective, simply replace the keyboard. It is more cost-effective to
replace the keyboard than to attempt to repair the unit.
6)
Testing procedures are similar for mice. Install the mouse in the PS/2 or USB connector at the
back of the computer, and then power up the PC. For USB mice, it may take a moment for the
driver to load before the mouse is recognized. If the mouse moves erratically, the ball and rollers
inside the mouse need to be cleaned, or the optical sensor needs to be cleaned.
If one of the buttons on the mouse does not respond, or if after cleaning the mouse it does not
work properly, simply replace the mouse with a new or known-good one. It is more cost-effective
to replace the mouse than to attempt to repair the unit.
7)
If you are unsure of whether a keyboard (or mouse) is OK or not, contact the manufacturer's
technical support staff and support website location for assistance.
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William A. Lloyd
FAX/MODEM TESTING GUIDELINES
1)
Locate the fax/modem inside your PC; it is the device that has two RJ-11 telephone jacks on it.
Make sure the card is firmly installed into the bus connector.
2)
Boot the PC into Windows. Right-click on My Computer, and then select the Properties option;
this will display the System Properties icon. Click on the Hardware tab, and then click on the
button for Device Manager. Your modem should appear in the Device Manager dialog box. If it
does not appear, or if it is listed as an “Other Device,” you will need to run the driver installation
program to properly install the fax/modem.
If the fax/modem does appear in the dialog box, double-click on it in the Device Manager. Click on
the Diagnostics tab, and then click on the Query Modem button. A screen of information gathered
from the fax/modem should appear. If you receive the error message "The modem failed to
respond", then the fax/modem is not operating properly.
3)
If you are attempting to reinstall the fax/modem, make sure that the fax/modem is not listed in the
Windows Device Manager under the "Other Devices" heading. If it is listed there, then the
fax/modem has not been properly installed; delete it from the Other Devices heading by clicking
once on the modem listing, and then clicking the "Remove" button. The fax/modem must be listed
under the "Modems" heading in the Device Manager. If the fax/modem is not listed under the
Modems heading, run the driver installation program to properly install the fax/modem.
4)
Be sure to use the proper driver for the fax/modem; this driver is typically provided by the
manufacturer when purchasing the fax/modem. It is possible that Windows may have a
compatible driver for the fax/modem, but it is best to use the driver provided by the manufacturer.
The driver installation wizard will prompt you as you install the software driver for the fax/modem.
If you do not have the driver, contact the fax/modem's manufacturer to obtain the driver (usually
from their web site).
5)
Make sure that the telephone cord is properly attached to both the fax/modem and to the wall jack;
otherwise, the fax/modem will not be able to make the connection to the telephone line and the
Internet. If the telephone cable is questionable, replace it with a known-good telephone cable. If
the cable is connected from the wall jack to the “Phone” plug on the modem, switch the cable to the
other connector.
6)
If the fax/modem works but cannot make the connection to the Internet or to your Internet service
provider (ISP), then a problem may exist with your Dial-up Networking configuration. Contact your
ISP's technical support staff for assistance. You may need to recreate or reconfigure your dial-up
networking icon's settings, or reinstall TCP/IP on your PC.
NOTE: dial-up networking to the Internet is nearly obsolete, and essentially unworkable
for most computer users. Recommend strongly to the customer that they should explore finding
broadband options for Internet connectivity (such as DSL, FiOS, cable broadband, or cellular
mobile broadband connections).
7)
If you are unsure of whether the fax/modem is OK or not, contact the fax/modem manufacturer's
technical support staff and support website location for further assistance.
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William A. Lloyd
SOUND CARD TESTING GUIDELINES
1)
Locate the sound card inside your PC; it is the device that has audio jacks and a game port
connector on it. Make sure the card is firmly installed into the bus connector. In some cases, the
sound card is built into the system board.
Also, make sure that the speaker connection is plugged into the speaker jack, and not into some
other jack. Further, make sure that the internal audio cable is connected from the CD-ROM drive
to the connection to the sound card (or system board). Also make sure that the speakers are
connected to power, turned on, and the volume level is turned up.
2)
Boot the PC into Windows. Right-click on My Computer, and then select the Properties option;
this will display the System Properties icon. Click on the Hardware tab, and then click on the
button for Device Manager. Your sound card should appear in the Device Manager dialog box. If it
does not appear, or if it is listed as an “Other Device,” you will need to run the driver installation
program to properly install the sound card.
3)
If you are attempting to re-install the sound card, make sure that the sound card is not listed in the
Windows Device Manager under the "Other Devices" heading. If it is listed there, then the sound
card has not been properly installed; delete it from the Other Devices heading by clicking once on
the device listing, and then clicking the "Remove" button.
The sound card must be listed under the "Sound, video and game controllers" heading in the
Device Manager. If the sound card is not listed under the "Sound, video and game controllers"
heading, run the driver installation program to properly install the sound card.
4)
Be sure to use the proper driver for the sound card; this driver is typically provided by the
manufacturer when purchasing the sound card. It is possible that Windows may have a
compatible driver for the sound card, but it is best to use the driver provided by the manufacturer.
The driver installation wizard will prompt you to install the software driver for the sound card. If you
do not have the driver, contact the sound card's manufacturer to obtain the driver (usually from
their web site).
5)
Make sure that the speakers are connected to the speaker jack, that the speakers are plugged
into power (if powered), and that the volume is turned up to an appropriate level. Also, make sure
that the volume control application in Windows has not been turned down or set to "Mute". The
Windows volume control is accessed by right-clicking on the speaker icon in the system tray (next
to the clock), or from the Windows Start menu.
Attempt to play an audio CD (just drop an audio CD into the optical drive), or play a sound from the
Sounds icon under the Control Panel to test the sound card and speakers. If you hear no
sounds, and you are certain that the device has been installed properly, then the sound card is
defective.
6)
If you are unsure of whether the sound card is OK or not, contact the sound card manufacturer's
technical support staff and support website location for further assistance.
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A Coursebook in PC Hardware, Maintenance & Repair
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Copyright, 2016
William A. Lloyd
NETWORK INTERFACE CARD (NIC) TESTING GUIDELINES
1)
Locate the NIC inside your PC; it is the device that has one RJ-45 twisted pair jack on it (and/or a
BNC coaxial cable connector on some older cards). Make sure the card is firmly installed into the
bus connector. Some system boards will have the NIC built into them.
DO NOT FORCE THE CONNECTORS into the socket, and do not try to twist them in or out of the
connections on the system board. Breaking the NIC connector on the system board may require
replacing the system board entirely to correct this problem.
2)
Boot the PC into Windows. Right-click on My Computer, and then select the Properties option;
this will display the System Properties icon. Click on the Hardware tab, and then click on the
button for Device Manager. Your NIC should appear in the Device Manager dialog box. If the
device does not appear, or if it is listed as an “Other Device,” you will need to run the driver
installation program to properly install the NIC.
3)
If you are attempting to re-install the NIC, make sure that the NIC is not listed in the Windows
Device Manager under the "Other Devices" heading. If it is listed there, then the NIC has not been
properly installed; delete it from the Other Devices heading by clicking once on the modem listing,
and then clicking the "Remove" button. The NIC must be listed under the "Network adapters"
heading in the Device Manager. If the NIC is not listed under the Network adapters heading, run
the driver installation program to properly install the NIC.
4)
Be sure to use the proper driver for the NIC; this driver is typically provided by the manufacturer
when purchasing the NIC. It is possible that Windows may have a compatible driver for the NIC,
but it is best to use the driver provided by the manufacturer. The driver installation wizard will
prompt you to install the software driver for the NIC. If you do not have the driver, contact the
NIC's manufacturer to obtain the driver (usually from their web site).
5)
Make sure that the network cable is properly attached to both the NIC and to the wall jack, router,
or hub; otherwise, the NIC will not be able to make the connection to the network and/or to the
Internet. If the network cable is questionable, replace it with a known-good cable.
6)
Some NICs come with a diagnostic program provided by the manufacturer. You should run this
diagnostic (if available) to ensure that the NIC is working properly.
7)
Most NICs have “link lights” that show if your cable is properly connected to the hub or router.
Other lights on the NIC may indicate the data transmission speed of your NIC. If these lights do
not illuminate, check the cable connections again, and ensure that the correct software driver for
the NIC is properly loaded.
It is possible for the cable connector in the NIC to be damaged, which results in a lack of a proper
connection. If this is the case, replace the NIC with another known-good unit.
8)
If the NIC appears to be working but cannot make the connection to the network, then a problem
exists with your Networking client software configuration. Contact your technical support staff for
assistance. You may need to reinstall or reconfigure your network client software, or check your
TCP/IP settings, or scan your PC for malicious software that is compromising your PC’s ability to
access the network or Internet.
9)
If you are unsure of whether the NIC is OK or not, contact the NIC manufacturer's technical
support staff and support website location for further assistance.
Preparing
for A+ Certification: 2016 Edition
A Coursebook in PC Hardware, Maintenance & Repair
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Copyright, 2016
William A. Lloyd
MEMORY TESTING GUIDELINES
1)
Insert the RAM to be tested into a known-good PC. Note that each system board requires specific
type of RAM; be sure to install the proper type of RAM, and make sure your do not install
mismatched types of RAM at the same time.
2)
Enter the CMOS Setup program. Make sure the Power-on Self-Test is NOT performing the “Quick
Boot” or similar option; this typically bypasses all of the major memory tests performed at POST.
Save the settings in the CMOS Setup program, and allow the PC to reboot.
3)
Let the PC boot to the Windows operating system. If the RAM is working properly, you should not
encounter any error messages.
If you see the “Blue Screen of Death” type of error message while booting, or if Windows fails
shortly after loading, defective or an incorrect type of RAM may likely be the cause.
4)
Boot the PC using a diagnostic software program (such as the course diagnostic DVD or
MicroScope 2000) to test the memory. Such programs can be run from a floppy disk, CD or USB
flash drive. Launch the diagnostic program, and run the memory testing portion of the program. It
should be able to detect any defects in the system RAM.
5)
If after running the memory diagnostic no memory errors are detected, run the memory test again
in batch mode. Repeated runs of a memory test over a 20 - 30 minute period will detect errors that
occur as the memory is stressed and as the temperature of the RAM increases over time.
6)
If memory errors are detected, replace the SIMMs or DIMMs with known-good memory. If no
memory errors are detected, run a complete virus scan on the hard drive; some operating system
errors brought on by viruses or malware can act like memory errors.
7)
If the replacement RAM does not correct the memory problem, ensure that the memory SIMMs or
DIMMs are securely seated in their sockets. If the problem persists, there may be a problem with
the system board and/or the memory sockets.
8)
If you are unsure of whether the memory and/or motherboard is OK or not, contact the memory
and/or the motherboard manufacturer's technical support staff and support website location for
further assistance.
Preparing
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A Coursebook in PC Hardware, Maintenance & Repair
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Copyright, 2016
William A. Lloyd
Chapter 5. Procedures for Installing Components
Part of your work as a PC repair technician involves the installation of new or replacement components.
It is important to know how to install devices, and how to do the work in the proper order. This next section
of the text gives step-by-step instructions on how to install the following types of major devices:
●
●
●
●
●
●
●
●
Hard drives
Optical drives (CD, DVD and Blu-ray)
Sound cards
Fax/modems
Video cards, TV tuner and video capture cards
Network interface cards
Thunderbolt, USB and FireWire cards
Replacement/additional memory
Whenever possible, have available on hand the driver disks and documentation for the device you will be
installing. When Windows detects a new device, it will prompt you to load the vendor-supplied device
driver, if a driver for the device is not already available to the system.
Knowing the brand and model of device you are installing, along with where the driver is located on the
installation disk, will speed the process of installing a new device correctly.
It is also valuable to know how to contact the hardware vendor and/or the manufacturer for information
and assistance when installing new devices into your computer. If you require assistance in installing a
device, the manufacturer or vendor should be able to quickly guide you through any problems.
The installation checksheets that follow are laid out in the following format:
●
●
●
●
Tools and parts needed
Software needed
Step-by-step instructions
Installation tips
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Copyright, 2016
William A. Lloyd
HARD DISK INSTALLATION CHECKSHEET
Tools and parts needed:
o
Flat/Phillips screwdrivers, and an ESD wrist-strap
o
Drive mounting screws, and perhaps drive mounting rails
o
Hard drive(s)
o
Correct drive cables (IDE, SCSI or SATA)
Software needed:
o
Windows installation CD or DVD, Linux installation CD, or other operating system install disk
o
Any desired application software
o
The course diagnostic DVD
Step-by-step instructions:
1)
Open the computer case;
2)
If installing an IDE drive, check and/or set the master/slave jumpers on both the old AND
new drives; the new (second) drive likely will be set to slave or cable-select, and the drive
currently installed will be set to master or cable-select;
For SCSI drives, set the SCSI ID jumpers to a unique SCSI ID number, and set termination on
or off (depending if it is the highest-numbered or last drive in the chain);
For SATA drives, attach the data cable from the back of the drive to the SATA interface on the
system board (no jumpers need to be set on SATA drives);
3)
Write down the storage capacity and drive parameters (cylinders, heads, sectors per track, etc.)
before mounting drive into PC (consult drive's documentation or company's website if needed);
4)
Physically mount the drive into case; use screws and/or drive rails as needed;
5)
Attach the cable to the drive(s); be sure to attach the power cable from the power supply;
6)
Power up the PC; enter the BIOS setup program and enter the drive parameters into CMOS.
Use the hard drive auto-detection feature to enter this information into the setup program for
you automatically. Note that SCSI drives should be set in the CMOS Setup program to Off or
Drive Type 0 - Not Installed; the SCSI host adapter will identify the drives.
7)
Before exiting the BIOS Setup program, make sure the PC is set to boot from the optical drive
FIRST; this is necessary to run the operating system installation CD (or DVD);
8)
Exit the Setup program; save the revised information to CMOS and reboot the PC;
9)
Boot the PC from the Windows (or Linux) installation CD or DVD;
10)
Follow the prompts to partition and format the drive, and then install the operating system;
11)
If you are installing a second hard drive in an existing Windows-based system, right-click upon
My Computer, and select the Manage option. In the Management Console, select the Disk
Management tool, then right-click on the new (unformatted) drive in the dialog box, and select the
Partition Drive option. Once the drive is partitioned, you then can right-click on the partition and
select the Format option. Use the “Quick Format” option for new drives.
Preparing
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Copyright, 2016
William A. Lloyd
12)
Install any required application software as needed;
13)
Replace the computer case - do NOT install the cover until you know the drive is working properly.
Installation tips:
1)
Hard drives larger than 528 MB need to use the LBA (logical block addressing) mode feature in
the system BIOS for the whole drive to be recognized. Logical Block Addressing mode “lies to
your BIOS about the architecture of your hard disk,” so that all available space can be used. ALL
PCs have some form of LBA mode built into the BIOS, and that feature will allow the entire
drive to be utilized, so long as the feature is enabled.
However, some older system BIOS products have an older version of the LBA mode feature that
only will recognize drives up to 2TB. If this is the case, and you are looking to install a drive larger
than 2TB, you will need to upgrade the BIOS version with software from the PC or system board
manufacturer, or use a smaller hard drive that the current BIOS product will accept.
2)
If the number of bad sectors on the drive exceeds 5 percent of the total disk space, replace the
drive: it is defective. Also, if you get repeated messages where the screen says "Trying to recover
allocation unit (some number)", there are problems with the physical surface of the hard drive, and
the drive should be replaced.
In addition, make sure the SMART (Self-Monitoring And Reporting Technology) feature for hard
drives is enabled in the system BIOS; it will report on screen if a hard drive is showing signs of
failure.
3)
Be sure to have the 800-number and support website location for the drive manufacturer available
for technical support if needed. If the drive is still under warranty, contact the manufacturer to
obtain a Return Merchandise Authorization (RMA) number, which is needed for the drive to be
replaced.
4)
Refer to Chapter 2 in this text for additional information on the steps required to prepare a hard
disk for use.
Preparing
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A Coursebook in PC Hardware, Maintenance & Repair
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Copyright, 2016
William A. Lloyd
SOUND CARD INSTALLATION CHECKSHEET
Tools and parts needed:
o
Flat/Phillips screwdrivers, and an ESD wrist-strap
o
Mounting screws
o
Sound card
o
Audio cable to attach CD/DVD-ROM drive to sound card
o
Speakers
Software needed:
o
Installation disk for the new sound card
o
An audio CD disk (for testing purposes)
o
The course diagnostic DVD
Step-by-step instructions:
1)
Open the computer case;
2)
Install the new sound card in any free white PCI bus connection;
3)
Attach the audio cable from the optical drive to the sound card;
4)
Attach the speakers to the speaker connection on the sound card. Make sure the speakers are
powered up, and that the volume control is turned up;
5)
Power up the PC; run the sound card installation/setup program from the installation CD, or when
prompted by the Windows Add New Hardware Wizard; when the install program is finished,
reboot the PC;
6)
Test the sound card by playing an audio CD, or play back any wave or MIDI files installed on the
PC (some samples can be found in the My Music folder). Windows also will generate sounds
when it boots up ... listen for these sounds;
7)
Replace the computer case - do NOT install the cover until you know the card is working properly.
Installation tips:
1)
Be sure to plug the speakers into the right connector on the back of the sound card; also, be sure
to check the volume of the speakers (either through the sound card software, or by adjusting the
volume control on the speaker or card);
2)
Be sure to have the 800-number and support website location for the drive manufacturer available
for technical support if needed.
3)
Many system boards have the sound cards built in. Ensure that the sound card is enabled in the
CMOS Setup program; otherwise, the sound card will not function properly.
4)
Make sure you have the PROPER driver for the device, and that the driver is compatible to the
operating system currently in use on the PC. Improper drivers will prevent the device from
operating correctly.
Preparing
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A Coursebook in PC Hardware, Maintenance & Repair
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Copyright, 2016
William A. Lloyd
OPTICAL DRIVE INSTALLATION CHECKSHEET
Tools and parts needed:
o
Flat/Phillips screwdrivers, and an ESD wrist-strap
o
Mounting screws, and perhaps drive mounting rails
CD/DVD-ROM, or Blu-ray drive
o
o
Correct drive cables (IDE, SATA or SCSI)
o
Audio cable to attach optical drive to sound card
Software needed:
o
An audio CD and a data CD/DVD-ROM disk (for testing purposes)
o
Installation CD for DVD playback and/or disk-mastering software
o
The course diagnostic DVD
Step-by-step instructions:
1)
Open the computer case;
2)
If installing an IDE-class optical drive, set the master/slave jumpers on both the old AND new
drives (typically you will set the jumper to slave on the optical drive);
For SCSI drives, set the SCSI ID jumpers to a unique ID number, and set termination on or off
(depending if it is the highest-numbered or last drive in the chain);
For SATA drives, attach the data cable from the back of the drive to the SATA interface on the
system board (no jumpers need to be set on SATA drives);
3)
Attach the optical drive to either the primary or secondary IDE interface cable, or install a cable
from the SATA CD/DVD drive to the SATA interface on the controller or system board; if the
optical drive is a SCSI type, attach the data cable to the SCSI host adapter;
4)
Attach the audio cable from the optical drive to the sound card; be sure to attach the power cable
from the power supply;
5)
Physically mount the drive into the case; use screws and/or drive rails as needed;
6)
Power up the PC; run the optical installation/setup program for the DVD playback or
disk-mastering software; when the install programs are finished, reboot the PC;
7)
Test the optical drive by installing a program or reading a file from a CD or DVD data disk, or play
an audio CD on the new drive, or play a movie DVD, or try to write a new data disk on the drive;
the course diagnostic DVD is an excellent choice for testing the new optical drive;
8)
Replace the computer case - do NOT install the cover until you know the drive is working properly.
Installation tips:
1)
Be sure to note where pin 1 is on the cable connector - plugging in the cable backwards may
cause the hard drive to shut down. Most cables are keyed to ensure proper installation, but some
are not. Also, be sure to set the master/slave jumper on the drive.
2)
Be sure to have the 800-number and support website location for the drive manufacturer available
for technical support if needed.
Preparing
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A Coursebook in PC Hardware, Maintenance & Repair
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Copyright, 2016
William A. Lloyd
FAX/MODEM INSTALLATION CHECKSHEET
Tools and parts needed:
o
Flat/Phillips screwdrivers, and an ESD wrist-strap
o
Mounting screws
o
Fax/modem
o
Telephone cable (to wall jack)
Software needed:
o
Installation driver disk for the new fax/modem
o
The course diagnostic DVD
Step-by-step instructions:
1)
Open the computer case;
2)
All modems are now Plug-and-Play compliant, so there will be no jumpers or switches to set; the
installation script that runs with the "Add New Hardware Wizard" will install the modem to the
correct parameters for you;
3)
Install the new fax/modem in any free white PCI bus connection;
4)
Attach the telephone cable from the wall jack to the jack marked "LINE", and attach your existing
telephone to the jack marked "PHONE";
5)
Power up the PC; the operating system should detect a new modem; insert the driver installation
disk into the optical drive. Run the driver installation program, and make sure the operating
system locates the correct driver for the fax/modem;
6)
Install any fax/modem software or on-line software you desire; then, test the fax/modem by
attempting to go on-line with the modem software you just installed;
7)
Replace the computer case - do NOT install the cover until you know the card is working properly.
Installation tips:
1)
Be sure to plug the telephone cable into the proper jack on the fax/modem, and into the wall jack
as well;
2)
Be sure to have the 800-numbers and support website location for the modem manufacturer
and/or on-line service available for technical support if needed;
3)
If you had a modem previously installed in the PC, delete the previous modem configuration
BEFORE you install the new modem; otherwise, the new modem may not be recognized
correctly.
4)
Use the modem diagnostic available in the Device Manager to test your new modem. On the icon
in the Device Manager for your modem, click on the Diagnostics tab, and then click on the "Query
Modem" button. If your modem is not working, a screen will appear telling you that the modem
failed to respond; otherwise, you will see a screen of information gathered from the ROM chip on
your modem indicating your modem is working.
Preparing
for A+ Certification: 2016 Edition
A Coursebook in PC Hardware, Maintenance & Repair
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Copyright, 2016
William A. Lloyd
VIDEO CARD INSTALLATION CHECKSHEET
Tools and parts needed:
o
Flat/Phillips screwdrivers, and an ESD wrist-strap
o
Mounting screws
o
Fax/modem
o
Video cable that connects to monitor
Software needed:
o
Installation driver disk for the new video card
o
The course diagnostic DVD
Step-by-step instructions:
1)
Before opening the computer case, notice if there is a video card (VGA 15-socket port) already
built into the motherboard. You can install a video card even if one is already built-in on the
system board. You will need to indicate in the CMOS Setup program that you are using a
third-party (user-installed) video card instead of the built-in one.
2)
Insert the new video card into either the AGP or the PCI-E (or PCI-X) slot on the motherboard;
note the tab at the end of the PCI-E or PCI-X slot that will allow you to remove the card if
necessary; fasten the card to the case with a retaining screw. If needed, attach a power supply
connection to the video card (only for high-end or gaming video cards);
3)
Connect the video cable (VGA, DVI or HDMi) from the monitor to the video card, and tighten the
thumbscrews to barely snug;
4)
Power up the PC; when the operating system detects the new video card, insert the driver
installation disk into the optical drive. Run the driver installation program, and make sure the
operating system locates the correct driver for the video card;
6)
Once the video card driver is installed, let the computer reboot. This will allow the new video card
to operate with the proper drivers. Check and adjust the video resolution to suit your needs;
7)
Replace the computer case - do NOT install the cover until you know the card is working properly.
Installation tips:
1)
Be sure to use the original equipment manufacturer (OEM) driver to obtain the best quality video.
The Microsoft-issued driver may not have all the functionality of the OEM driver;
2)
Be sure to have the 800-numbers and support website location for the video card manufacturer
available for technical support if needed;
3)
If the video card on the motherboard has malfunctioned and you are installing a video card to
correct the problem, make sure the onboard video card is DISABLED in the CMOS Setup
program. If the onboard video card is disabled and the PC does not recognize the new video card,
a motherboard replacement may be the only solution. The damaged onboard video card may be
preventing the new card from being recognized properly.
4)
TV tuner and video capture cards will install in the same manner as a video card, and similar
procedures can be followed.
Preparing
for A+ Certification: 2016 Edition
A Coursebook in PC Hardware, Maintenance & Repair
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Copyright, 2016
William A. Lloyd
NETWORK INTERFACE CARD INSTALLATION CHECKSHEET
Tools and parts needed:
o
Flat/Phillips screwdrivers, and an ESD wrist-strap
o
Mounting screws
o
Network interface card (NIC)
o
RJ-45 network cable (to attach to network wall jack or hub)
Software needed:
o
Driver installation disk for the new network interface card
o
Network client installation software, and/or your Windows installation CD
o
Diagnostic software (if included with your NIC)
o
The course diagnostic DVD
Step-by-step instructions:
1)
Open the computer case;
2)
All NICs are now Plug-and-Play compliant, so there will be no jumpers or switches to set; the
installation script that runs with the "Add New Hardware Wizard" will install the NIC to the correct
parameters for you;
3)
Install the new NIC in any free white PCI bus connection;
4)
Attach the network cable to the RJ-45 jack on the NIC, and make sure the other end is attached to
the hub, router or network wall jack;
5)
Power up the PC; the operating system should detect a new NIC; insert the driver installation disk
into the CD/DVD-ROM drive, and make sure the operating system locates the correct driver for
the NIC;
6)
Test the NIC by attempting to log onto the network or access the Internet. Also, you can run the
command IPCONFIG from the Command window to see if you have obtained an IP address for
your NIC;
7)
Replace the computer case - do NOT install the cover until you know the card is working properly.
Installation tips:
1)
Be sure to plug the network cable into the jack on the NIC, and into the hub, router or network wall
jack as well. Make sure the link lights are illuminated, indicating a proper connection to your router
or hub;
2)
Be sure to have the 800-numbers and support website location for the NIC manufacturer and/or
on-line service available for technical support if needed;
3)
If you had a NIC previously installed in Windows, delete the previous NIC configuration BEFORE
you install the new NIC; otherwise, the new device may not be recognized correctly.
4)
Run any diagnostics that came with the NIC, if available, to test the device. Simply getting onto
the Internet or logging into the network is a good test.
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William A. Lloyd
THUNDERBOLT, USB AND FIREWIRE CARD INSTALLATION CHECKSHEET
Tools and parts needed:
o
Flat/Phillips screwdrivers, and an ESD wrist-strap
o
Mounting screws
o
Thunderbolt card (or USB or FireWire card)
o
Thunderbolt cable (to attach to Thunderbolt-capable devices)
Software needed:
o
Driver installation disk for the new Thunderbolt (or USB or FireWire) card
o
The course diagnostic DVD
Step-by-step instructions:
1)
Open the computer case;
2)
Thunderbolt cards are Plug-and-Play compliant, so there will be no jumpers or switches to set;
the installation script that runs with the "Add New Hardware Wizard" will install the card to the
correct parameters for you;
3)
Install the Thunderbolt/USB/FireWire card in any free white PCI bus connection;
4)
Power up the PC; the operating system should detect the Thunderbolt (or USB or FireWire) card; insert
the driver installation disk into the CD/DVD-ROM drive, and make sure the operating system
locates the correct driver;
5)
Test the card by attempting to connect a Thunderbolt-capable device (or USB or FireWire
device) to the card, using the appropriate cable;
6)
Replace the computer case - do NOT install the cover until you know the card is working properly.
Installation tips:
1)
Be sure to have the 800-numbers and support website location for the NIC manufacturer and/or
on-line service available for technical support if needed;
2)
Run any diagnostics that came with the card, if available, to test the device. Simply connecting
the card to a Thunderbolt-capable device is a good way of testing the card.
3)
A USB or FireWire card can be installed using the same procedures as shown above for a
Thunderbolt card.
Preparing
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William A. Lloyd
MEMORY INSTALLATION CHECKSHEET
Tools and parts needed:
o
Flat/Phillips screwdrivers, and an ESD wrist-strap
o
Memory SIMM, SODIMM or DIMM units
Software needed:
o
Diagnostic software, such as the course diagnostic DVD or MicroScope 2000 (or a comparable
diagnostic)
Step-by-step instructions:
1)
Open the computer case;
2)
Locate the available slots for the new memory; if all of the slots are filled, you will need to replace
the existing memory with similar SIMMs or DIMMs of higher capacity;
3)
SIMMs and SODIMMs are notched so that they only insert into the socket one way; insert the
SIMM/SODIMM at an angle, making sure that the memory is fitting into the socket, and tilt the
SIMM/SODIMM until it locks into the socket in a upright position.
4)
DIMMs have two or three different-sized segments on the bottom of them, ensuring that they only
insert one way into the socket; place the DIMM directly into the socket, and press one corner
down into the socket, and then the other corner. When they insert properly, the two arms on the
DIMM socket will lock upright and keep the DIMM from coming out of the socket;
5)
Power up the PC; the Setup program and the operating system should detect a new memory;
enter the setup program for the PC, verify that it sees all of the new memory, save the new
configuration and exit the setup program.
6)
If the computer gives you an error message about "unreliable XMS memory", this indicates that
your memory is defective, mismatched with your existing memory, or not configured properly in
the BIOS. Reboot the PC, enter the Setup program, and look for any memory timing setup
features under the "Advanced Chipset Setup" portion of the Setup program, and make sure that
the values are proper for the type of memory installed in the PC.
Installation tips:
1)
Be sure to match the new memory up with the existing memory in the system; all of the memory
units should be of the same type and speed (but not necessarily from the same manufacturer). If
they are not, problems are likely to occur.
2)
Have the memory tested by the vendor BEFORE completing the sale; most memory vendors will
test the new memory for you at no charge before completing the sale.
3)
Be sure to have the 800-numbers and support website location for the modem manufacturer
and/or on-line service available for technical support if needed. Most memory comes with a
LIFETIME warranty;
4)
Booting and running Windows for 30 - 60 minutes is typically an adequate test of whether your
new memory is working properly. The course diagnostic DVD has a dedicated memory testing
program that you also can use to evaluate your installed RAM.
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for A+ Certification: 2016 Edition
A Coursebook in PC Hardware, Maintenance & Repair
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Copyright, 2016
William A. Lloyd
Chapter 6. Troubleshooting Guidelines
A major part of the A+ certification program revolves around the technician's ability to assess the
condition of a PC, identify the problem with the PC, and then apply the proper solution to the problem.
Sometimes the problem is located with the hardware, sometimes the problem is with the software,
sometimes it can be a combination of the two, and sometimes the problem is because of user error.
Your job is to determine, as quickly as possible, the nature of the problem and implement the proper
solution.
In this section of the text, we will cover material that will help you to become an adept PC problem
troubleshooter.
Diagnostic software
A good piece of diagnostic software can quickly identify a problem with a defective piece of hardware, or
at least let you determine that the problem is with something other than the hardware of the PC.
Diagnostic software is as important to the technician as a set of tools or an ESD strap. There are several
utilities that are worthy of consideration that can help you to accurately troubleshoot and diagnose
problems with a computer. They are described below.
Note that the author has no financial or fiduciary investments related to the recommended diagnostic
programs described in this chapter of the text.
Parted Magic Course Diagnostic DVD
To assist you in diagnosing and troubleshooting problems with PCs and laptops, we will provide you with
a bootable diagnostic DVD application developed and compiled by my son, Matthew Lloyd.
The Parted Magic application provides a number of applications that will help you to:








Test hard drives for proper operation
Create, delete or resize partitions on a hard disk
Transfer data safely from a failing or virus-infected hard drive to a USB flash drive or optical disk
media
Check the temperature sensors in a PC or laptop to determine overheating conditions
Test the memory in a PC or laptop for defects and problems
Change or remove a password on a Windows-based operating system
Clone a hard disk using the Clonezilla application
Get a summary of detected equipment in a PC or laptop
The applications on this disk are open-source, which means that they can be copied and shared freely
with others. The DVD uses Linux as its operating system, so it will work whether the computer’s operating
system is in working order or not. You will boot the computer to the optical (DVD) drive, rather than to the
hard disk, to launch and use this diagnostic program.
This suite of diagnostic tools is one of the best in the industry, and we are happy to provide it to you during
the course. We will make it available to you several weeks into the course, when you are trained
sufficiently to understand how to use it and view the results.
We ask that you make a $10.00 contribution towards the cost of providing you with this resource.
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A Coursebook in PC Hardware, Maintenance & Repair
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Copyright, 2016
William A. Lloyd
Windows Driver DVD Disk
We also will provide you with a DVD that contains literally thousands of device drivers on the disk. This
will assist you in the event you need to install a device driver or update a driver that is defective. The disk
has drivers for Windows XP, Windows Vista and Windows 7.
We also ask that you make a $10.00 contribution towards the cost of providing you with this resource.
MicroScope 2000
MicroScope 2000 is one of the better diagnostic programs available to the PC technician today. The
breadth of capabilities and its independence from any particular operating system makes it the diagnostic
software of choice for the serious PC technician. HOWEVER, it is an expensive piece of software; the
retail price of MicroScope 2000 is several hundred dollars. By comparison, the course diagnostic DVD
will provide you with virtually all of the features in MicroScope 2000, but at no cost.
To obtain further information about MicroScope 2000, visit their website at: http://www.micro2000.com .
Active Boot Disk
Active Boot Disk is a robust diagnostic suite that will let you perform file recovery from disks, partition
recovery on a failing hard drive, disk imaging utilities, and file transfers to USB flash drive or optical disks.
It recognizes operating systems from DOS through Windows 10. A free demo version is available for
download from their website, and the personal version of the application costs $79.99. Business and
enterprise licensing also is available for this product.
To obtain further information about Active Boot Disk, visit their website at:
http://www.lsoft.net/bootdisk.aspx .
Problem solving guidelines
Repairing a faulty PC can be a challenge, but there are ways to systematically test and check a PC to
determine the nature of the problem and apply the proper solution. Begin by using these following ten
rules when repairing or trouble-shooting a computer (this section is repeated from earlier in the text):
1)
Gather together your toolkit, resource disks and any necessary documentation for that
specific computer. You may also want to have these course notes available and/or any other
good resources for technical specifications and system disassembly guidelines.
2)
Check for power FIRST, before doing anything else. 10 - 15 percent of all trouble calls are for
nothing more than a popped circuit breaker or a loose plug. Check these things BEFORE doing
anything else.
3)
Check your external connections to the computer. Specifically, check the mouse, keyboard,
monitor, modem and/or printer cables, making sure that all are secure and installed in the right
sockets.
4)
If the computer is still malfunctioning, go ahead then and open the case. Check to see that
all of the cards are fully pressed down into the bus connections, that any socketed chips are fully
pressed into their sockets, and that all cable connections are fully attached. Make sure that the
drive cables are attached so that the colored stripe on the cable is positioned next to pin 1 on the
connector.
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Copyright, 2016
William A. Lloyd
5)
Clean any dust or foreign material out of the case while it is open. Dust can cause
overheating problems and electrical shorts. This is especially a problem with power supply
cooling fans and CPU heat sinks. All of this needs to be cleaned out before you close up the case.
Use compressed air and non-conductive materials to clean out the inside of the case. Take
precautions to avoid inhaling excess dust, and consider using protective eyewear if necessary.
6)
Try to boot the computer to the hard drive, or to a bootable CD/DVD disk if necessary.
Sometimes the hard disk will become corrupted by a user, or by a virus. If you can't access the
hard drive directly, have a bootable CD or DVD disk available (like your operating system
installation disk). Have a good disk diagnostic program available, and a good virus checking
program as well. If your data is severely damaged, you may need to wipe the disk and reload the
data from original or system recovery CD/DVD disks.
Also, if your PC will boot to a USB drive (such as a flash drive or external hard drive), see if the
system will respond and boot from these devices.
The course diagnostic DVD is an excellent tool for testing the hard drive and other key systems
inside your PC or laptop.
7)
Check the CMOS setup program, and correct any configuration problems. If the information
in CMOS RAM about your PC's configuration has been changed, or if the battery has died, your
computer will not boot correctly, or it will not recognize certain components. Keep a copy of your
setup program information handy, so that if something changes, you can correct the problem.
Replacement CMOS batteries are usually less than $10.00, and are readily available from
computer and electrical stores. Such batteries should last about 2-5 years.
8)
Look for unwelcome changes. Someone may have turned the brightness down on a monitor, or
the LAN staff may have changed your PC's configuration without your knowledge (or approval), or
an installation program may have corrupted something in your software. Look for recent changes
in your system's operation. You may need to run an uninstaller program to remedy
software-related problems.
9)
Isolate the problem to one piece of hardware, or one software package. The problem you
are encountering may occur only in one software package, which means the problem has a very
limited scope. If the problem occurs in all programs, then it is a systemic problem. Refer to
software and operating system manuals as needed, and have the original software disks
available, in case a driver needs to be reloaded. If the system just will not fire up, remove all
non-essential components, and see if you can cause the problem to re-appear by reinstalling
components one-at-a-time. This process is usually quite helpful in trouble-shooting even the most
stubborn problems.
10)
When all else fails, read the manual. There may be something unique about your computer that
requires special attention as directed by the manufacturer.
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A Coursebook in PC Hardware, Maintenance & Repair
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Copyright, 2016
William A. Lloyd
Proprietary systems vs. conservatively designed systems
Proprietary computers systems present a variety of challenges to the repair technician. Proprietary
systems require parts made specifically by a certain vendor for a specific type of computer they have
manufactured. For example, many Compaq computers require Compaq hard drives or Compaq memory
when upgrading a system or replacing a defective part. These types of problems are common with the
major computer manufacturers such as Hewlett-Packard, Compaq, Dell, Toshiba or IBM.
Further, many manufacturers have designed their computers so that most or all of the devices for that
system have been built into the system board. Such computers may have sound cards, video cards
and/or network interface cards built into the motherboard. This is fine until the system breaks ... the cost
of replacing such motherboards out-of-warranty usually exceeds the cost of the computer system itself.
Manufacturers like Dell and HP/Compaq routinely make such systems (as do the manufacturers
mentioned in the previous paragraphs). In order to obtain replacement parts in many cases, you must
become an authorized repair and parts facility for that manufacturer. This usually involves paying a fee of
several thousand dollars to the company, and then you must hold several thousand dollars in parts
inventory in addition to the fee. You may encounter a variety of problems when attempting to service
proprietary systems.
Many local computer "home-brewers" build conservatively-designed PCs. These companies build PCs
using name-brand parts that are designed to be put into standard PC cases, and will accept a wide range
of computer components such as video cards, sound cards, modems and network interface cards.
There is nothing proprietary in any of these systems ... they are intended to be competitive with
better-known name-brand PCs, many of which have similar components built into them. In fact, they offer
the computing customer tremendous options when looking to build a customized system that exactly fits
the user's needs.
Whenever possible, encourage a potential consumer that conservatively-designed systems offer
significant advantages over proprietary, name-brand systems.
System Board Problems
If you believe that the computer’s motherboard may have become defective, you may want to perform
some simple checks, such as:




Look for capacitors (little round cylinders) that may be swollen, distended, or damaged; this may
indicate a failure that came from overheating, ESD discharge, dust build-up, or cheap
components having been installed
Make sure the CPU is properly seated in the socket; even though it might not appear to have
moved, overheating or jostling the system can dislodge the chip. Remove the heatsink and fan,
remount the chip, and reinstall the heatsink/fan
If the heatsink/fan assembly has been caked over with dust, the CPU itself may have
overheated; try replacing the CPU with an identical chip, replace the heatsink/fan with a new
one, and test the system
Take notice of any strange smells or strong odors in the system; they may be indicators of
components that have overheated and failed; make sure system fans are running properly, and
listen for loud, unusual noises
NOTES
Preparing
for A+ Certification: 2016 Edition
A Coursebook in PC Hardware, Maintenance & Repair
Page 92
Copyright, 2016
William A. Lloyd
Chapter 7. Building a PC from Scratch
Many people nowadays prefer to build their own custom-designed PC, rather than buying a pre-built PC
made by a major company or local PC vendor. Building your own customized PC has a number of
advantages over purchasing pre-built name-brand computers. Custom PCs can be less expensive than
pre-built name-brand PCs.
However, depending upon the kinds of components you put into a custom PC, the cost can exceed a
name-brand PC being sold at a sale price. So why would you want to build your own PC?
Conservatively-designed PCs give you more customization options, and are cheaper to repair
than non-conservatively designed PCs.
A conservatively-designed PC does not have a lot of extra devices built into the motherboard, such as:
- Video card
- SCSI host adapters - Network cards - Sound cards
It is better, from a repair standpoint, to have these devices plugged into the bus connectors of the
motherboard as separate devices than to have them integrated into the motherboard. Why? These
individual devices are easy to replace and much less expensive than replacing an entire motherboard for
the failure of a single part on that motherboard.
Admittedly most motherboards have many of these devices built into them nowadays. However, the
argument for having separate cards for different system components is still a valid one.
The author recommends that if you do purchase a motherboard as a part of building or upgrading a PC,
you should get one that has as few peripheral components as possible.
The user can decide which brands, what level of quality, and what level of cost they wish to
spend on their system.
With a custom built PC, the user can decide which brands and models of devices are installed into the
system, and he/she can decide what level of quality is built into the PC. One can buy an inexpensive
component now, and purchase a more expensive component at a later time when funds become
available.
The same name-brand components found in pre-built name-brand PCs are also found in
custom-built PCs.
Some people, when purchasing a PC, consider a name brand on the front of the case as a guarantee of
a quality computer. This is not necessarily true. The same kinds of name-brand components, such as
memory, hard drives, and motherboards, are found in custom-built PCs. In fact, customers who build their
own PCs usually do extensive research to find out which brands of components are the best, so that they
can build them into their new computer.
If you know the quality of a name-brand component and how it compares with other brands, you can
make intelligent decisions about what you do or do not want in your home-built PC.
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William A. Lloyd
There are some simple rules you should use when you are preparing to buy and/or build your own PC:
1)
Know what you want BEFORE you go looking or buying. Many people get convinced they
need a more expensive or "powerful" computer, when in fact they do not. People who do word
processing for a living do not need an Intel Core i7-based computer necessarily; an Intel Core
i3-based PC will do just fine when buying new. DECIDE WHAT YOU WANT THE COMPUTER
FOR BEFORE YOU BUY IT! Let your software choices and intended uses of the PC drive your
purchasing choices, not what some salesman says. If necessary, bring a knowledgeable person
along who can help to sort out the truth from the noise.
2)
Comparison shop different stores: DO NOT buy on impulse. Write down what you want to
buy, being as specific as you can. Compare the prices quoted by the vendor; call the company if
necessary and have them give you a price quote. Many will even fax you a price quote. If you like
a system and it is $40 more than a competitor's price, see if they will match the price - many will do
this. Take at least two weeks to go through this process.
3)
Get ALL promises for service & support IN WRITING before buying the PC. Verbal
agreements between you and the salesman are never binding in a court of law, if things should
get to that point. Therefore, get any warranties, service agreements, and support agreements IN
WRITING before you buy your PC. Speak to a supervisor or manager if necessary, but do not
accept any verbal agreements as binding commitments.
4)
If you have a vendor build the PC for you, test the computer before it leaves the store.
Nothing is more frustrating to the new computer owner than to find that the 3.0Ghz Core i7 system
will only run at 2.0Ghz, or that your DVD drive doesn't work, or that your monitor has squiggly lines
all over it when you leave it on for more than 10 minutes. The store should have already tested the
computer before you pick it up, but this isn't always necessarily the case. It only takes 5-10
minutes to assemble the system and test everything; insist on doing this.
Use a diagnostic program to check and evaluate the operation of your computer. If something is
not right, insist that the vendor correct the problem BEFORE it leaves the store. Use the same
rules when buying a used computer from someone's home: run diagnostic software on it BEFORE
you pay for the unit.
5)
Properly configure your application software BEFORE you venture into the PC world.
The main reason new PC owners get so frustrated is that they don't know how to get in and out of
their new application programs. Have the store or some well-trained PC maintenance person set
up the programs on your hard disk. By doing this, you will be able to use your programs
immediately. Recommend that the user take introductory classes at a community college or
training facility, so that they can get the maximum benefit from their new computer.
Above all, CAVEAT EMPTOR (Let the buyer beware!).
On the next page is a basic checklist for building a PC from scratch. Use this as a guideline for the basic
assembly of your new computer.
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William A. Lloyd
NEW PC BUILDING CHECKSHEET
Tools and parts needed:
o
Flat/Phillips screwdrivers, and an ESD wrist-strap
o
Needle-nose pliers and/or wire cutter
o
Case/power supply (including mounting screws, plastic standoffs, and drive mounting hardware)
o
Motherboard and CPU, floppy and hard drives, memory, drive cables, audio cables, video card,
CD-ROM drive, sound card, fax/modem, CPU cooling fan
Software needed:
o
Some kind of diagnostic or system testing program (like the course diagnostic DVD)
o
A Windows or Linux operating system installation CD or DVD
o
Any desired application software
o
Installation disks for the new sound card, CD/DVD-ROM drive, video card, and other devices
o
An audio CD, data CD-ROM, and a DVD-ROM disk (for testing purposes)
Step-by-step instructions:
1)
2)
3)
4)
5)
6)
7)
8)
Open the computer case;
Mount motherboard to case using plastic standoffs, as well as bronze standoffs and mounting
screws (be sure to use screws only on grounding points - use plastic standoffs elsewhere); the
motherboard MUST be flat, steady, and not grounded out against the case. Be sure that the heat
sink and fan assembly is properly attached, and that a small amount of heat sink grease is applied
to the top of the CPU before attaching the heat sink;
Attach the power supply connection to the motherboard, and attach the speaker connection; test
the motherboard to see that it is working correctly (it should give three (3) long beeps, provided
that no memory is installed); power down the PC;
Install the DIMMs (memory modules) onto the motherboard, and apply power again; you should
get an audio error code (a series of beeps) indicating there is no video card installed; if there is no
change, check the installation of the DIMMs; if correct, power down the PC;
Install the video card, and attach the monitor; power up the PC and watch the monitor to see that
POST is testing the PC; if there is no change, check and/or replace the video card; if correct,
power down the PC;
Mount all drives to the case; attach drive cables to the drives, and then attach the cables to the
interface card or motherboard; be sure to install any IDE/EIDE cables so that the stripe on the
cable is closest to pin 1 on the connector; be sure to attach power cables to all drives;
Power up the PC, and enter the CMOS setup program; enter into the program the exact types of
hardware found in the PC (specifically video, memory size, floppy/hard drive parameters, etc.);
save the information to CMOS RAM and reboot the PC;
Boot the PC from the Windows (or Linux) installation CD or DVD; begin the operating system
installation process, partition and format the hard drives, and install the drivers for any other
installed equipment (CD/DVD-ROM, sound card, video card, fax/modem, etc.);
*
Use the installation checksheets found in chapter 5 of this text for installing hard drives,
CD-ROM drives, sound cards and fax/modems; these check sheets will assist you in the
PC building process. Also, refer to Chapter 5 of this text for a list of the steps involved in
preparing a hard disk for use.
9)
Run some kind of diagnostic software to ensure that the PC is working properly; also, run a
burn-in test program for 12-36 hours to check the system under load conditions;
Replace the computer case - do NOT install the cover until you know the system is working
properly.
10)
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William A. Lloyd
Installation tips:
1)
2)
3)
4)
Take things one step at a time. Do not rush, and do not proceed to the next step until you are sure
that what you just installed is working properly;
Make notes of what you do, and observe the little things; for example, notice that the wires to the
dashboard lights on the case usually are labeled to show what they are, and that the motherboard
(and/or the motherboard documentation) indicates where the wires should be plugged; notice
beep codes, error messages on the screen, and funny smells;
Be sure to have the 800-numbers and support website location for the hardware manufacturers
available (whenever possible) for technical support if needed. Also, have the name and telephone
number of the hardware vendors for the devices you are installing in your PC; if any troubles
occur, contact the vendor for assistance.
Refer to the various installation checksheets for different devices (hard disks, sound cards, etc.)
to assist you in each step of the PC building process.
Some additional tips concerning the proper way to install a motherboard to the case:
Plastic standoffs
When you install a motherboard, DO NOT screw it directly down to the chassis of the case!
You mount it to the case, using the little plastic standoffs provided when you buy the case and power
supply (if you do not have any, let the instructor know; you also can obtain these standoffs from local
hardware vendors). These standoffs keep the board from shorting out against the case, and they provide
enough stability to the board so that you can push cards into the bus connections. If you do not install the
standoffs correctly, any of the following things could happen:
o
o
o
the board touches against the case and shorts out, potentially damaging the motherboard and
other installed components
you crack the motherboard when installing the cards into the bus connections
you allow the board to warp into an unnatural position by leaving it unsupported
The plastic standoffs have two ends to them: one that snaps into the holes on the motherboard, and one
end that goes into little slots or grooves on the case. The idea is to have the bottom part of the standoffs
slide into the pre-made holes on the case.
If you find that there is a need for a plastic standoff, BUT there is no hole on the case for it,
cut the bottom off of the standoff, and let the standoff rest on the chassis. This will ensure that the
motherboard doesn't touch the case.
Grounding points
On most motherboards, there are CERTAIN holes that are designed as grounding points, that are
intended for you to screw the motherboard down to a metal standoff on the case. These grounding
point holes usually have a silvery-appearance around them. They are designed to take either a
metal screw or a plastic standoff when mounting the board. When using a new case, you will find a
bronze metal standoff (or two) in the package of screws that comes with the case. You will usually need to
mount only one of these bronze standoffs on the case, and mount the motherboard with a metal screw at
that point only.
If you mount a metal standoff and a screw into a hole that is NOT a grounding point, you can short out the
motherboard and PERMANENTLY damage it. Be very careful to notice the appearance of the holes in
the motherboard, and never screw the board down to a hole that is not a grounding point.
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Power supply connections
On ATX-style power supplies, the main 20-wire (or 24-wire) plug to the system board has been designed
into a single connector, so that the user has only one connection to make on the system board. Further,
the connector has been keyed so as to go onto the system board only one way. If the connector does
not appear to be plugging in correctly, try turning the connector around. If your power supply has an
additional separate 4-wire plug to the system board, it too has been designed to connect only one way.
Be sure to install both the 20-wire (or 24-wire) and the 4-wire connectors before powering up the system.
Mount the motherboard and apply power first ...
When installing the motherboard to the case, use the proper guidelines for mounting the motherboard to
the chassis. Make sure the heat sink assembly and fan are properly installed, and that a small amount of
heat sink grease is applied to the top of the CPU chip before mounting the heat sink.
Then, attach the power supply connections and the PC speaker ONLY: no RAM, no video card, etc.
Power the system up and listen for 3 low-toned beeps. If you hear these beeps, the motherboard is OK
(it powers up and finds the CPU). If you hear no beeps, check your power and speaker connections,
ensure the CPU is installed OK, and make sure the board is not grounding out. If this does not resolve the
problem, replace the motherboard.
Then, install the memory ...
Install the memory to the motherboard; be sure to put it in the right DIMM sockets (look for the designation
"BANK 0"). You may need to set some jumpers on the board to get the memory to be recognized
properly; also, many boards require more than one DIMM on the board at a time.
Once you install the memory, power up the system and listen for a different set of beeps (usually 2 high
short beeps and 7 or 8 lower-toned short beeps). These beeps are telling you that the video card cannot
be found (mainly because it has not been installed yet!). If you get such a beep sequence, you can
continue and install the video card. If you still get the three low beeps as before, check and re-install the
memory. If the memory is installed correctly and you continue to get only the three low beeps, replace the
memory.
Then, install the video card and monitor ...
When you have the motherboard and memory installed correctly, then you can install the video card into
the system and attach a monitor. When properly installed, you should be able to see the computer going
through POST on the screen.
If not, then you may have a problem with the video card (check for one long and three short beeps) or the
monitor. If the system hangs after installing the video card, the video card is probably defective, or not
installed correctly. If you see no video on the screen after checking the video card, then either the monitor
is off (or without power), or the monitor is defective.
Then, install the hard drives and optical drives...
Once you have motherboard, RAM, and video installed properly, attach the hard drives and optical drives
to the drive controller/interface. Be sure to attach the IDE/EIDE cable stripes next to pin 1 on the drive
interface connectors, or the SATA cables to the drives and motherboard. Also, be sure to attach power
cables to the drives.
You may now also install the keyboard and mouse.
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Then, power up and run the CMOS Setup program on the BIOS ...
When the drives are fully connected, then run the Setup program. Watch the screen to tell you what
keystrokes to use in order to enter the Setup program. Use the "Auto-detect" feature to detect the
IDE-class or SATA hard drive(s) in your system. If the auto-detect feature does NOT find the hard
drive(s), then power down and re-check your connections.
If the computer still cannot find the hard drives, then either your cables are bad, the on-board drive
controller is bad, the power to the drives is bad, or the drives themselves are bad.
If the drives are recognized by the auto-detect feature, save the setup information and reboot. You can
now begin loading the operating system onto the PC, and begin software loading as well.
Refer to Chapter 5 of this text for more information on the steps involved in preparing a hard disk for use
in a PC or a laptop.
Building a PC for different kinds of uses
Depending upon what you want to do with the PC you build, you will need to configure it specifically for
the kinds of work you wish to do with it. There really is no “one size fits all” type of computer. For the A+
examination, you will need to know how certain types of computers need to be equipped. Specifically:
Graphic / CAD / CAM design workstation
This type of computer will design and render complex graphics, and/or will be used with computerassisted design or manufacturing applications. This typically requires a multicore processor (an i5 or
better), a high-end video card, and as much RAM as the system can accommodate. A system lacking in
these specifications will suffer from poor performance when running these kinds of applications.
Audio/Video editing workstation
Audio and video files can be extremely large. A specialized audio and video card designed for
manipulating these kinds of files, along with a large fast hard drive and dual monitors will ensure optimum
performance.
Virtualization workstation
Computers that work with virtualized operating systems require a lot of system resources, A virtualization
workstation should have the maximum amount of RAM and CPU cores possible, to prevent slow
performance.
Gaming PC
A gaming PC needs to be extremely fast, powerful, with a video card that can handle complex graphics,
all while staying cool. A multicore processor, a high-end video/specialized graphics processing unit (GPU),
and a high definition sound card are required. A high-end cooling system, including multiple fans on the
case and a robust CPU heat sink and fan, are also necessary.
Home Theater PC
A home theater PC should provide the user with a high-quality experience that rivals what one would
experience in a movie theater. Surround sound audio, a video card with HDMi output, a TV tuner card to
pick up over-the-air and cable broadcast signals, and an HTPC compact form factor are all required for
such a computer.
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Standard thick client
A standard “thick client” PC has the standard, run-of-the-mill operating system on it, like we have all seen
before. Desktop applications need to have enough resources to run efficiently, and it needs to meet the
recommended requirements for selected operating system.
Thin client
A “thin client” computer has only enough RAM to run the most basic operating system. Hard disk space
is at a minimum, and an optical disk may not even be installed on such a PC. A thin client operating
system is designed to let the user log into a network or virtualized environment that is on a private or
public cloud. Only the most basic of applications will be installed on such a PC. It needs to meet the
minimum requirements for selected OS (like the Windows Thin Client OS), and it needs network
connectivity.
Home Server PC
A home server PC is much like any other file server. Media streaming, file sharing, and print sharing all
need to be supported. This would require a gigabit NIC, and perhaps even a RAID array for data storage
needs.
All of these types of PCs may be mentioned in the A+ certification examination.
NOTES
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Chapter 8. Printers
This section of the text will discuss the operation, maintenance and repair procedures for the six main
types of printers in the market today: dot matrix printers, ink-jet printers, thermal printers, laser printers,
wireless (wi-fi) printers, and virtual printers. There will be a number of questions on the A+ examination
about how certain types of printers operate, how they are to be serviced in the field, and how you should
properly install a printer onto a computer system.
Impact / Dot-matrix printers
Dot-matrix (impact) printers use an electromagnet within an adjustable print head to fire a series of wire
pins against an inked ribbon, which in turn impacts upon the paper which is mounted on a platen (a hard
rubber roller). Dot matrix printers use either 9, 18 or 24 pins to fire from the print head onto the ribbon
and paper; the more pins in the print head, the better the quality of printing. 18 and 24 pin printers are
considered letter-quality printers, while 9-pin printers are considered near-letter-quality printers.
Even though ink jet printers and laser printers are commonplace now, dot matrix printers still serve useful
purposes in the computing community. Many businesses use dot matrix printers to print multi-part
carbonless forms, so that both the vendor and customer have duplicate copies in one printing pass.
Ink jet printers
Ink jet printers use a piezo-electric crystal or similar mechanism to shoot a stream of pressurized ink from
a nozzle onto the paper. The quality of ink jet printers can rival laser printers, and ink jet printers can also
produce color printing output as well. The major drawback of ink jet printers is that the ink jet nozzle can
become clogged over time, and the ink cartridges usually will not print more than 100 pages before
needing to be refilled or replaced. Further, most inks used by ink jet printers are water-soluble, and the
ink can run if the page becomes wet.
Thermal printers
As the name implies, thermal printers use heat to transfer an impression onto special kinds of paper. You
likely will encounter thermal printers everyday: many receipt printers at point-of-sale terminals are
thermal printers. Also, older fax machines that used rolls of paper typically are thermal printers.
There are two main kinds of thermal printers:
Thermal wax transfer: a printer that adheres a wax-based ink onto paper. A thermal print head melts
wax-based ink from the transfer ribbon onto the paper. When cool, the wax image becomes permanent.
This type of thermal printer uses an equivalent panel of ink for each page to be printed, no matter if a full
page or only one line of print is transferred.
Monochrome printers have a black ribbon page for each page to be printed, while color printers have
either three (CMY) or four (CMYK) colored panels for each page. Unlike thermal dye transfer printers,
also called dye sublimation printers, these printers print images as dots, which means that images must
be dithered first. As a result, images are not quite photo-realistic, although they are very good. The
advantages of these printers over thermal dye transfer printers are that they do not require special
paper, and they print images faster.
Direct thermal: a printer that prints the image by burning dots onto temperature-sensitive coated paper
when the paper passes over a line of heating elements. Early fax machines used direct thermal printing,
as do receipt printers commonly used at point-of-sale (POS) terminals. Note that thermal printers are
sensitive to high and low temperature extremes.
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Laser printers
Laser printers use an electro-photostatic (EP) process to deposit and fuse onto a piece of paper an
image transmitted from the computer. Paper and toner are given opposite electrostatic charges, which
causes the toner to adhere to the page. A heat roller melts the toner into the paper, to permanently affix
the image to the paper before it is ejected from the printer. The process is similar to that used in
photocopiers, except the image is transmitted from the PC and not placed on a glass for scanning.
Stages in the laser printing (EP, or electro-photostatic printing) process
There are six distinct stages involved in creating a printed page with a laser printer. Listed below is a
description of each of these six stages. These stages are required knowledge for the A+ examinations:
1) Conditioning phase
In this phase, a uniform negative electrical charge is applied to the drum unit within the laser printer (or
within the toner cartridge). At the same time, a uniform negative charge is also applied to the paper as it
passes by the corona wire (or corona transfer roller) within the printer. This will permit the image to be
electrostatically transmitted from the drum to the page during the transfer stage, when positively-charged
toner will be attracted to the page.
2) Writing (or exposing) phase
In this phase, the laser diode within the printer writes (or exposes) an image to the drum; this image is
what will be written out to the paper, once the toner is applied to the drum and transferred to the paper.
3) Developing phase
In this phase, the portion of the drum that was written to by the laser is exposed to toner. The toner is
attracted to the image written on the drum by the laser, and the toner image is created. The toner dust has
a positive charge, and will be attracted to the drum.
4) Transfer phase
In this phase, the image on the drum (which is just toner dust arranged into a pattern) is electrostatically
transferred from the drum to the paper. Specifically, the positively-charged toner is attracted to the
negatively-charged paper, and the image is laid out upon the paper. The charge on the paper has a
greater potential than the charge on the drum, and so the image is transferred to the paper.
5) Fusing phase
In this phase, the paper (with the toner applied to it) is quickly heated by the fuser assembly, and the toner
image is pressed into and melted onto the paper. In this way, the image is permanently preserved on the
page.
6) Cleaning phase
In this phase, the drum unit is cleaned of any excess toner, and the negative charge on the drum is
neutralized. Also, on the heat roller in the fuser assembly, a cleaning bar cleans and lubricates the heat
roller to ensure that heat will be applied evenly on the next page.
Some versions of the A+ practice exams place the cleaning phase at the beginning of the six-step
process, instead of at the end ... in any event, the six stages themselves are all the same.
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Wireless or Wi-fi Printers
Wireless or wi-fi printers typically will be either an ink-jet or laser printer. However, they do not physically
connect to a PC or a laptop. The computer will address the wi-fi printer by virtue of an IP address (given
to the printer by the nearest wi-fi router), or by virtue of the media access control (or MAC) address
embedded in the ROM of the printer’s wireless network card. Software and drivers provided by the
manufacturer will allow any device, not just a PC or laptop, to accept print jobs from a connected device.
The printer does not need a physical connection to a computer or router in order to print a document.
Networked (wired) printers, by comparison, may allow print jobs to be submitted from wired or wireless
devices. However, these printers typically are connected to a network router which intercepts the request
and sends it to the device via an RJ-45 cable. Depending upon the kind of network, the printer may be
directly connected to the router, or be connected indirectly by way of a hub or switch that eventually
connects to the router.
The A+ examination requires you to know the difference between a networked printer and a wireless or
wi-fi printer. You will be expected to know how to install such a printer, and how to troubleshoot
connection issues with a wireless printer, in addition to troubleshooting other kinds of printers.
Virtual Printers
A virtual printer is not actually a printer at all. It is a piece of software that takes a document (i.e., a Word
document) and converts or “prints” the document into an Adobe .PDF file, or into an image file (like a
.JPG file), or into some other printable format. Virtual printing allows the user to take a document in one
format and convert it into another, without having to obtain and install a second application product.
Typical uses of virtual printers include:
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Saving a document to another format such as an Adobe .PDF file: For example, a word
processor may not be able to include an engineering CAD document, but it could include a .TIFF
or .JPG image of that document which was virtually printed from the engineering software
package.
Saving multiple documents into a single document: saving a web page into a single
document as it appears in the web browser will capture the relevant content without relying on it
being available or functional in the future.
Saving a reference copy of a document for longer term access: this would allow the
document to be viewable by non-proprietary software in the future.
Saving a document in a non-editable format: A draft of a book may, for example, be saved in
a .PDF format as a .TIFF image, which would make it more difficult to copy the text of the book.
Sending documents to a fax server
Allowing user to control certain aspects of printing not supported natively, such as printing
multiple pages per sheet without border, printing a letterhead, printing watermarks, and so forth.
This output can either be saved in a file for future printing or passed on to another printer.
Saving paper and ink while testing how something will print
Allowing remote printing of documents over the Internet: At least one example of this
technology creates a virtual printer on one computer, which converts the document and sends it
to a server on the Internet, from which the file can be sent to a printer attached to a PC in a
remote location. Similar technology is used to allow printing from devices such as smart phones.
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Perhaps the most commonly used virtual printer is the Adobe .PDF Writer application. This software can
be obtained by purchasing any of the popular Adobe products, such as Acrobat or Captivate. There are
open-source products available as well that will allow the customer convert their document into an Adobe
.PDF file.
Basic printer troubleshooting guidelines
Here are some typical problems you might encounter with a faulty laser printer:
Conditioning problems:
Writing problems:
Developing problems:
Transfer problems:
Fusing problems:
Cleaning problems:
No image is written to the page, since the electrical charges were not
applied correctly
Image is poorly laid out, spotty, has gaps in it, or the image is absent. If
the laser is “solid on,” then thewhole page will be black
Poor image, weak image, spots on page or excess toner problems
No image is written to page; clumps of toner spot the page
Image wipes off the page
Residual images are printed on page; excess toner builds up inside printer
Always refer to the laser printer’s technical or user guides for guidance on printer error codes and repair
procedures ... not all laser printers are made alike.
Troubleshooting laser printer problems
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Clean out excess toner with a printer-certified vacuum cleaner
Check for and remove paper dust and paper shreds
Make sure paper pick-up rollers are clean, and that they have no flat spots; replace if necessary
Use denatured alcohol, not rubbing alcohol, to clean pickup rollers
Use compressed air to blow dust away from optical and mechanical sensors
Vacuum or clean the ozone filter of dust and particulate matter
Check toner cartridge; replace if necessary. CompTIA does NOT
recommend using or installing remanufactured toner cartridges
Check darkness/contrast adjustment; make any necessary corrections
Print a test page for the customer to show proper operation
If the Windows printer driver for that make of printer does not work correctly, use an HP LaserJet
III driver (or similar OLDER HP driver); virtually all laser printers have an HP LaserJet III emulation
mode that should work with that printer
If you are having printer driver problems, contact the manufacturer of that printer for information
on how to get a correct or updated driver for Windows (either Windows XP, Vista, 7 or Windows
10 ... one driver does NOT fit all shades of Windows!). These drivers are usually available off
the Internet, from the company's web site.
Problems with ink-jet printers
One of the worst things a user can do with an ink-jet printer is to sporadically use it. When an ink cartridge
is allowed to print for a time and then sit idle for a week or more, ink can form clogs in the cartridge and
the nozzle assembly. Some printers have a “cleaning feature” that can reduce or remove clogs from the
nozzle assembly, but many do not.
If you encounter a printer that is clogged with old ink, remove the ink cartridge, and use some denatured
alcohol or an ammonia-based window cleaner in the cartridge carrier within the printer to clean out any
encrusted ink deposits. You may need to gently clean the ink cartridge before reinserting it into the printer
as well.
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Also, CompTIA does NOT recommend the use of refilled or remanufactured ink (or laser toner)
cartridges. If a customer is manually refilling ink cartridges, or if they are using remanufactured
cartridges of poor quality, you likely will have problems with leaking ink or toner within the printer.
If you find a printer has a problem with ink leakage within the device, immediately remove the ink
cartridge. Use some ammonia-based spray cleaner and lots of paper towels (and q-tips for tight spaces)
to clean up the leaked ink. It will be very messy, so wear clothing that is appropriate to dirty work.
Once the mess is cleaned up, install a new, OEM ink cartridge and print several test pages. The first few
pages will reveal where any additional cleaning need to be performed. Guide the customer towards a
vendor that can provide reasonably-priced OEM cartridges, and/or reliable remanufactured ink
cartridges.
Finally, never leave paper sitting in an ink-jet (or laser) printer for weeks or months on end. The paper will
absorb moisture from the air, and likely cause paper jams. Also, the inserted paper may cause a flat spot
to develop on the pickup rollers. If the printer is to remain out-of-service for more than two weeks, remove
the paper from the unit.
Troubleshooting dot matrix and ink jet printer problems
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Check the print head, especially if the print quality is poor. If the head has a lot of ink buildup on it,
clean the head with denatured alcohol and a soft toothbrush. Make sure the pins in the dot matrix
print head move freely. Make sure the jet nozzles on the ink-jet printer are clean.
Check the ribbon in the dot-matrix printer; if the ribbon appears worn in spots, or if the print quality
is light or imperfect, replace the ribbon. Re-inking the ribbon should be a last alternative.
CompTIA does NOT recommend the re-inking of printer ribbons.
Check the ink cartridge in the ink-jet printer. If the print quality is poor and the print head appears
clean, replace the cartridge. Note that some ink cartridges can be re-filled, but also know that
some inks are of poor quality. The printing will never be better than the quality of ink you put in the
printer. CompTIA does NOT recommend the use of refilled ink cartridges.
Use denatured alcohol, not rubbing alcohol, to clean pickup rollers
Check for stray bits of paper. Small shreds of paper will cause paper jams if not removed. Also,
recommend that users buy decent quality paper; cheaper recycled paper leaves paper dust which
causes paper jams and affects the performance of optical or mechanical sensors within the
printer.
Make the printer print a test page; show the customer that the printer is working correctly.
Make sure the software you use is specifying the correct printer driver; using the wrong printer
driver will cause poor/slow printing, or no printing at all.
Other important tips
Make sure you have the manuals for the printer when servicing it; printers may have complex paper paths
inside them, or special programming interfaces that require attention to fix the problem.
Check the pickup rollers; if they have flat spots or do not pick up the paper correctly, clean them with
denatured alcohol. If the problem persists, replace the pickup rollers.
Check any sensors within the printer; a malfunctioning sensor (optical or mechanical) can shut down the
printer completely. Clean optical sensors with denatured alcohol, and blow dust away from any kind of
sensor. Replace the sensor if it has become defective.
Call the printer manufacturer and/or visit the company’s support website location for technical assistance
when necessary.
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Installing printer drivers
Microsoft has gone to great lengths to provide in the operating system a wide variety of drivers for
hundreds of different printers. With the advent of plug-and-play capable printers, you may find that
Windows already has a driver that will work with your printer.
HOWEVER, you may find that the Original Equipment Manufacturer (OEM) printer driver will give better
quality printing and more reliable operation than the Microsoft-supplied driver that comes with the
operating system. It is recommended that you use the OEM printer driver disk when installing a new
printer on your PC or network.
Further, for USB-style printers, you likely will need to run this installation CD BEFORE attaching the
printer to the computer. This will ensure that the printer is properly recognized by the operating system,
and it will reduce the likelihood of errors and problems during the installation process.
If you do not have the printer driver installation CD/DVD, contact the manufacturer or visit the
manufacturer’s website to download the necessary software.
If you have an all-in-one (AIO) printer, you may find that the device will use a portion of your system
memory, because the AIO printer does not have any built-in memory. Traditional printers (ink-jet and
laser) generally have a fixed amount of memory installed on them, and many have the capability of
adding additional memory to them.
By adding memory to a printer, you increase the printer’s speed and overall performance when
generating complex images on a given page. However, many AIO printers simply rely upon your system
memory in the PC to buffer the print job to the device.
If your PC becomes significantly slower after installing an AIO printer, you may need to install additional
memory on the system board to compensate for this issue.
NOTES
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Chapter 9. Laptops and Tablet Computers
Laptop computers are becoming more and more popular with users. Not only have these types of
computers become smaller and more lightweight, they also have become as powerful and flexible as
traditional desktop computers. The advantages of laptop computers are easy to see: they weigh less than
five pounds, they can be transported by one person almost anywhere, they can connect to the Internet
and traditional networks, they can be as fast as desktop computers, and their price is not necessarily
much more than a desktop computer and monitor.
Some laptops include cellular, GPS and Bluetooth capabilities in them. Newer laptops allow the user to
place the unit in “airplane mode,” so that it can be used safely while in flight. Docking stations allow the
laptop to operate like a traditional desktop PC, connected to a monitor, keyboard and mouse. Some
laptops also have rotating, swiveling or even removable screens, to enhance the usability of the device.
There are disadvantages associated with laptop computers as well. Because they are easily taken from
one place to another, they are more prone to being dropped or suffering various kinds of physical abuse.
Repairs to laptop computers can be very expensive, because of the proprietary nature of laptops. No two
laptops are exactly the same, and as such replacement (or upgrade) parts can be difficult to obtain. The
LCD screens installed in laptop can be broken easily, and replacement costs are high. Most of the time, if
the laptop must be repaired, one must take the laptop to an authorized service center for that brand of
computer; this means the labor and parts costs will be high, and third-party parts (such as memory or
hard disks) will not be available for installation.
Despite these problems, laptop computers continue to grow in popularity. In this section of the text, we
will briefly discuss some of the key differences between laptop and desktop computers.
PC Card (PCMCIA) and USB peripherals
Many laptops have PC card connectors built into them. These connections are also known as PCMCIA
connectors. PCMCIA stands for the Personal Computer Memory Card International Association, a group
that developed the standard for adapter cards laptop and portable computers. These adapter cards are
about the size of a credit card. PC Card devices include fax/modems, expansion memory, network
interface cards (NICs), radio transceivers, hard disks, and solid-state storage devices.
There are three types of PC Card devices: Type 1 are the thinnest, Type 2 are slightly thicker, and Type
3 are the thickest. PC Cards may be thicker because of the type of integrated circuitry built into them; the
more complex the device, the larger it becomes. Modems, hard drives and NICs are more likely to be
Type 3 devices, while memory cards may only be Type 1 devices. This issue IS covered on the A+
examination.
In many cases, USB ports are replacing PCMCIA ports as the option of choice for laptops. USB wireless
NICs can be obtained inexpensively for use with laptops (or desktop PCs), just as PCMCIA wireless NICs
have been available for years. Some manufacturers have discontinued building laptops with PCMCIA
connectors in favor of USB adapters. Extra USB ports also allow the user to attach flash drives and
external CD/DVD-ROM drives to the laptop.
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Batteries and AC adapters
Laptop computers utilize batteries to keep them running for several hours at a time. The typical laptop
battery will operate the computer for 3 to 3.5 hours. Nickel-cadmium (NiCd) batteries are the heaviest
batteries available. NiCd batteries have a problem in that they have a "memory effect"; that is, unless you
drain the battery all the way down to zero, the battery may not fully recharge, and this can lessen the
charge life of the battery.
Nickel Metal Hydride (NiMH) batteries are generally the lightest in weight. NiMH batteries do not
generally suffer from "memory effects", and as such recharge fully when plugged into the AC adapter or
charger assembly. Newer battery technologies extend the operating capabilities of laptop computers.
Laptop batteries should have a life span of 18-24 months when used on a regular basis, and longer if they
are used more occasionally. If a battery will not hold a charge, if it appears to be bulging and swollen, if it gets
very hot, or if the charge level test button blinks several times, it needs to be replaced.
Replacement batteries can be obtained from the manufacturer, as well as from various retailers on the
Internet. Replacement batteries from the manufacturer will cost significantly more than third-party
replacements available on the Internet. Simple searches on eBay and Amazon will help you locate
reputable third-party replacement batteries.
Whenever possible, avoid keeping a laptop continually connected to the AC adapter, particularly when
the laptop is not in use. Continually charging a laptop battery while the unit is not in use will have a
detrimental effect on the overall charge-holding capability of the battery. When a laptop battery is
replaced with a new one, recycle and dispose of the old one in an environmentally-responsible manner.
AC adapters allow the laptop to be powered directly from the wall current. The adapter converts the 110
volts of alternating current (or 220 volts overseas) into direct current which both powers the laptop and
charges the battery. AC adapters generate a fair amount of heat, and are prone to fail when exposed to
excess line voltage or surges.
If a laptop fails to recharge properly or does not power up properly, you should use a volt-ohm meter to
check the voltage being put out by the AC adapter. If it is not outputting the specified voltage, you will
need to get another adapter. The voltage that the adapter outputs should be specified on the adapter
itself, or specified in the documentation for the laptop.
Unfortunately, many manufacturers make their adapters to be proprietary, so that you must purchase a
replacement adapter from the laptop manufacturer. Be sure that the adapter you purchase exactly
matches the plug and the required output voltage; otherwise, if the voltage is incorrect, you could
potentially damage the laptop.
Also, be aware that some users tend to be aggressive when plugging and un-plugging the AC adapter
plug into the side or back of the laptop. Inserting the power cord too forcefully will cause this plug to break
off from its electrical connections on the system board. If the AC adapter plug within the laptop breaks off,
it is NOT a simple or inexpensive repair.
Typically the laptop will have to be sent back to the manufacturer for a “depot repair,” which will cost up to
$250.00 and take 7-14 business days to complete. The AC adapter plug on the laptop’s system board is
only soldered onto the board; it is not screwed or bolted down.
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The high-precision soldering equipment needed to make this type of repair can cost in excess of
$2,000.00. This is not a typical repair you can do with a 15-watt soldering iron. There are a growing
number of service vendors that will perform this repair; check in your local area to find such technicians.
LCD screens
Laptops usually can be connected to an external monitor, but their primary display device is the liquid
crystal display (LCD) panel built into the unit. LCD displays use a liquid crystal mix sealed between two
pieces of polarized glass. The polarity of the liquid crystal changes because of electrical currents passing
through the liquid that changes the amount of light that passes through the display.
LCD screens must use either reflected light or a backlight to illuminate them, mainly because these
displays do not generate any light. There are two main kinds of LCD panels currently in use today:
active-matrix panels and thin-film transistor (TFT) display panels. Both types of displays provide true
color display and fast refresh rates. Some display screens even will interface with a stylus pointing
device, or will accept touch input from your fingers.
LCD screens are highly susceptible to damage from twisting or bending the display. Further, poking
fingers into the display can cause damage to the unit. Therefore, great care should be taken to protect the
LCD display from impact damage, twisting, and other types of abuse. Once the screen is damaged, the
unit must be replaced; it cannot be repaired. Replacing a laptop LCD screen can cost more than the price
of the entire laptop, and an exact replacement must be obtained from the manufacturer or reseller.
A common problem with LCD screens is that the backlight within the unit will fail. The backlight enables
the user to see the display, as the light shines through the liquid crystal matrix to illuminate the images on
the screen. Typically when the backlight fails, the entire LCD display must be replaced. Further, when an
LCD screen becomes cracked or develops solid lines through the display, it indicates that the unit is
damaged beyond repair, and must be replaced.
Most laptops enable the user to plug in an external VGA-style video device, like a monitor or projector, so
it can be used in meeting or classroom presentations. The user can enable the external display device by
using a combination of function keys on the keyboard. For example: a Dell laptop will toggle between the
laptop display, the external display unit, and simultaneous displays on both when the user holds down the
blue Fn key and presses the F8 key as well. Other laptop manufacturers use a similar strategy, like
holding down the Fn key and pressing F5 for HP/Compaq laptops.
Finally, most laptops will shut off the LCD display panel when the unit is closed. A small switch above the
keyboard senses when the lid is closed, and cuts off power to the display. If you encounter a situation
where a laptop’s LCD display does not illuminate, check the cutoff switch and make sure it is in the up
position, and not stuck in the down or closed position. Also check the Fn and function-key combinations
to ensure the laptop is diverting video to the LCD screen.
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Upgrading laptops
Upgrading (or repairing) a laptop can be difficult. Usually laptops have been designed by the
manufacturer to be proprietary, requiring the user to purchase upgrade parts from only that manufacturer.
Further, some manufacturers of laptops do not sell upgrade or replacement parts to the user community;
parts can only be obtained by an authorized repair facility for that manufacturer. When buying a new
laptop, it may be advisable to ask about how easy it will be to upgrade the laptop (i.e., more memory, a
bigger hard drive) at a later point; it may be cheaper to obtain the upgrade when purchasing the laptop,
rather than waiting 1 to 2 years later, when the parts may be less accessible and potentially more
expensive. Dell and HP laptops tend to be the easiest to service and upgrade; Toshiba and Lenovo
laptops tend to be more difficult to service.
Servicing laptops
Servicing a laptop either can be a joy, or a sorrow. Some laptops, like Dells, are designed so that an
average computer technician can replace a hard drive, keyboard, pointing interface or RAM with little
difficulty. However, some laptops (like Toshiba or HP laptops) are extremely difficult to open and access
key components. In all cases, it is very important to obtain the disassembly instructions from the
manufacturer for each laptop being serviced.
Virtually all laptops have little plastic pieces that hold portions of the outer case together; if those are
broken off during disassembly, it is quite difficult to properly reassemble the unit. Also, laptop screws are
much smaller than the ones used in desktop PCs; if they are lost or dropped, they are hard to find or
replace.
If parts for the laptop are difficult to obtain from the manufacturer, try looking on the Internet to get the
parts you need. Also check with any local vendors that specialize in servicing laptops; they can provide
you with replacement parts and advice on how to service a given unit.
Many laptops must be returned to the manufacturer for depot repairs, especially if there are problems
with the system board, AC adapter plug, or other on-board devices that are not serviceable by the typical
repair technician. Some manufacturers do not make replacement parts available to the public, and some
repair procedures require the full disassembly and re-assembly of the unit. Contact the laptop
manufacturer to obtain information on depot repair procedures and costs.
Occasionally a laptop will develop a problem with the built-in wireless networking adapter. In some
instances, the laptop has a switch on the side of the unit that enables or disables the wireless adapter.
Check to see that the switch is in the ON position if you cannot receive a wireless signal.
Also, check to see if the wireless adapter has become loose or disconnected inside the laptop case.
Most wireless adapters plug into the laptop using a connector interface similar to a SODIMM socket.
Further, there are two antenna wires that must both be connected to the wireless card for it to function
properly. Make sure the wireless adapter is properly installed, the antenna wires are firmly connected,
and the driver software is up-to-date and correct for the device.
Uninstall and re-install the driver software if you believe the laptop has been corrupted by malware or
some form of virus. In some cases, wiping the operating system and reloading it back again is the only
certain way to re-awaken a malfunctioning wireless network adapter.
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PDAs, Tablet Computers and Phablet smartphones
There is a class of small, handheld computers called personal digital assistants, or PDAs. These units,
which have become essentially obsolete with the advent of smartphones, allow the person to have an
address book, date book, journal, to do list, notepad, and other such accessories that would be on a
traditional day timer or paper organizer. Further, these PDAs can let you read and respond to your email. This is done by synchronizing the PDA to the person's desktop computer. Current smartphones
incorporate these and other useful features.
Popular PDAs and smartphones include the BlackBerry, the Apple iPhone, the Google Droid phone, and
the Palm Pre, Some of these PDAs use the Palm operating system developed by the Palm Corporation,
while others use a compact version of the Windows operating system called Windows Mobile. iPhones
use the Apple iOS operating system, and many other smartphones use the Google Android operating
system. These types of digital assistants are very popular because of their small size, their impressive
features, and their ability to interface with desktop computers, e-mail systems and also the Internet.
PDAs and smartphones have synchronization software that must be installed on a PC or laptop to
enable the sharing of data between the two devices. Also, many PDAs and smartphones are capable of
synchronizing with Internet-based data, such as a Google web-based calendar or Yahoo web-based
email systems. Many PDAs and smartphones have mobile broadband, third-generation (3G),
fourth-generation (4G) or Internet access capabilities that allow them to access the Web as easily as on a
laptop or desktop PC.
However, there is little one can do to service or repair a damaged or defective PDA or smartphone short
of sending it back to the manufacturer or cellular phone provider. As a technician, you can assist the
customer in learning how to use the PDA or smartphone, installing and configuring the synchronization
software or other applications, and trouble-shooting connection problems. But repairing one of these
devices is beyond the range and scope of most traditional computer repair technicians, and obtaining
replacement parts can be a challenge.
Tablet computers, smartphones and “phablets” (a combination of a cellular phone and tablet) are discussed
in further detail later in this textbook, in chapter 15.
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Chapter 10. Power Conditioning with UPSes and Surge Suppressors
The voltage you get from the wall socket is NOT always what you would expect ...
There are periodic fluctuations in voltage from devices going on and off in your building, problems in the
transmission line, electrical storms, bad or faulty transformers, etc. Sometimes these fluctuations in
voltage may exceed several thousand volts. When this happens, bad things can happen to good
computers (or any other kinds of electrical devices).
Let us begin with an understanding the different types of about electrical power.
What is Alternating Current and Direct Current?
Current is the flow of electrical charges (usually electrons) in an electrical circuit. When you connect a
light bulb to a flashlight battery, the current flows from the positive terminal to the negative terminal,
always in the same direction. This is called DIRECT CURRENT, or DC for short.
Electrical current from a standard 110 volt household outlet changes direction 60 times each second (50
times per second in Europe, where they use 220 volt current). Because the current flows first in one
direction and then the other, this is called ALTERNATING CURRENT, or AC for short. The power
companies use alternating current because it can be transformed to higher and lower voltages (with
transformers) allowing them to transmit and distribute power with lower losses. You can see these
transformers on the tops of utility poles.
On the standard 3-prong plug, the upper-right prong is the "hot" prong, or the prong upon which the AC
voltage is transmitted. The "neutral" prong, which alternates the current between itself and the hot prong,
is the upper-left prong. The bottom prong is a ground wire that leads to an earth ground; it is used to shunt
excess voltage from the hot and/or neutral prongs to ground, especially when a surge suppressor unit is
in use.
When the 110V current from your wall outlet reaches your PC's power supply, the voltage is transformed
into both 12VDC AND 5VDC for use in your computer. The motors in certain components within your PC
(your hard drive and floppy drive motors, for example) require 12VDC, while the motherboard and other
boards within your computer require only 5VDC. You may also note that on some PC power supplies
there is a switch that lets the unit operate on either 110VAC or 220VAC, depending upon where you live.
The problem comes when a lightning strike or a faulty transformer introduces a much higher level of
voltage onto the line than is normal. Your power supply may not be able to handle the excess voltage,
and it may pass on some of this excess voltage to the components in your PC before the unit shorts out or
overloads. When this happens, damage to your PC and it's components usually occurs. Normally the
damage is such that the electrocuted components need to be replaced.
Surge suppressors (also called surge protectors)
A surge suppressor provides a way to deal with voltage spikes. The surge suppressor has a
metal-oxide varistor (MOV) that will shunt excess voltages above a certain limit to the ground wire of your
three-prong AC power cord, where the voltage will be transmitted harmlessly to ground, thereby saving
your PC. Surge suppressors can deal with excess voltage problems, but they do not help with loss of
voltage problems. A surge suppressor should be used on ALL electronic devices, including computers
and their peripherals, at ALL times, without exception.
Electrical surges are one of the primary causes of computer hardware failures.
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When buying a surge suppressor, the most important thing to check for is the clamping voltage
of the unit. The clamping voltage is that point when excess voltage will be diverted to ground.
A good suppressor will have a clamping voltage of approximately 330 volts, and will have a Underwriter's
Laboratory (UL) listing of UL 1449. This is sufficient to protect your PC from harmful excess voltage. 330
volts is 50 percent above the highest nominal input line voltage of 220VAC.
Reliable surge suppressor are made by the following companies:
APC
TrippLite
Curtis
As long as the suppressor has the UL 1449 rating and a 330 volt clamping voltage, it will serve you well.
These should cost you between $15 and $40 in the local stores.
When purchasing a surge suppressor, buy one that also has suppression capabilities for your telephone
line and/or FiOS / DSL / cable modem line. A lightning strike can pass through your telephone / DSL /
cable modem line just as easily as it can pass through your electric utility line. When that bolt of electricity
hits your PC through your modem or NIC, it has the same or greater potential to damage components in
your computer as does a surge through your electric utility line.
A surge suppressor that has telephone / DSL / cable line suppression should only cost $5 - 10 more than
a regular surge suppressor, and it will greatly enhance the protection factor for your PC.
Uninterruptible Power Supplies
An uninterruptible power supply (UPS) has the same kind of technology built into it as does a surge
suppressor, but it also contains a large battery in it as well. The battery in the UPS will allow your PC to
continue to operate if power has been cut off to your building. The battery in the UPS and the transformer
built into it provides 110VAC to your computer (and any other components attached to it).
HOWEVER, the voltage will last only for a few minutes (5 - 30 minutes), depending on the capacity of the
battery. The more expensive the UPS, the better the battery will be in the unit, and the longer it will
provide 110VAC to your computer.
A UPS allows you to shut off your PC in a normal fashion in the event of a power failure. Higher-end units
will automatically shut off your PC for you if you are unable to get to the computer in time, before the
battery runs out.
A UPS will cost at least $100 for a low-end model, and high-performance versions can cost hundreds or
thousands of dollars.
Your purchase of an UPS should be based upon how many devices you need to keep powered up during
an electric utility failure, how long you want backup power to sustain your devices, and how much your
budget can afford. UPS units are measured in how many watts they can deliver to your devices.
To determine the level of UPS that you need, add up the wattage requirements of the devices plugged
into your UPS. You can find the wattage requirements of your devices on the manufacturer's label on the
back of the PC, monitor, printer, or other device. Then, buy an UPS that delivers an equal or greater
amount of wattage than your devices require. The greater the wattage, the longer the UPS will last and
the more devices it will support.
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If you have intermittent voltage failures in your area (i.e., the power frequently cuts off for only a second),
consider buying an UPS. It will save you immense amounts of grief when using your PC, since all the
information stored in RAM is wiped out when power is cut off.
Intermittent power problems like these occur in rural areas, or in areas where new construction is taking
place and power is temporarily disconnected in order to attach new service.
An UPS is an absolute necessity when running any kind of network-based or web-based server
equipment. If power is cut off to such a server so that it abends (that is, it shuts down abnormally), the
potential for data loss is significant.
Any kind of computer that provides shared drive or data access to customers on a network or via the
Internet MUST be connected to an UPS, so that the server can be shut down in a proper fashion in the
event of a power failure.
If you do purchase an UPS, be sure to connect it to a surge suppressor, and do not plug it directly to a
raw, unprotected AC wall jack. You want the UPS to have the same protection as any other electrical
device. Further, if you do encounter a nasty electrical surge, you would much rather spend $20.00 to
replace a surge suppressor than $100.00 or more to replace a damaged UPS.
Power conditioners
There is also a type of device called a power conditioner. These devices have a transformer built into
them that supplies a clean, unvarying stream of steady voltage. They have the ability to handle surges,
and they also deal with low-voltage or brown-out conditions on the line. They ensure that you get a
constant stream of 110V AC with extremely little variation. These devices cost anywhere from $75 and
up, and they can be most helpful in areas where there are constant variations in the line voltage from your
electricity provider.
Power conditioners are not necessary in most business and home settings where clean, steady voltage is
consistently available.
Note that power conditioners are not discussed or asked about on the current A+ examination. However,
you should know what these devices are, and why they are used.
For the A+ examination, you will need to be able to answer the following kinds of questions:






What is a surge suppressor? How does it work?
What is clamping voltage? What is the proper clamping voltage for computer and electrical
devices?
What does the UL 1449 rating for surge suppressors mean?
Which part of a 110VAC plug is the "hot" prong (right), which is the "neutral" prong (left), and
which is the ground wire (bottom)?
What is an Uninterruptible Power Supply?
How are UPS units measured, and how do you know if your UPS will support the devices plugged
into it?
NOTES
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Chapter 11. Overview of Windows, Linux, Macintosh and Virtual Operating Systems
Part 1: Windows Operating Systems
Major DOS (command-prompt) commands [some obsolete, some not]
Despite the rumors to the contrary, DOS is still alive and well, lurking beneath the graphical interface in
Windows 9x. Even Windows 2000 and above allows you to run a number of these commands from the
command prompt window. You will need to know these commands for the A+ examination.
This portion of the text will cover the major command prompt “DOS-level” commands. Some of these
commands are obsolete, and the text will note these as such. Many of these commands still are in
use even with Windows 8, so they are required learning.
You may still run into situations where customers have refused or neglected to update their operating
system software. This information should assist you in dealing with issues on these older platforms.
The ATTRIB command
The ATTRIB command lets you both view and change the attributes of a file or directory. Files and folders
can have up to four attributes: Read-only (the file cannot be edited or deleted), system (the file is needed
to boot the system), hidden (the file is not visible when performing a DIR command), and archive
(whether the file will be backed up by a system backup program).
For example: ATTRIB +R C:\CONFIG.SYS makes the file read-only, while ATTRIB -R C:\CONFIG.SYS
takes the read-only attribute off of the file. The R attribute makes a file read-only, the S attribute makes a
file a “system file” used for booting the PC, the H attribute makes a file hidden, and the A attribute marks a
file for archiving with backup software.
Simply typing ATTRIB at the DOS prompt will show all of the files in that folder, and the attributes for each
file and directory.
Running ATTRIB /? will show you all of the options available with this command.
The CHKDSK command
The CHKDSK command checks your hard disk for free space, and eliminates lost clusters of data.
CHKDSK was the predecessor to SCANDISK. Running the command CHKDSK /F will eliminate lost
clusters from your hard disk, turning this wasted space into files ending in the extension .CHK. Any files in
your root directory with the .CHK extension can be deleted, which will free up additional disk space.
Running CHKDSK /? will show you all of the options available with the CHKDSK command.
The COPY command
The COPY command will let you copy files from one place to another, and from disk to disk. For
example: the command COPY A:FILENAME.EXT C:\ will let you copy a file from a floppy disk to a hard
disk. COPY A:*.* C:\ copies all files from a floppy disk (or sub-directory) to a hard disk. COPY
C:\DIRNAME\*.* A: copies all files from a hard disk sub-directory to a floppy disk. The /V option performs
a verify operation as the files are copied, and the /Y option will prevent any question prompts from being
displayed during the copy operation.
Running COPY /? will show you all of the options available with the COPY command.
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The DEFRAG utility [obsolete]
The DEFRAG utility re-orders files on a hard disk, re-assembling fragmented files and optimizing hard
disk performance. This utility should only be run from the Windows graphical interface; click on Start, then
Programs, then Accessories, then System Tools, and then Disk Defragmenter to run the application. Only
DOS 6.0 through 6.22 has a version of DEFRAG that runs from the DOS prompt.
The DEL and ERASE commands
The DEL (or the ERASE) commands will let you delete files in a disk or directory. For example: the
command DEL FILENAME.EXT lets you delete a file. DEL *.* deletes all of the files in a disk or directory.
DEL *.TXT deletes all of the files in a disk or directory with the extension TXT. Using the ERASE
command instead of DEL will produce the same result.
Running DEL /? (or ERASE /?) will show you all of the options available with the DEL (or ERASE)
command.
The DIR command
The DIR command at the DOS prompt gives a directory of the disk and/or subdirectory you are currently
in. DIR/W gives the same information as above, but displays it WIDE across the screen. DIR/P gives a
directory of the disk and/or subdirectory one page at a time. DIR/S lets you search your hard drive for a
given filename; for example: the command DIR/S RESUME.DOC will search the entire hard disk for the
file named RESUME.DOC.
Running DIR /? will show you all of the options available with the COPY command.
Directory commands MD, CD and RD
The MD (or MKDIR) command makes a sub-directory on a floppy or hard disk.
The CD (Change directory) command lets you change directories on a floppy or hard disk; the CD\
command lets you change directories back to the root directory of a floppy or hard disk.
The RD (or RMDIR) command lets you delete a sub-directory on a floppy or hard disk; however, the
directory MUST be empty (without files or other directories) before you can delete the directory. The
DELTREE command deletes both directories and files simultaneously; exercise care when using
DELTREE, since files cannot be recovered if the directory they existed in have been deleted.
Running MD /?, CD /?, RD /? or DELTREE /? will show you all of the options available with the these
commands.
The EDIT utility
The Edit utility allows the user to manually edit text files such as CONFIG.SYS, AUTOEXEC.BAT,
WIN.INI and SYSTEM.INI. Edit is a text-based utility program, but it supports a mouse and it has
drop-down menus like other Windows counterparts such as Notepad, Wordpad, or SYSEDIT.
The Edit utility still is available in Windows XP and Windows Vista.
Running EDIT /? will show you all of the options available with the EDIT command.
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The EXTRACT utility
The EXTRACT utility is used to uncompress Microsoft-compressed files, so that the files can be used on
the system. Most Microsoft installation programs use EXTRACT to uncompress the system or application
files from the compressed files on the installation disk (rather than the commercial program called
WinZip).
Running EXTRACT /? will show you all of the options available with the EXTRACT command.
The FDISK disk partitioning command
FDISK is used to create, erase, or view a partition table on a hard disk. Normally, you will use FDISK
when you first prepare a hard disk for use, or when you wish to wipe all the data off of a disk and
completely re-format the disk.
FDISK does not allow the user to resize existing disk partitions; you will need to obtain a third-party
program (like Parted Magic on the course diagnostic disk) to change the size of existing disk partitions or
to merge partitions.
When running FDISK on a hard disk, you may choose to divide (or partition) the disk into one single
partition, or into several smaller segments. Use this following procedure when creating a segmented hard
drive: you will first create a Primary DOS partition (a bootable partition), and then make the partition
active (informing the PC to attempt booting to the drive).
Then, you will create an Extended DOS partition (a non-booting partition), and create logical drives
within that partition (assigning drive letters to segments of the partition). You will then format the drive,
individually formatting each partition on the disk.
If you wish to remove the partitions at a later time, you will need to delete the logical drives, then the
Extended DOS partition, then the Primary DOS partition in order to get back to a blank hard disk.
Re-writing the Master Boot Record
There is an undocumented feature in the FDISK command that allows you to re-write the Master Boot
Record in the partition table WITHOUT destroying the data on the disk. You will use this command if you
believe that a virus has damaged the partition table on the hard disk, and you want to attempt a rescue of
the data before dumping the hard disk and reloading your operating system. This command is shown
below:
FDISK /MBR
Running this command from the DOS prompt will rewrite the Master Boot record; the process takes less
than two seconds to complete, and no success or failure messages are displayed to the screen when the
command is finished.
Once you run FDISK /MBR, you also may want to run the command SYS C: (Enter) to restore the boot
files into the boot sector of the hard disk. Once you have performed both of these commands, power
down the computer to wipe any potential virus from memory. Then, power up the computer and see if the
system will boot to the hard disk. In many cases, this procedure will restore the hard disk to a booting
state without a reformat and reload of the operating system.
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Using FDISK with FAT32 in Windows 95 and 98 [obsolete]
If you are using a boot disk from Windows 95/OSR2 or Windows 98, the version of FDISK that came with
the operating system will allow you to create a disk partition larger than 2 gigabytes (2GB). Previous
versions of DOS and Windows 95 would only support disk partitions up to 2GB in size.
These large partition sizes are possible because the new version of FDISK creates an environment
where a 32-bit file allocation table (or FAT) can be used by the operating system. You will know if you
have the correct version of FDISK if you receive a fairly long explanatory message after invoking the
FDISK utility from the DOS prompt. At the bottom of the message screen, a question will appear that
asks:
Do you wish to use large disk support? [Y/N]
If you answer "Yes" to this question, you will enable Win 95 or Win 98 to use a 32-bit FAT, and have a
single disk partition larger than 2GB. Answering "No" will let you create an older-style 16-bit FAT with
partition support up to only 2GB.
Running FDISK /? will show you all of the options available with the FDISK command.
The FORMAT command
The DOS FORMAT command lets you format floppy or hard disks (and other media, such as ZIP drives).
However, there are a number of options available that make the FORMAT utility more useful. Listed
below are some of these options:
FORMAT C: /S /V
Formats a hard disk, making it bootable;
the /V switch lets you put a volume name on the disk
FORMAT A: /S
Formats a floppy disk, making it bootable [obsolete]
FORMAT A: /F:360 /U
Formats floppy disk to 360k in a 5.25" high density drive; the /U
switch performs an unconditional format (without checking the disk
media) [very obsolete]
FORMAT B: /F:720 /U
Formats floppy disk to 720k in a 3.5" high density drive. [very
obsolete]
FORMAT A: /Q
Performs a quick format of a previously-formatted disk (also works
on a hard disk). [obsolete]
Running FORMAT /? will show you all of the options available with the FORMAT command.
The MEM command
The MEM command shows how much conventional, reserved, extended and expanded memory is
being used in your system at that time.
MEM /? shows all of the options available with the MEM command.
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The MSCDEX command [obsolete]
The MSCDEX command lets DOS assign a drive letter to a CD-ROM drive; for this program to operate
properly, a driver for the CD-ROM drive must be loaded in the CONFIG.SYS file at boot-up. MSCDEX will
assign the next available letter for the CD-ROM drive. Using the /R: option with MSCDEX forces the
assignment of a specific drive letter for the CD-ROM drive.
Running MSCDEX /? will show you all of the options available with the MSCDEX command.
The MSD utility [obsolete]
The MSD utility gives the user a summary of the hardware configuration of your PC. This utility is
provided with Microsoft operating systems starting with DOS 6.0. Windows 2000 and above has a similar
utility called MSINFO32, which can be launched from the Run command on the Start menu.
The SETVER utility [obsolete]
The SETVER utility allows older programs to operate with newer versions of the operating system.
Some programs will not work with anything but a specific version of the operating system, such as DOS
version 5.0. SETVER actually "lies" to operating-version-specific programs, telling the program what it
wants to hear as to which operating system version is currently running. SETVER is loaded in the
CONFIG.SYS file as a device driver; for example, DEVICE=C:\WINDOWS\SETVER.EXE.
The SCANDISK command [obsolete]
The SCANDISK command checks your floppy or hard disk thoroughly for physical and logical formatting
errors, correcting any errors it finds. It can even perform a surface scan on the physical disk media,
marking as bad any sectors that have serious defects upon them.
You may notice that in Windows 95 and 98 that the DOS version of SCANDISK will run if your PC locks
up, and is unable to shut down normally. Be very cautious about agreeing to SCANDISK's request to "fix"
any problems found while examining your disk ... it's best to run the Windows-based version of the
program once you are in Windows. If all SCANDISK wants to do is clean up temporary files or reclaim
unused disk space, agreeing to the DOS-level SCANDISK's repair request should be just fine.
Running SCANDISK /? will show you all of the options available with the SCANDISK command.
The SMARTDRV utility [obsolete]
SMARTDRV.EXE is a 16-bit utility that uses a portion of your extended memory as a disk cache. This
program can improve the drive access time and system performance when the computer is running in
MS-DOS mode. However, SMARTDRV should not be run in conjunction with Windows 9x; a 32-bit disk
caching program called DBLBUFF.SYS is built into Windows 9x to perform the same task as
SMARTDRV. Use SMARTDRV only in a DOS-based environment.
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The SYS command
The SYS command writes the two hidden system files and COMMAND.COM to the boot sector of a
floppy disk or hard disk, thereby making it bootable. This process does not wipe out the existing data on
the disk. For example: running SYS A: from the DOS prompt will place the system files onto the disk in the
A: drive, making it bootable.
Running SYS /? will show you all of the options available with the SYS command.
The VER command
The VER command shows you which version of the operating system is currently running. Simply type
VER at the DOS prompt to obtain the OS version information.
The XCOPY command
The XCOPY command will let you copy both files AND directories from one place to another, and from
disk to disk. For example: the command XCOPY A:*.* C:\ /S /E /V will let you copy all files and any
directories from a floppy disk to a hard disk. The /S option tells XCOPY to copy subdirectories as well as
files; the /E option will copy even empty directories form one place to another, and the /V option verifies
that each file is written correctly before continuing.
Running XCOPY /? will show you all of the options available with the COPY command.
The CONFIG.SYS and AUTOEXEC.BAT files [obsolete]
On the following pages are typical examples of a CONFIG.SYS and AUTOEXEC.BAT file used in DOS
and Windows 95, 98 and ME operating systems (but NOT in Windows 2000 and above).
CONFIG.SYS is used by the operating system to configure your system (using 16-bit drivers) to
recognize and use specific devices in your system, such as a CD-ROM drive or a sound card.
AUTOEXEC.BAT is used by the operating system to run user-defined startup routines each time the
computer boots up. For example, the DOS-level virus checking utility may run because there is a line in
the AUTOEXEC.BAT that calls that program up each time the computer boots.
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EXAMPLE OF A TYPICAL DOS-LEVEL CONFIG.SYS FILE [obsolete]
DOS Command
[Menu]
Explanation of Commands
Displays "multi-boot" menu
MENUITEM=YCDROM, Load CD-Rom Drivers
MENUITEM=NCDROM, Do NOT Load CD-ROM Drivers
MENUDEFAULT=NCDROM, 10
Multi-boot option #1
Multi-boot option #2
Sets default and time-out
value
[Common]
DEVICE=C:\WINDOWS\HIMEM.SYS
DEVICE=C:\WINDOWS\EMM386.EXE
Extended memory driver
Expanded/UMB memory
driver
Loads DOS kernel in UMB
area
Loads DOS kernel in High
Memory Area (if needed)
Creates 10 512-byte disk
cache buffers
Creates a 50-line table to
track up to 50 files in memory
Creates 4 "look-ahead"
buffers, used for program
branching/prediction
Creates 9 256-byte stacks to
hold information when
devices are interrupted
Allows older DOS programs
to work with newer
versions of the operating
system
Program that supports
Windows networking
environment
Explicitly states name of
command processor;
sets environment size to 1024
bytes (instead of default 128
bytes)
Explicitly states last logical
drive in system
NOEMS
DOS=UMB
DOS=HIGH
BUFFERS=10,0
FILES=50
FCBS=4
STACKS=9,256
DEVICEHIGH=C:\DOS\SETVER.EXE
DEVICEHIGH=C:\WINDOWS\IFSHLP.SYS
SHELL=C:\COMMAND.COM /E:1024 /P
LASTDRIVE=F
[YCDROM]
DEVICEHIGH=C:\MTMCDAI.SYS /D:MSCD001 /P:170,15
Loads CD-ROM driver (when
user indicates in menu to load
driver)
[NCDROM]
NOTE: In Windows 95, 98 and ME, pressing F8 at boot-up will cause Windows to display a generic
"multi-boot" option screen. Use this whenever diagnosing or trouble-shooting boot-up problems.
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EXAMPLE OF A TYPICAL DOS-LEVEL AUTOEXEC.BAT FILE [obsolete]
DOS Commands
Explanation of commands
@ECHO OFF
Commands will not be displayed to
the screen as they are executed
CALL C:\NWCLIENT\STARTNET.BAT
Loads Novell IPX & NETX
PROMPT $P$G
PATH=C:\WINDOWS;C:\DOS;C:\;C:\NWCLIENT;
Prompt definition
Path definition
:YCDROM
"YES" path to load CD-ROM
driver
LH C:\DOS\MSCDEX.EXE /D:MSCD001 /M:10 /L:R
Loads CD-ROM driver;
makes CD-ROM drive
appear as R:\ >
GOTO CONT
:NCDROM
Path if CD-ROM driver is not
to be loaded
Main part of the AUTOEXEC.BAT
:CONT
LH /L:2,6384 C:\DOS\DOSKEY
Lets you repeat last 20 DOS
commands
SET MOUSE=C:\MSMOUSE
LH C:\MSMOUSE\MOUSE
Sets MOUSE memory variable
Loads DOS mouse driver
SET TEMP=C:\TEMP
Specifies location for temp files
SET RES=VGA
Sets RES memory variable
CLS
Clears the screen
C:\NET\BIN\WGTCPIP.EXE -C=C:\NWCLIENT\NET.CFG
Loads Novell TCP/IP driver
ECHO.
Displays blank line on screen
F:LOGIN Serv1\username
Logs into Novell server called Serv1
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DOS-level changes for Windows 95, 98 and Millennium Edition (ME) [obsolete]
In Windows 95, 98 and ME, the lines for MSCDEX.EXE, SMARTDRV.EXE and MOUSE.EXE will be
remarked out of the AUTOEXEC.BAT file by the Windows installer ... Windows 9x has built-in 32-bit
driver support for these programs, and the 16-bit (real mode) drivers do not need to be loaded at a DOS
level for these devices to operate in Windows.
Also, in Windows 95, 98 and ME, pressing F8 at boot-up will cause Windows to display a generic
"multi-boot" option screen. Options to boot into "safe mode", which loads the minimum driver set for
Windows, and options to boot to the DOS prompt are available by pressing F8. Use this whenever
diagnosing or trouble-shooting boot-up problems.
This above information is provided as a guide and help to you, if you encounter a PC that still is using an
obsolete Microsoft operating system version.
Questions about many of the commands listed on the previous pages will be covered on the A+
examination, and some will not. Any commands noted with the [obsolete] notation will not be
covered in the current A+ examinations.
NOTES
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Key operating system components, utilities and commands in Windows Vista through Windows 8.1
There are a number of aspects of the Windows operating system and graphical user interface (GUI) that
will be covered on the A+ exam. This also includes a number of command-line commands that were not
discussed earlier in this chapter. This portion of the text covers those parts of Windows that are key to
your success in passing the examination.
Windows 32-bit and 64-bit operating systems
32-bit refers to the number of bits (the smallest unit of information on a machine) that can be processed or
transmitted in parallel, or the number of bits used for single element in a data format. The term when used
in conjunction with a microprocessor indicates the width of the registers; a special high-speed storage
area within the CPU. A 32-bit microprocessor (and operating system) can process data and memory
addresses that are represented by 32 bits, and the memory addressing limit of these operating systems
and processors is 4 gigabytes (4GB). Any computer running a 32-bit operating system (and processor)
would not recognize any RAM greater than 4GB.
64-bit therefore refers to a processor with registers that store 64-bit numbers. A generalization would be
to suggest that 64-bit architecture would double the amount of data a CPU can process per clock cycle.
Users would note a performance increase because a 64-bit CPU can handle more memory and larger
files. One of the most attractive features of 64-bit processors is the amount of memory the system can
support. 64-bit architecture will allow systems to address up to 1 terabyte (1000GB) of memory.
Windows Vista was effectively the first Microsoft operating system to offer both 32-bit and 64-bit
versions. All current Windows operating systems are offered in 32-bit and 64-bit versions.
The primary reason to use a 64-bit operating system is to accommodate a PC with a 64-bit processor
that also has more than 4GB of RAM available on the system. In all other respects, 32-bit and 64-bit
operating systems are functionally identical.
AeroGlass
The name given to the user interface (UI) for Windows Vista operating system. The interface is referred to
as Aero Basic, and Vista also offers a second version called Aero Glass which provides even more
graphics intensive features but requires a 3D video card that supports DirectX 9, and it must have a
Longhorn display driver model (LDDM) driver. The Aero interface introduces translucent title bars,
rounded edges, and stylish color schemes, amongst other features. Many older video cards that ran
Windows XP are unable to display Vista with the AeroGlass feature.
Bitlocker
Windows BitLocker Drive Encryption is a security feature that provides data protection for your computer
by encrypting all data stored on the Windows operating system volume. In Windows, a volume consists
of one or more partitions on one or more hard disks. BitLocker works with simple volumes, where one
volume (disk) is one partition. A volume usually has a drive letter assigned, such as "C."
Bitlocker works together with a device in your computer called a Trusted Platform Module (TPM), which
is a microchip that is built into a computer. It is used to store cryptographic information, such as
encryption keys. Information stored on the TPM can be more secure from external software attacks and
physical theft.
BitLocker uses the TPM to help protect the Windows operating system and user data and helps to
ensure that a computer is not tampered with, even if it is left unattended, lost, or stolen.
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BitLocker can also be used without a TPM. To use BitLocker on a computer without a TPM, you must
change the default behavior of the BitLocker setup wizard by using a networking Group Policy, or you
must configure BitLocker by using a script. When BitLocker is used without a TPM, the required
encryption keys are stored on a USB flash drive that must be presented to unlock the data stored on a
volume.
Bootrec
The BOOTREC command will help you when your operating system has trouble booting and Startup
Repair can't fix the problem. BOOTREC is run from the DOS Command Prompt box, or if you launch
Windows in Safe Mode – Command Prompt mode.
There are four parameters available: /FixMbr, /FixBoot, /ScanOs and /RebuildBcd.




The FixMBR allows the repair of a corrupted or damaged Master Boot Record (MBR). The Master
Boot Record is the first sector of your drive and its purpose is to tell the BIOS where to look for
the operating system on your computer. Usually, you will use this parameter when you meet one
of these error messages: “Operating System not found", “Error loading operating system",
“Missing operating system" or “Invalid partition table".
The FixBoot option writes a new boot sector to the system partition. The tool will use a boot
sector that is compatible with your Windows version, whether it's Windows 7, 8 or 8.1. Using this
parameter is useful when the boot sector has been replaced with a non-standard Windows Vista,
7, 8 or 8.1 boot sector, or if the boot sector is damaged, or if an earlier Windows operating
system has been installed after your version of Windows was installed.
The ScanOs option will help you if your computer has multiple operating systems installed but not
all of them are available. Using the /ScanOS option with BOOTREC will launch a scan on all
disks for any Windows Vista, 7, 8 or 8.1 installations that are not currently included in the Boot
Configuration Data (BCD).
The RebuildBcd option will fix some errors by completely rebuilding the BCD. The Boot
Configuration Data (BCD) contains a detailed list of what is supposed to load at startup. Microsoft
indicates that a boot error can also be caused by missing or damaged files in the BCD.
Category view vs. classic view
In the Windows Control Panel, a change was made starting with Windows XP to display specific tasks in
what is called “category view.” In previous versions, a number of Control Panel icons would appear to
allow the user to change various aspects of Windows (such as the Display, Sound, Mouse, and so forth).
Some people like category view, while others prefer to see the individual Control Panel icons. You can
change the Control Panel to display information either in Category or Classic View, depending on your
personal preference.
Compatibility mode and virtual XP mode
Compatibility mode is a method whereby a software application either emulates an older version of
software, or mimics another operating system. It does this in order to allow obsolete or incompatible
software or files to remain compatible with the computer's newer hardware or software. Examples of the
software using the mode are operating systems and Internet Explorer.
Using Windows XP Mode, you can run programs that were designed for Windows XP on computers
running Windows 7 Professional, Enterprise, or Ultimate editions. However, Windows XP Mode is not
supported on Windows 8.
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Windows XP Mode works in two ways—both as a virtual operating system and as a way to open
programs within Windows 7. It runs in a separate window on the Windows 7 desktop, much like a
program, except it's a fully-functional, fully-licensed version of Windows XP. In Windows XP Mode, you
can access your physical computer's CD/DVD drive, install programs, save files, and perform other tasks
as if you were using a computer running Windows XP.
When you install a program in Windows XP Mode, the program appears in both the Windows XP Mode
list of programs and in the Windows 7 list of programs, so you can open the program directly from
Windows 7.
Control Panel
The Windows Control Panel allows the user to configure various aspects of the operating system, add
new hardware to the system, and add and/or remove software from your system. For example: the
Display icon lets you change your video driver and screen configuration. The Keyboard and Mouse icons
let you control the operation of these devices. The Network icon allows you to add and configure
networking hardware and software so that you can interact with local area networks and dial up
connections. The Sounds icon allows you to associate certain system events (like the system start and
shutdown) with sound files, so that the sound will play when that event occurs. The Users icon allows you
to add or delete user accounts, and have customized configurations for different users of the same
computer. The System icon lets you see a summary of the recognized system components, and through
the Device Manager, it lets you add or remove components from your system configuration.
DirectX diagnostic tool (DXDIAG.EXE)
You can diagnose and resolve DirectX video display problems using the DirectX Diagnostic Tool and the
Multimedia and Games Troubleshooter. The DirectX Diagnostic Tool helps you test the functionality of
DirectX, to diagnose problems, and to adjust the level of hardware support used by DirectX, which can be
used to avoid issues on some multimedia drives. The DirectX Diagnostic Tool (Dxdiag.exe) is installed
with DirectX and can be run by clicking Start, clicking Run, and then typing dxdiag and clicking OK.
For information about using the DirectX Diagnostic tool, click the Help button within the DirectX
Diagnostic application.
Disk Management
Disk Management is a graphical tool for managing disks. This tool encompasses and extends the
functionality of character-based disk management tools (such as the old MS-DOS FDISK utility). It is
found within the Microsoft Management Console which is discussed later in this chapter.
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The following list provides an overview of some of the things you can do with this graphical tool:










Create and delete partitions on a hard disk and logical drives within an extended partition.
Add and mount drive arrays as well as single disks.
Format and label volumes.
Extend, split or shrink existing disk partitions.
Read status information about disks such as the partition sizes and the amount of free space that
is available for creating additional partitions.
Read status information about Windows NTFS and FAT16/32 volumes such as the drive-letter
assignment, volume label, file system type, and size.
Make and change drive-letter assignments for hard disk volumes as well as CD-ROM devices.
Create and delete volume sets.
Extend volumes and volume sets.
Create and delete stripe sets.
Partitioning the internal hard disk on a new computer is done during initial setup when you load the
Windows operating software. Making changes to that disk or partitioning an additional new hard disk is
done using Disk Management.
Disk Management cannot be used to further partition the system partition because it contains files
required to operate Windows itself.
Diskpart
DISKPART is a text-mode command interpreter that enables you to manage objects (disks, partitions, or
volumes) by using scripts or direct input from a command prompt. Before you can use DiskPart
commands on a disk, partition, or volume, you must first list and then select the object to give it focus.
When an object has focus, any DiskPart commands that you type act on that object.
You can list the available objects and determine an object's number or drive letter by using the list disk,
list volume, and list partition commands. The list disk and list volume commands display all disks and
volumes on the computer. However, the list partition command only displays partitions on the disk that
has focus. When you use the list commands, an asterisk (*) appears next to the object with focus. You
select an object by its number or drive letter, such as disk 0, partition 1, volume 3, or volume C.
When you select an object, the focus remains on that object until you select a different object. For
example, if the focus is set on disk 0, and you select volume 8 on disk 2, the focus shifts from disk 0 to
disk 2, volume 8. Some commands automatically change the focus. For example, when you create a
new partition, the focus automatically switches to the new partition.
You can only give focus to a partition on the selected disk. When a partition has focus, the related
volume (if any) also has focus. When a volume has focus, the related disk and partition also have focus if
the volume maps to a single specific partition. If this is not the case, then focus on the disk and partition
is lost.
Event Viewer
Event Viewer is the tool you can use to monitor events in your system. You can use Event Viewer to view
and manage System, Security, and Application event logs. You can also archive event logs. The
event-logging service starts automatically when you run Windows. You can stop event logging with the
Services tool in Control Panel.
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Expand
The EXPAND command expands one or more compressed update files. Expand supports opening
updates for Windows 8.1 as well as previous versions of Windows. By using Expand, you can open and
examine updates for various Windows operating systems.
Gadgets and sidebars
Windows Sidebar is a pane on the side of the Windows Vista (or Windows 7) desktop that organizes
gadgets (small applications with a wide variety of possible uses) and makes them easy to access.
Sidebar gadgets include a clock, an RSS (Really Simple Syndication) reader for getting news updates, a
weather update gadget, and so forth.
Gadgets may be nice, but they do take up system resources that can be used for other applications. In
fact, Microsoft in 2012 ended support for the use of gadgets in Windows, because they were a potential
gateway for malicious software to attack your PC.
GPUPDATE and GPRESULT
The GPUPDATE command refreshes local and Active Directory-based Group Policy settings, including
security settings. This command supersedes the now obsolete /refreshpolicy option for the secedit
command.
The GPRESULT command displays the Resultant Set of Policy (RSoP) information for a remote user
and computer. In other words, GPRESULT shows what policies have been applied to the computer and
user, and if certain security policies will supercede other policies that have been applied.
To use RSoP reporting for remotely targeted computers through the firewall, you must have firewall rules
established that enable inbound network traffic on the ports.
These commands are issued from the DOS Command Prompt box.
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IPCONFIG (/all /release /renew)
IPCONFIG is a command line tool used to control the network connections on Windows NT through
Windows 10 operating systems. Typing IPCONFIG and pressing Enter at the command prompt will
display your current IP network settings, including your IP address, your subnet mask, your default
network gateway, and your connection-specific DNS suffix for all of your network adapters.
There are three main command options that provide additional information or functions for IPCONFIG:
/all, /release, and /renew. The /all option shows all IP related information for your network connections,
more than just with the plain IPCONFIG command. The /release option drops your DHCP-obtained IP
address, and the /renew option obtains an fresh IP address from the DHCP server.
Local Users and Groups
Local Users and Groups is a tool you can use to manage account security for a computer running
Windows. With this application you can:



Create and manage user accounts,
Create and manage groups, and
Manage the security policies.
The application window displays two lists: The upper list of user accounts and the lower list of groups.
One or more user accounts (or one group) can be selected and then managed using commands on the
User menu.
Microsoft Management Console (MMC)
In Windows, the Microsoft Management Console (MMC) is a single consolidated utility that lets you
manage user accounts through the User Manager, configure devices through the Device Manager,
manage and format disks through the Disk Management option (known in Windows NT as Disk
Administrator), and manage the current set of running services. The MMC application brings all of the
major system management utilities together into one screen.
To access the MMC, right-click on My Computer, and then select the Manage option.
MSCONFIG
The System Configuration utility (MSCONFIG) automates the routine troubleshooting steps that
Microsoft Customer Support Services professionals use when they diagnose system configuration
issues. When you use this utility to modify the system configuration, you can select check boxes to
eliminate issues that do not apply to your configuration. This process reduces the risk of typing errors that
you may make when you use any text editor, such as Notepad. You must be logged on as an
administrator or as a member of the Administrators group to use the System Configuration utility.
When you use the System Configuration utility, you can easily reset or change the configuration settings
in Windows to include preferences for the following files and settings:





The System.ini file
The Win.ini file
The Boot.ini file
Programs that are set to load during the startup process (these programs are specified in the
Startup folder and in the Registry)
Environment settings and international settings
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MSINFO32
This command will provide the user with a summary of the computer’s hardware resources, computer
components, software environment variables and drivers, Internet settings, and Microsoft Office
application settings. This will give you a way to quickly evaluate the computer system, operating system
variables, and Office application suite settings.
To run MSINFO32, click on the Start button, then select Run, and in the Run box enter the following
command:
MSINFO32 [Enter]
MSTSC
The MSTSC command creates connections to Remote Desktop Session Host (RD Session Host)
servers or other remote computers, edits an existing Remote Desktop Connection (.rdp) configuration
file, and migrates legacy connection files that were created with Client Connection Manager to new .rdp
connection files.
My Computer
The "My Computer" icon allows the user to run a variant of Windows Explorer. Double-clicking on My
Computer icon will allow you to see all of the available disk drives, the Printers folder where your
configured printers are listed, the Windows Control Panel, and the Dial-up Networking folder where your
dial-up connections are located. Double-clicking on the drive icons lets you browse through the folders
and files on each drive, allowing you to copy, cut, paste, move and delete both files and directories. The
Add Printer Wizard is contained in the Printers folder. It allows you to add a printer quickly and easily.
The Add New Connection Wizard in the Dial Up Networking folder allows you to create new dial up
connection icons.
NET
NET is a prefix to a series of DOS-level commands that let you access, connect to, print, configure and
view networking resources on a Microsoft network. For example: the command NET USE H:= [some
server name and disk directory] will give you a networked H: drive on your PC. NET PRINT will let you
print a file to a networked printer, and so forth. Typing NET /? at the DOS prompt will show you all of the
available sub-commands for the NET command. The key sub-commands are:
ACCOUNTS, COMPUTER, CONFIG, CONTINUE, FILE, GROUP, HELP, HELPMSG, LOCALGROUP,
NAME, PAUSE, PRINT, SEND, SESSION, SHARE, START, STATISTICS, STOP, TIME, USE, USER,
and VIEW.
NETDOM
The NETDOM command-line tool in Windows Server versions allows the used join a computer to a
networking domain, manage computer accounts for domain workstations, establish and manage trust
relationships between workstations and domains, and verify/reset secure channels between
workstations and servers. You must run NETDOM from an elevated (administrative) command prompt.
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NSLOOKUP
Displays information that you can use to diagnose Domain Name System (DNS) infrastructure. Before
using this tool, you should be familiar with how DNS works. The NSLOOKUP command-line tool is
available all computers that have the TCP/IP protocol installed. If you typed at the command prompt –
NSLOOKUP www.pgcc.edu [Enter]
the utility would give you the IP address associated with that web server. You also could enter an IP
address with NSLOOKUP, and it will give you the domain name associated with that address.
Performance Monitor
Performance Monitor is a graphical tool for measuring the performance of your own computer or other
computers on a network. On each computer, you can view the behavior of objects, such as processors,
memory, cache, threads, and processes.
Each of these objects has an associated set of counters that provide information about device usage,
queue lengths, delays, and information used to measure throughput and internal congestion.
It provides charting, alerting, and reporting capabilities that reflect both current activity and ongoing
logging. You can open, browse, and chart log files later as if they reflected current activity.
The following overview lists how you use Performance Monitor to view the performance of objects:









Simultaneously view data from any number of computers.
View and dynamically change charts reflecting current activity and showing counter values that
are updated at a user-defined frequency.
Export data from charts, logs, alert logs, and reports to spreadsheet or database programs for
further manipulation and printing.
Add system alerts that list events in the Alert Log and notify you either by reverting to Alert view,
logging the event in Event Viewer's Application log, or issuing a network alert.
Run a predefined program either every time or only the first time a counter value goes over or
under a user-defined value.
Create log files containing data about objects on different computers.
Append selected sections of existing log files to a single file, forming a long-term archive.
View current-activity reports or create reports from existing log files.
Save individual chart, alert, log, and report settings, or save the entire workspace setup to reuse
when needed.
Ping
Ping is a utility that determines whether a specific IP address is accessible. It works by sending a packet
to the specified IP address and waiting for a reply. PING is used primarily to troubleshoot Internet
connections. Although there are many freeware and shareware Ping utilities available for personal
computers, the Microsoft-supplied Ping utility works just fine.
Pinning
In Windows, you can take an icon for a commonly-used application and “pin it” to the Taskbar or Start
menu, so that it is easily available for use. Right-clicking on an application in the Start menu and
selecting “Pin to Taskbar” will place an identical icon into the Taskbar. You can also do the reverse, and
pin an icon in the taskbar into the Start menu.
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ReadyBoost
ReadyBoost is a disk caching software component developed by Microsoft for Windows Vista and
included in later versions of the Windows operating system.
ReadyBoost enables certain kinds of memory mass storage devices, including CompactFlash, SD cards,
and USB flash drives, to be used as a write cache between a hard drive and random access memory in
an effort to increase computing performance. ReadyBoost relies on the SuperFetch technology and, like
SuperFetch, adjusts its cache based on user activity. Other features, including ReadyDrive are
implemented in a manner similar to ReadyBoost.
REGEDIT and REGEDT32
Windows comes with a Registry editing tool that can help you to repair or edit a faulty registry. The
program is called REGEDIT.EXE. It is a fairly simple database editor, and it lets you search the Registry
for specific text strings (by pressing Ctrl - F). For example: if Windows gives you error messages that
certain .DLL files could not be found on your PC, you can use REGEDIT to go into the Registry and delete
out all mentions of that now-missing virtual device driver (VxD) file, thereby eliminating the error
messages at system boot-up time.
Another Windows Registry editor, REGEDT32.EXE, is available In Windows XP and Vista to modify the
Registry manually. It displays the Registry hives as a series of folders. You can use either registry editor,
but Microsoft (and the author) recommend using REGEDIT.EXE.
Robocopy
The ROBOCOPY command, short for "Robust File Copy", is a command-line directory and/or file
replication command. Robocopy functionally replaces the XCOPY command, and it provides more
options than XCOPY did. It has been available as part of the Windows Resource Kit starting with
Windows NT 4.0, and was first introduced as a standard feature in Windows Vista and Windows Server
2008.
The RUN command
The RUN command lets you launch programs that are not listed on the Start menu, nor is there an icon on
the Windows desktop for a given program.
By clicking on Start, then selecting Run, and then typing in the name (preferably the directory location and
the name) of the program, you can launch any program that is available to Windows. For example:
clicking on Start, then clicking on Run, and then typing MSCONFIG into the dialog box and clicking OK
will launch the Windows System Configuration Editor.
Shadow copy
Shadow Copy (also known as Volume Snapshot Service, Volume Shadow Copy Service or VSS) is a
technology included in Microsoft Windows that allows taking manual or automatic backup copies or
snapshots of computer files or volumes, even when they are in use. It is implemented as a Windows
service called the Volume Shadow Copy service. A software VSS provider service is also included as
part of Windows to be used by Windows applications.
Shadow Copy technology requires the file system to be NTFS in order to create and store shadow
copies. Shadow Copies can be created on local and external (removable or network) volumes by any
Windows component that uses this technology, such as when creating a scheduled Windows Backup or
automatic System Restore point.
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System File Checker (SFC)
System File Checker scans and verifies the versions of all protected system files after you restart your
computer. This process will reinstall known-good versions of all Windows system files over any files that
have been damaged, corrupted, or are incompatible versions from an earlier release of Windows.
To run SFC, click on the Start button, then select Run, and in the Run box enter the following command:
SFC /scannow [Enter]
You will need to have a copy of your Windows installation CD (or DVD) in your optical drive when SFC is
running; the application will read the known-good files from the CD and copy them over any invalid
system files on your hard disk. The PC will reboot when SFC is completed.
System Restore
System Restore is a feature in Microsoft Windows that allows the user to revert their computer's state
(including system files, installed applications, Windows Registry, and system settings) to that of a
previous point in time, which can be used to recover from system malfunctions or other problems. First
included in Windows ME, it has since been included in all following desktop versions of Windows
released since, excluding the Windows Server.
Note that in Windows 10, System Restore is turned off by default and must be enabled by users in order
to function.
In prior Windows versions, System Restore was based on a file filter that watched changes for a certain
set of file extensions, and then copied files before they were overwritten. An updated version of System
Restore introduced by Windows Vista uses the Shadow Copy service as a backend (allowing block-level
changes in files located in any directory on the volume to be monitored and backed up regardless of their
location) and allows System Restore to be used from the Windows Recovery Environment in case the
Windows installation no longer boots at all.
Instructions on how to run System restore are found later in this chapter, when we will discuss the
Windows Registry.
TASKKILL and TASKLIST
The TASKKILL command ends one or more tasks or processes currently running on the computer.
Processes can be killed either by process ID or image name. this process ID or image name can be
viewed from the Windows Task Manager screen, or by using the TASKLIST command.
The TASKLIST command displays a list of applications and services with their Process ID (PID) for all
tasks running on either a local or a remote computer.
These commands are issued from the DOS Command Prompt box.
TRACERT
Tracert is a utility that traces a packet from your computer to an Internet host, showing how many hops
the packet requires to reach the host and how long each hop takes. If you're visiting a Web site and pages
are appearing slowly, you can use tracert to figure out where the longest delays are occurring.
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The original traceroute is a UNIX utility, but nearly all platforms have something similar. Windows
includes a traceroute utility called tracert. In Windows, you can run tracert by selecting Start->Run, and
then entering tracert followed by the domain name of the host. For example:
tracert academic.pgcc.edu
Tracert utilities work by sending packets with low time-to-live (TTL) fields. The TTL value specifies how
many hops the packet is allowed before it is returned. When a packet can't reach its destination because
the TTL value is too low, the last host returns the packet and identifies itself.
By sending a series of packets and incrementing the TTL value with each successive packet, tracert finds
out who all the intermediary hosts are.
User Account Control (UAC)
Starting with Windows Vista, User Account Control is a feature that was designed to prevent
unauthorized changes to your computer. When functions that could potentially affect your computer's
operation are made, UAC will prompt for permission or an administrator's password before continuing
with the task. There are four different alert messages associated with User Account Control:
●
●
●
●
Windows needs your permission to continue
A program needs your permission to continue
An unidentified program wants access to your computer
This program has been blocked
UAC can be disabled by the user by going to the User Accounts Control Panel applet, and un-checking
the box that enables UAC. In Windows 7 and above, the applet gives a slider-style control to turn UAC
security checking up, or down, or off. UAC was perhaps the single feature that turned people away from
Windows Vista when it was introduced.
Windows Backup
Windows Backup is a graphical tool for protecting data from accidental loss or hardware and media
failures. Backup makes it easy for you to use a tape drive or other media types to back up and restore
your important files on either the Windows file system (NTFS) or file allocation table (FAT) file system.
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The following list provides an overview of some of the things you can do with this graphical tool to protect
your data:










Backup and restore both local and remote files on NTFS or FAT volumes from your own computer
using an attached tape drive.
Select files for backing up or restoring by volume, directory, or individual filename, and view
detailed file information, such as size or modification date.
Select an optional verification pass to ensure reliable backups or restorations.
Perform any of the following common backup operations: Normal, Copy, Incremental, Differential,
and Daily Copy.
Place multiple backup sets on a tape, and either append new backup sets or overwrite the whole
tape with the new ones.
Span multiple tapes with both backup sets and files, since there is no file-size restriction.
Create a batch file to automate repeated backups of drives.
Review a full catalog of backup sets and individual file and directory information so you can select
files to be restored.
Control the destination drive and directory for a restore operation, and receive appropriate options
for action you can take when a restore would overwrite a more recent file.
Save log information on tape operations to a file. Also view tape-operation information in the
Windows Event Viewer.
Windows Defender
Windows Defender is a software product that attempts to detect and remove malware. Initially released
as an antispyware program, it was first released as a free download for Windows XP, shipped with
Windows Vista and by default, and currently ships with antivirus capabilities as part of Windows 10.
Other well-known anti-malware programs include MalwareBytes, and Spybot Search-and-Destroy.
Windows Easy Transfer
Windows Easy Transfer (WET) is a specialized file transfer program developed by Microsoft which
allows users of the Windows operating system to transfer personal files and settings from a computer
running an earlier version of Windows to a computer running a newer version.
Windows Easy Transfer was introduced in Windows Vista and is included in the Windows 7, Windows 8,
and Windows 8.1 operating systems. It replaces the Files and Settings Transfer Wizard included with
Windows XP and offers limited migration services for computers running Windows 2000 Service Pack 4
and Windows XP Service Pack 2.
WET does not transfer applications; it transfers files and most settings. If you transfer files containing
malicious software from your old computer, that software can be transferred to your new computer. You
should run antivirus and spyware protection programs at all times, especially on your old computer,
before you select files to transfer. Once you have transferred files to your new computer, the customer
should run those programs on the new computer to make sure that no malicious software was
transferred.
The Windows Easy Transfer program was discontinued in Windows 10. Microsoft has chosen to provide
a free version of Laplink's PCmover Express as an alternative to WET. A paid alternative is Zinstall Easy
Transfer; Zinstall also allows customers to transfer programs, in addition to files.
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Windows Explorer
Explorer is the one program that is at the heart of the operating system. It is the “shell program” that
provides the familiar interface that all of us have become accustomed to using. Explorer lets you browse
through all of the available drives and directories, allowing you to copy, cut, paste, move and delete files
and directories.
Explorer is one of the core programs that makes Windows operate. The desktop appears because
Explorer is running. When you double-click on My Computer, another view of Explorer opens. When you
right-click on My Computer and select the Explore option, yet another view of Explorer appears. Every
application on your PC operates in conjunction with Explorer.
Windows Firewall
Windows Firewall is a software component of Microsoft Windows that provides firewalling and packet
filtering functions. It was first included in Windows XP and Windows Server 2003. Prior to the release of
Windows XP Service Pack 2 in 2004, it was known as Internet Connection Firewall.
When Windows Firewall is enabled, one of three profiles is activated automatically for each network
interface:



Public assumes that the network is shared with the World and is the most restrictive profile.
Private assumes that the network is isolated from the Internet and allows more inbound
connections than public. A network is never assumed to be private unless designated as such by
a local administrator.
Domain profile is the least restrictive. It allows more inbound connections to allow for file sharing
etc. The domain profile is selected automatically when connected to a network with a domain
trusted by the local computer.
Security log capabilities are included, which can record IP addresses and other data relating to
connections originating from the home or office network or the Internet. It can record both dropped
packets and successful connections. This can be used, for instance, to track every time a computer on
the network connects to a website
Windows Security Center
Windows Security Center (WSC) is a monitoring component of the Windows family of operating systems.
It monitors the security and maintenance status of the computer. Its monitoring criteria includes optimal
operation of personal firewalls, anti-virus software and anti-spyware software, as well as the working
status of Network Access Protection, Windows Update, User Account Control, Windows Error Reporting
and Backup and Restore. It notifies the user of any problem with the monitored criteria, e.g. when an
antivirus program is not up-to-date or is offline.
WSC in Windows Vista monitors issues such as anti-spyware software, User Account Control, and
Internet Explorer security settings. It can also display logos of third-party products that have been
registered with the Security Center.
In Windows 7, Windows Security Center was renamed to Action Center. It was designed to centralize
and reduce the number of notifications about the system. As such, it encompasses both security and
maintenance of the computer. The notification icon on Windows Taskbar only appears when there is a
message for review, and it replaces five separate notification icons found in Windows Vista.
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In Windows 8, Action Center monitors 10 new items: Microsoft account, Windows activation,
SmartScreen, automatic maintenance, drive status, device software, startup apps, HomeGroup, File
History, and Storage Spaces.
In Windows 10, the Action Center has been renamed to Security and Maintenance. Despite the change
of name, the functionality has not changed from what the Action Center provided in Windows 8.
Changes Made to Windows Versions 8 and 8.1
Charm Bar
The Windows 8 charm bar is the primary toolbar in Windows 8, which can be accessed from the desktop
view of Windows 8 or the Windows 8 start screen, as well as any app that you use in Windows 8.
You can get to the charm bar on a PC by either dragging your mouse to the to the top or bottom right
corners of the screen, and the charm bar will pop up on the right side of the screen. Moving the mouse
away will hide the charm bar, and also the Charm Bar will close after 3 seconds of inactivity.
You can also bring up the charm bar by pressing the Windows key+C, however, and when you do this, in
addition to seeing the charm bar, you’ll also see the date and time in the bottom left corner, and this will
keep the Charm Bar open.
Metro User Interface
Starting with Windows Phone 7, Microsoft introduced its Metro style user interface (UI). The Metro style
UI is the touch-and-tile interface that Microsoft designed to create an interface focused on content,
information, and movement. It was designed to embrace five principles: clean, light, fast, open
aesthetics; dynamic, moving transitions and interactions; embrace the beauty of typography; contentfocused interface; and authentically digital design.
The user interface for Windows 8 is the same Metro style UI. The Metro style works with tablet and
touch-screen devices. Windows 8 features such as user log in with tap and trace gestures, and
accessing the charms menu with a swipe are just a couple of the ways in which Microsoft uses the Metro
UI to work well with new hardware as well as hardware users already own.
Although Microsoft performed a great deal of focus group testing of the Metro interface and believed it
would be quickly accepted by users, Windows 8 (and 8.1) was roundly rejected by customers. Windows
10 was rolled out to the public as a replacement for Windows 8, and was provided to all Windows 7 and
8 consumers for free, to make amends for this marketing blunder. In fact, in February 2016, support for
the Windows Phone (and the Metro interface it used) was discontinued by Microsoft.
Multi-monitor task bars
The Taskbar in Windows 8 (and Windows 10) allows you to span multiple monitors (unlike in Windows
Vista or 7), and can be customized so that the taskbar buttons on each monitor are the buttons for
windows open on that monitor. You can also make both taskbars show all windows if you choose.
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OneDrive
OneDrive (previously called SkyDrive, Windows Live SkyDrive and Windows Live Folders) is a file
hosting service that allows users to sync files and later access them from a web browser or mobile
device. Users can share files publicly or with their contacts; publicly shared files do not require a
Microsoft account to access. It is part of the suite of online services formerly known as Windows Live.
The current storage limit for OneDrive users is 1 TB for Office 365 paid subscribers or 5 GB of free
storage.
Side-by-side apps
On tablet devices, you can run in split-screen mode to run two separate applications. This is similar to
running several applications on a PC, as PCs are designed to multi-task several applications at a time.
In Windows 8, you also can run a “Metro app” and a regular desktop application in side-by-side mode.
Start Screen
In Windows 8 and 8.1, instead of having a “Start button” to launch an application, the “Start screen”
appeared, with various tiles that would let you launch commonly-used applications. A very rudimentary
Start menu was available, but it was essentially hidden from view. This was a part of the Metro user
interface design in Windows 8.
Users roundly rejected the concept of a Start screen; as such Windows 10 re-introduced a Start menu,
with the option of using a Start screen as a secondary method to launch an application.
Windows Live sign in
Starting with Windows 8, users were prompted to create a Windows Live account when the operating
system was finished installing. This would provide a password for the computer, and also would allow
access to online Microsoft resources such as OneDrive, Outlook email, Office365, and so forth.
Windows store
The Windows Store is located online, and it provides a large variety of applications that can be used on
an xBox, Windows Phone, Windows Surface tablet, or computers running Windows. It is comparable to
the Apple iTunes store or the Google Play store online.
NOTES
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An overview of The Windows Registry
The Windows Registry provides a single, unified database for storing system and application
configuration data in a hierarchical form. Because the Registry contains all the settings required to
configure memory, hardware peripherals, and Windows-supplied network components, you may find that
it is no longer necessary to configure settings in startup configuration files and initialization (.INI) files, as
was used in earlier versions of Windows.
Because settings are stored in a central location, you can provide both local and remote support for
system configuration using Windows-based tools.
The Registry is similar to the INI files used under previous versions of Windows, with each key in the
Registry similar to a bracketed heading in an INI file and with Registry values similar to entries under the
INI headings. However, Registry keys can contain sub-keys, while INI files do not support nested
headings. Registry values can also consist of binary data, rather than the simple strings used in INI files.
Although Microsoft discourages using INI files in favor of Registry entries, some applications (particularly
older 16-bit Windows-based applications) still use INI files. Windows supports INI files solely for
compatibility with those applications and related tools (such as setup programs).
The Registry provides the following benefits in Windows:
A single source provides data for enumerating and configuring the hardware, applications, device drivers,
and operating system control parameters. The configuration information can be recovered easily in the
event of system failure.
Users and administrators can configure computer options by using standard Control Panel tools and
other administrative tools, reducing the likelihood of syntactic errors in configuration information.
A set of network-independent functions can be used to set and query configuration information, allowing
system administrators to examine configuration data on remote networked computers. The operating
system automatically backs up the last good configuration used to start the computer.
Because user-specific Registry information can be maintained on a central network server when user
profiles are enabled, users can have access to personal desktop and network access preferences when
logging on to any computer, and settings for multiple users can be maintained on a single computer.
Also, system policies (called Group Policy Objects or GPOs) can be used to enforce certain Registry
settings for individuals, workgroups, or all users.
Main Registry components
There are several classes (or hives) of registries within the single Windows Registry. Each class deals
with a specific aspect of how Windows associates files with applications, and configuration settings with
users and hardware. Listed below are the major hive classes within the Windows Registry:
HKEY_CLASSES_ROOT,
HKEY_CURRENT_USER,
and HKEY_CURRENT_CONFIG.
HKEY_LOCAL_MACHINE,
HKEY_USERS,
The registry hive called HKEY_DYN_DATA exists only in Windows 95, 98 and ME.
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What functions do these parts of the Registry perform?
HKEY_CLASSES_ROOT
This part of the Registry provides Windows with the information it needs to associate different types of
files with the applications for which they belong. Files in a DOS/Windows environment have a file
extension, usually 3 characters in length, that let the operating system associate the file to an application
with which it is opened.
For example, .DLL files are called and used by application software, or can be downloaded from the
Internet; .AVI files are video files that the Windows Media Player (MPLAYER.EXE) will display for you. If
you double click on the icon for an .AVI file, MPLAYER would load automatically and play the file,
because the Registry associates that file with that application.
HKEY_CURRENT_USER
This part of the Registry provides Windows with the "personal" desktop configuration information needed
for the currently logged-in user of Windows. Windows gives you the ability to have multiple configurations
of the same installation of Windows for different users of the same machine, so each person's desktop
will be configured to their liking. This includes desktop schemes, sounds, colors, icons, keyboard layout,
networking configuration, and available software.
HKEY_LOCAL_MACHINE
This part of the Registry provides Windows with the non-user-specific, hardware based aspects of the
host (or current) computer. For example, the HARDWARE branch of this sub-tree is where Windows
stores all of the information about Plug-and-Play based hardware in your computer. Your network
hardware configuration, hardware requirements of application software, audio and video controls, drive
controller and video card configuration, and your PCI bus configuration information is all included in this
part of the Registry.
HKEY_USERS
This part of the Registry provides Windows with the list and configuration information for all registered
users of Windows on that PC. In this instance, registered means anyone who has logged into the PC
(NOT necessarily onto the network) and has done anything under the desktop interface. The same kinds
of information found in HKEY_CURRENT_USER will be found for all recognized users under the
HKEY_USERS subtree.
HKEY_CURRENT_CONFIG
This part of the Registry provides Windows with the current machine's hardware and Plug-and-Play
configuration. This is set (or reconfigured) through the use of .INF (information) files used when Windows
installs new devices into the PC. The Windows configuration manager is primarily responsible for
controlling this aspect of the Registry, working together with the Plug-and-Play BIOS, the device drivers
and VxDs (virtual device drivers), the software enumerators that poll each Plug-and-Play device, any
resource arbitrators on the system board, and the application programming interfaces (APIs) that allow
software to interface with the hardware.
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HKEY_DYN_DATA [ Exists ONLY in Windows 95, 98 and ME ]
This part of the Registry provides Windows with the information it needs to use dynamic (virtual) device
drivers, or VxDs. Dynamic drivers are loaded only when an application calls to a specific resource on your
PC (modem, sound card. etc.); these drivers may not necessarily be loaded when Windows boots up.
The VXDLDR module of Windows handles the loading of VxDs when needed by the operating system
and/or the specific device. Also, this part of the Registry keeps track of information on the kernel of
Windows that has been loaded into RAM, the Virtual FAT that has been loaded into RAM, and the Virtual
Memory Manager module of Windows.
Restoring the Registry files in Windows 2000 and Windows XP / Vista / Windows 7
This section describes how to back up, edit, and restore the registry. Microsoft recommends that before
you edit the registry, you back up the registry and understand how to restore it if a problem occurs.
How to back up the Windows 2000 Registry
Before you edit the registry, export the keys in the registry that you plan to edit, or back up the whole
registry. If a problem occurs, you can then follow the steps shown below to restore the registry to its
previous state.
Exporting Registry keys
You can follow these steps to export a registry key before you edit it:
NOTE: Do not follow these steps to export a whole registry hive (for example, HKEY_CURRENT_USER).
If you must back up whole registry hives, back up the whole registry instead.
●
●
●
●
●
Click Start, and then click Run.
In the Open box, type regedt32, and then click OK.
Locate and then click the key that contains the values that you want to edit.
On the Registry menu, click Save Key.
In the Save inbox, select a location in which to save the .reg file, type a file name in the File name
box, and then click Save.
How to back up the entire Windows Registry
Follow these steps to export the entire Registry to a .REG file:
●
●
●
●
●
Click Start, and then click Run.
In the Open box, type regedit, and then click OK.
Make sure that My Computer is highlighted in the Registry editor.
Click on the File drop-down menu, and click the Export option.
In the Save inbox, select a location in which to save the .reg file, type a file name in the File name
box, and then click Save.
Note: this technique works in all Windows versions.
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To back up the whole registry, you also can use the Microsoft Backup utility to create an Emergency
Repair Disk (ERD), or back up the System State (which includes the registry, the COM+ Class
Registration database, and your boot files).
For additional information about using the Backup utility to create an ERD, click the following article
number to view the article in the Microsoft Knowledge Base: 231777
(http://support.microsoft.com/kb/231777/ ) How to create an emergency repair disk in Windows 2000
For additional information about using the Backup utility to back up the system state, click the following
article number to view the article in the Microsoft Knowledge Base: 240363
(http://support.microsoft.com/kb/240363/ ) How to use the Backup program to back up and restore the
system state in Windows 2000
How to back up the Windows XP / Vista / Windows 7 Registry
●
●
●
●
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●
Use the System Restore utility from the Start menu. Click on Start, then click on Programs (or All
Programs) / Accessories/ System Tools, and select System Restore.
(You also can click on Start, then Run, and type %SystemRoot%\system32\restore\rstrui.exe,
and then click OK.)
On the Welcome to System Restore page, click Create a restore point, and then click Next .
On the Create a Restore Point page, type a name for the restore point and then click Create
After the restore point has been created, click Close.
Note: If System Restore is turned off, you will receive a message that asks whether you want to
turn on System Restore now. Click Yes. Then, in the System Properties dialog box, click to clear
the Turn off System Restore check box, click OK, and then repeat this step.
How To Restore the Windows XP / Vista / Windows 7 Registry
●
●
●
●
●
●
●
You also can use System Restore to undo registry changes in Windows XP, Windows Vista or
Windows 7
Click on Start, then click on Programs (or All Programs) / Accessories/ System Tools, and select
System Restore.
(You also can click on Start, then Run, and type %SystemRoot%\System32\Restore\Rstrui.exe,
and then click OK.)
On the Welcome to System Restore page, click Restore my computer to an earlier time (if it is not
already selected), and then click Next .
On the Select a Restore Point page, click the system checkpoint. In the On this list select the
restore point area, click an entry that is named "Guided Help (Registry Backup)," and then click
Next. If a System Restore message appears that lists configuration changes that System Restore
will make, click OK.
On the Confirm Restore Point Selection page, click Next. System Restore restores the previous
Windows configuration and then restarts the computer.
Log on to the computer. When the System Restore confirmation page appears, click OK.
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Using Regedit to edit your Registry
Windows comes with a Registry editing tool that can help you to repair or edit a faulty registry. The
program is called REGEDIT.EXE. It is a fairly simple database editor, and it lets you search the Registry
for specific text strings (by pressing Ctrl - F).
For example: if Windows gives you error messages that certain .DLL files could not be found on your PC,
you can use REGEDIT to go into the Registry and delete out all mentions of that now-missing virtual
device driver (VxD) file, thereby eliminating the error messages that appear at system boot-up time.
Another Windows Registry editor, REGEDT32.EXE, is available to modify the Registry manually. It
displays the Registry hives as a series of folders. You can use either registry editor, but Microsoft (and the
author) recommend using REGEDIT.EXE.
BE CAREFUL, HOWEVER, WHEN RUNNING REGEDIT ... even the experts at Microsoft recommend
that you not use Regedit unless you know exactly what you are doing. Usually, it is better to reinstall the
missing software, or uninstall the errant software, rather than messing around with the Registry. When
you uninstall a software application, the uninstaller edits the Registry for you, removing all mentions of
any VxDs or drivers that will no longer be needed.
It is much better to let the software developer's uninstaller change the Registry, rather than you,
especially since they know what Registry entries were made in the first place.
Please use this guide when editing a Registry, and don't add or delete anything unless you are absolutely
sure that it is the right thing to do.
For the A+ examination, you will need to know what the Windows Registry is, what are the major
classes (or hives) within the Registry, how to edit the Registry (use Regedit), and how to restore your
backup registry in the case of emergency.
Re-Registering programs using Windows Explorer and .REG files
From time to time, you may find that certain programs will begin to malfunction because the Registry
entries for that program have become corrupt. The corruption may come from a virus, from another
installed program with competing Registry values (i.e., Internet Explorer vs. Firefox), from user error, or
from other miscellaneous problems (disk space corruption, installer failure, etc.).
When this occurs, there is a process you can use to re-register a program in the Windows Registry
without forcing a reload of the operating system. This process should restore a program to normal
operation.
To re-register a program in Windows, right-click on Start, then launch Windows Explorer. Select Tools
from the menu bar, then select Find, then select Files/Folders, and then search for any files on the hard
disk that end in .REG.
Find the .REG file that correlates to the affected program, and then re-register affected program by
double-clicking on the selected .REG file. This should restore the program to normal operation.
If this process does not return the computer to normal operation, contact the program’s technical support
staff for assistance.
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A discussion of various file systems used in Microsoft operating systems
FAT16 and FAT32 file systems - hard drives
From DOS version 4.0 through the "A" release of Windows 95, there was one major type of partition table
and file system for hard disks: the FAT16 file system. The FAT16 file system had two major problems;
large allocation unit sizes, and limited disk size addressing. As hard disks grew in size, the allocation unit
(the basic storage unit on hard disks) grew in size, finally topping out at 32,767 bytes per unit. If someone
stored a 150-byte in a 32,767-byte allocation unit, the user would lose 32,716 bytes as wasted space,
since DOS (and Windows 95) cannot put another file into an allocation unit that has a complete file (or
portion of a complete file) in it. Further, FAT16 file systems can only address 2 gigabytes (GB) of disk
space at a time. As hard disks grew beyond the 2GB barrier, this meant having to partition drives into
multiple 2GB or smaller partitions. The FAT16 file system now is functionally obsolete.
With the "B" release of Windows 95, a new type of file system was introduced. The FAT32 file system
corrected some of the major problems with FAT16 file systems. FAT32 file systems use allocation units of
4,096 bytes per unit, rather than 32,767 bytes. This meant much less wasted space on a hard disk, and
better utilization of the entire disk space. Further, FAT32 file systems can address up to 4 terabytes (TB)
of disk space, which is an enormous amount of disk space. There are virtually no compatibility problems
with older applications running in a FAT32 file system environment. With the introduction of Windows 98,
a utility was included that allowed a FAT16 file system to be converted to FAT32 with no need to reformat
the drive and reinstall the operating system.
The only problem with FAT32 file systems is that Windows NT version 4.0 does not recognize FAT32 file
systems. Windows NT 4.0 only recognizes the FAT16, NTFS (the file system for Windows NT and
above), and the CDFS (CD-ROM file system) file system types. If your hard disk was formatted as
FAT32, you would have to reformat the drive to FAT16 or NTFS in order to install Windows NT 4.0 on the
system. Windows 2000 / XP / Vista / Windows 7 are capable of reading a FAT32 disk, as well as FAT16,
previous versions of NTFS, and CDFS file systems.
CDFS file system - CD/DVD-ROM drives
Short for CD-ROM File System, CDFS (also referred to as ISO 9660) is a 32-bit file system that runs in
protected mode that allows Windows-based operating systems to read and write data to optical drives.
In addition, CDFS uses the VCACHE driver to control the CD-ROM disk cache, which results in much
smoother disc playback.
Comparisons and contrasts between NTFS and FAT file systems
Windows NT/2000/XP/Vista/Windows 7 uses the NTFS (NT File System) file system for hard disks, which
allows users and administrators to implement file and folder-level security, disk quotas, disk compression
and file encryption. Windows 95, 98 and ME use FAT16 or FAT32 file systems that do not permit for such
added levels of security.
Further, Windows NT does not recognize the FAT32 file system developed for Windows 9x. Windows NT
does recognize the FAT16 file system, but it is unable to implement the kinds of security levels possible in
an NTFS disk partition. The FAT16 file system does support the simultaneous loading of Windows 9x and
Windows NT on the same partition, permitting then a dual-boot configuration, but Windows 9x does not
recognize NTFS disk partitions.
However, Windows 2000/XP/Vista/Windows 7 does recognize the FAT32 file system that Windows NT
did not recognize. The file system for Windows NT has been called NTFS version 4 by Microsoft, NTFS
5.0 for Windows 2000, NTFS 5.1 for Windows XP, and NTFS 6.0/6.1 for Windows Vista / 7.
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Boot sequence for Windows NT / 2000 / XP / Vista / Windows 7 / Windows 8 and 8.1
Here is the boot sequence for Windows NT through Windows 8.1:
1)
The program NTLDR begins the boot process. It is located in the boot sector of the hard drive, and
it will allow for the computer to be booted to either Windows or to DOS-based operating systems
(such as Windows 9x and/or DOS). This is the Windows boot-loader program.
2)
BOOT.INI is used to determine how the computer will boot up, and which operating system will be
used. BOOT.INI is also used to create a Boot Loader Menu that is displayed on the screen prior to
the rest of the operating system loading. The default setting is that Windows
(NT/2000/XP/Vista/Windows 7/8/8.1) will be the default operating system, and the user has 30
seconds to make a choice of which operating system to boot with.
3)
The program BOOTSECT.DOS is loaded by NTLDR only if an operating system other than
Windows is loaded. NTLDR determines this by what choice is made at the Boot Loader Menu.
4)
NTDETECT.COM is loaded; it examines the hardware available in the system, and passes this
information to NTLDR for it to add to the Windows Registry. Pressing the spacebar at this point
bypasses the hardware detection process and invokes the last known good hardware profile
(from the last time Windows booted up; the operating system keeps a record of the last good
hardware profile).
5)
NTBOOTDD.SYS is loaded if there are non-booting SCSI devices in the system that need to be
recognized. If there is a SCSI boot device, the SCSI BIOS loads the necessary code for Windows
to recognize it. However, non-booting SCSI devices require a device driver at the operating
system level for them to operate. NTBOOTDD.SYS provides Windows with the code needed to
use these SCSI devices.
6)
The program NTOSKRNL.EXE loads into memory; this is the operating system kernel. In
Windows NT, a blue screen is displayed; in Windows 2000 through Windows 7, the Windows logo
is displayed.
7)
The file HAL.DLL is loaded. This loads the Hardware Abstraction Layer, which is the system-level
code that makes Windows portable to various system platforms.
8)
The program SYSTEM is loaded; it loads the system configuration settings to control device
drivers and services loaded as Windows initializes.
9)
Finally, any necessary device drivers are loaded to make specific devices (i.e., video card,
modem, sound card) operate. In Windows, the Plug-and-Play manager loads the necessary
drivers, and prompts the user to install a driver for any new devices detected in the system.
10)
Then, WINLOGON.EXE and EXPLORER.EXE are loaded; these programs provide the user
interface common to Windows, and also allow you as a user to log onto the system. Pressing
Ctrl-Alt-Delete brings up the login screen, which allows users to gain access to the system.
You will need to know the boot order in Windows, and the names (and functions) of the files needed for
Windows to load onto your PC, for the A+ examination.
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Trouble-shooting operating system installations
What to do when Windows (or another operating system) does not install properly
Normally, the operating system of your choice should install itself on your computer just fine, with a
minimum of problems. A specialized script file, called an .INF file, contains the instructions needed for the
install program to correctly run on your computer, and it has instructions to follow if it encounters specific
issues or problems while installing the operating system.
However, there may be specific problems on your computer that the script file cannot overcome, and the
install program may bomb (quit abruptly) on you unexpectedly. When that happens, you should explore
the following issues before calling Microsoft (or your vendor) for assistance.
Below are some possible reasons why Windows (or any other operating system) will not install properly.
System board misconfiguration
If your system board has something misconfigured in the CMOS Setup program, your operating system
(or other software) install program may bomb. Use the instructions contained in this guide on CMOS
Setup Configuration for assistance in correcting this type of problem. Many times, using the "Original"
default factory settings will solve this type of problem. If it does not, you may want to explore some of
these issues listed below.
CPU speed over-clocking
Making a CPU operate at a speed that is faster than rated is easy to do, but it may cause specific kinds of
failures on your PC, especially when an operating system install disk is attempting to identify exactly what
type of components you have in your PC. You may also cause the CPU to overheat, which will
permanently damage the CPU and possibly the motherboard as well. Make sure that any CPU timing
jumpers, including voltage jumpers, have been set correctly on your PC before doing any software
installations (if the system board uses configuration jumpers).
Most newer motherboards will let you set the speed values for the CPU in the CMOS Setup program, or
the board will set these values automatically and NOT allow you to make changes. Intel CPUs typically
cannot be overclocked, but AMD CPUs can be set to higher speed levels.
CPUs must be set to a specific megahertz speed, a specific clock multiplier, and a specific
voltage level ... make sure you have set your system board correctly before proceeding very far with any
software (or hardware) installations. Use the documentation from your system board, and also from your
CPU manufacturer, to ensure that these settings are correct.
Memory mismatches, mistimed memory, and memory failures
Random Access Memory (RAM) can be very finicky, and so can certain types of motherboards. When
adding memory to a system, it is important that you install memory SIMMs (Single In-line Memory
Module) or DIMMs (Dual In-line Memory Module) that match each other in type and speed. The SIMMs or
DIMMs don't have to have the same memory size, but they must run at the same speed, and they must be
the same type (i.e., fast page, EDO, synchronous DRAM, etc.). Also, you should never install both SIMMs
and DIMMs on the same system board, UNLESS the manufacturer's documentation explicitly states that
it is OK so to do. Usually DIMMs run at 10 - 20 nanoseconds (or less), while the fastest SIMMs run at 55
to 70 nanoseconds. Pushing those SIMMs to keep pace with the much-faster DIMMs will certainly cause
memory failures, and may cause the over-heating of the SIMMs as well.
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Secondly, the CMOS Setup program may have an option under the Advanced Chipset Features where
you can set the memory timing. It is usually best to set this option to AUTO, and let the motherboard
automatically determine the speed of the memory units. If you do set this option manually, set the value to
exactly what the memory speed is rated. The factory that manufactured the memory will have marked the
speed rating on the chips, usually with something like "-6" or "-60" (for 60 nanoseconds).
If the system board will not let you set the speed correctly, select a speed that is SLOWER than the chips
are rated. Faster SIMMs can go slower, but slower SIMMs can't reliably go faster.
Finally, do NOT assume that since the memory is new, it must be in good working condition. If you
encounter memory that you suspect is defective, use a memory tester to check the SIMM or DIMM in
question. If such a tester is not available, install the memory into a known-good system board and see
whether it works correctly or not. Return any defective memory to your vendor for replacement.
Cache memory failures
Cache memory is just as likely to fail as traditional SIMMs or DIMMs. Many Level 2 cache (also known as
the external cache) memory units are made as proprietary plug-in modules, or are chips that plug into
sockets on the motherboard, or may even be soldered into the system board. Level 1 cache (also known
as the internal cache) is built into the CPU itself; if that cache is blown (usually from overheating), the
CPU must be replaced.
Cache memory failures manifest themselves as an inability to get to a C: prompt, even when it seems that
the system is attempting to boot normally. Also, cache memory failures can cause random lockups and
illegal operation errors while in Windows.
If you suspect that there may be a cache memory failure in the system board, start by disabling the Level
2 cache in the Advanced CMOS Setup part of the BIOS Setup program. If the cache cannot be disabled
in the setup program, simply remove the cache memory from the system board. If this resolves the
problem, replace the Level 2 cache, re-enable the cache in the Setup program, then test the system
again. If the system still fails with a known good Level 2 (or L2) cache unit, the system board should be
replaced, or you can look at some other options listed in this section of the curriculum.
Hard disk problems
As with memory units, you cannot be assured that a new hard drive is in perfect working condition. The
best first way to determine if a drive is working correctly is to perform an auto-detect of the drive from the
CMOS Setup program. If the drive is correctly detected, make sure to select the option for logical block
addressing (LBA) mode if applicable, and make sure that the specifications match up to the
manufacturer's documentation.
If the drive is not detected, then the drive is not connected to the drive cable (or power cable) correctly, or
the drive's master/slave jumpers are not set correctly, or the drive is not operating at all, or the drive
interface may not be functioning correctly.
If the drive is detected but disk problems persist, run SCANDISK on the disk to determine the nature of
the problem. If uncorrectable errors exist on the disk in significant numbers (five percent or more of the
total disk space), or if the drive continually develops new disk flaws, replace the drive.
If the drive is under warranty, be sure to contact your vendor or drive manufacturer for assistance in
replacing the drive. Most hard disks have a 2 - 3 year warranty on them, so be sure to look at the
manufacture date to see if you are still in the warranty period. Contact the drive manufacturer for details
on how to return an in-warranty drive (called the Return Merchandise Authorization, or RMA, process).
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If the disk still has unusual errors on it, dump everything off the disk, reinstall the operating system, and
then scan the disk for viruses. Be sure to use clean, non-viral, write-protected disks when installing the
operating system or checking for viruses.
CD-ROM read failures and installation disk failures
Many newer CD-ROM drives have problems with vibration when operating at maximum speed. These
problems will cause intermittent read failures ... if such failures happen when you are installing an
operating system or application software, the install program may bomb on you. The only way to prevent
or recover from such problems is to buy well-known brand-name CD-ROM drives that have a good
reputation for consistent operation. Buying cheap CD-ROM drives may end up costing you valuable time
and endless frustration when installing your operating system.
Also, if you have problems with the CD-ROM drive not being read correctly, try to use the manufacturer’s
driver software that actually came with the drive. A Toshiba or Mitsumi brand driver may work on a
"no-name" drive, but occasionally these drivers will fail to operate your "no-name" drive ... using the
manufacturer-supplied drivers should remedy the problem.
Further, you may find that your operating system or application software has been duplicated onto cheap,
flimsy or defective CD-ROM disks (or floppy disks). Make sure that the data surface of your CD-ROM
disks are clean, fingerprint-free, and have as few scratches as possible. If there are imperfections in the
disk media, obtain replacement disks from the manufacturer or vendor. A little bit of Pledge furniture
polish on the CD may clean up a balky install disk, but be sure to wipe the disk totally clean before
inserting it into the drive.
System board or major component failures
Your install process may uncover for you some flaw in the system board, or some major component, like
a drive interface or video card. When you suspect that this is happening, use the course diagnostic DVD
to assure yourself that all of the system components are working properly. If something is defective, note
this and return the component to your vendor or manufacturer for replacement. Also, notice if something
is getting hot on the system board; this is usually a good indicator that something is defective.
Video RAM failure on a video card
Occasionally, your install process may find that the video RAM on the video card is defective. This
manifests itself as an inability to display video correctly, or an inability to use the entire color palette, or
when Windows will only boot to safe mode, or you get a constant error message that your video card is
incorrectly configured. When you suspect that this is happening, use a good general-purpose PC
diagnostic program to assure yourself that the video card is working properly. You can also swap in a
known-good video card to see if the problem goes away. If something is defective with the video card,
note this and return the component to your vendor or manufacturer for replacement.
Windows incorrectly installs components or features
Many times Windows will incorrectly install a component in your system when you first load the operating
system. For example, many times you will find that off-brand sound cards will be installed as "Other
Devices" instead of "Sound, video and game controllers". When that happens, delete the mentions of the
improperly installed device from the "Other Devices" section of the Windows Device Manager, and then
run the driver install disk for that device that came from the hardware manufacturer. This will typically
solve the problem, and allow the affected device to operate normally.
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Windows upgrade problems
Windows can be a real mess if you are not prepared with the right driver software for your computer.
Many Windows users are now reporting that when they install an upgrade to the operating system, the
sound card, modem or video card drivers on their computers go haywire. That is because many of the
core .DLL files and driver files that came with the previous Windows version do not (or may not) work with
the newer Windows operating system or the updated drivers that came with the upgrade.
Each Windows operating system version will have an entirely new set of Dynamic Link Library (.DLL) files
that have the same names as their older Windows counterparts. Even though the new Windows DLL files
have the same names as their previous version’s counterparts, these files are not necessarily compatible
with certain drivers or install scripts.
Make sure that you have drivers that are designed to work in your current (or upgraded) Windows
environment. You will need to check with your hardware vendor or manufacturer to make sure that
everything is in order before doing any installation work.
Viruses and malware
A virus, especially a boot sector virus or a stealth virus, can easily corrupt an operating system or
application install program. Be sure that your install disks are clean before beginning the installation;
check the disks on a known-clean system with a reputable anti-virus program (AVG Anti-Virus, for
example).
The author recommends that you run an anti-virus program, a good anti-malware application (like
MalwareBytes), and also a disk cleanup program like CCleaner on your hard disk before performing an
operating system installation or upgrade.
Further, be sure to disable any virus-protecting terminate-and-stay-resident (TSR) programs before
doing any kind of software installation ... many software installation programs appear to be viral to the
TSR program, and may cause the install program to bomb.
Using original system installation disks
Whenever possible, use only the original system disks to install any software program. This ensures that
no strange errors crop up when loading your software. If you do use backup diskettes, make sure that
they are exactly the same as the original disks.
Upgrade disks vs. full-installation (OEM) disks
There are two different types of software installation disks available from the manufacturer: original
equipment manufacturer full-install disks, and upgrade disks. Full-install, original equipment
manufacturer (OEM) disks presuppose that you have no software of any kind on your hard disk, or that
you do not have the previous revision of the specific software on your hard disk.
Upgrade disks are for those persons who have a previous version of the software on their hard disk
already, and who only need to move up to the most current version of the software.
Make sure you know which software package you need to do the installation, since the two packages are
NOT interchangeable. You cannot do a full install of any Windows version from the upgrade disk, and you
cannot upgrade any Windows version with an OEM full-install disk. Once you obtain the correct disk, you
will be able to successfully install your operating system or application.
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LBA Mode translations
Logical Block Addressing (LBA) mode allows the user to lie to the BIOS about the architecture (or
geometry) of the hard disk, so that the entire disk can be addressed as a single partition. Normally, hard
disks with more than 1024 cylinders cannot be addressed as a single unit, and must be partitioned and
addressed with special software, such as what comes with OnTrack's Disk Manager product.
LBA mode lets the user (and the computer) reduce the number of cylinders reported in the CMOS Setup,
while increasing the number of read/write heads by the same proportion in the setup program. By doing
this, you can use drives that are larger than 512 megabytes (the maximum of what could be addressed
without LBA mode) addressed as single partitions on your PC.
In order for this feature to work correctly, you must enable LBA mode in the CMOS Setup program
BEFORE performing an FDISK and FORMAT on the hard disk. If you don't do this, FDISK will partition
the disk only to 512MB in size, and you will need to delete the partition table, reboot, and re-FDISK the
drive in order to correct the problem. Most current PCs enable LBA mode by default.
Hard drives larger than 528 MB need to use the LBA (logical block addressing) mode feature in the
system BIOS for the whole drive to be recognized. ALL PCs have some form of LBA mode built into the
BIOS. Just like any other program, there are older and newer versions of the LBA translation feature.
However, some system BIOS products have an older version of the LBA mode feature that only will
recognize drives up to 127GB, or 1TB. If this is the case, you will need to upgrade the BIOS version with
software from the PC or system board manufacturer, or use a smaller drive that the current BIOS product
will accept.
Using EZ-Drive and other such disk translation programs
For those motherboards that do not have an up-to-date LBA mode version (or the BIOS cannot be
upgraded), there is a program called EZ-Drive that can potentially provide a solution. EZ-Drive provides
at a software level the same LBA translation capabilities that are found in the ROM BIOS firmware. It will
allow motherboards with older LBA versions to access and use hard drives larger than originally
designed. Many hard drive manufacturers provide a copy of EZ-Drive when you purchase a new drive.
HOWEVER, EZ-Drive may give you significant problems when running Windows, especially if your PC
becomes infected with a boot sector virus. In many cases, you will lose ALL your data on the disk,
because the boot sector virus significantly corrupts the LBA translation table written to the boot sector.
As a general rule, NEVER use EZ-Drive to install a hard disk on a computer UNLESS you know that the
motherboard does not support the LBA version you need, and you have no other options for upgrading
the system. Also, be sure to read the EZ-Drive documentation carefully BEFORE installing the drive
and/or your operating system on that drive.
Further, the ONLY way of getting rid of the EZ-Drive software on the hard disk (short of a low-level format)
is to use the EZ-Drive disk to UNINSTALL the software. Therefore, if you get a copy of the EZ-Drive install
disk, be sure to keep it, since you may need it to uninstall the software at a future date on some poor
soul's PC.
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Service packs from Microsoft
Instead of issuing revised versions of Windows (or other application programs), Microsoft made available
to the customer via their web site programs called service packs, which when run will update Windows
with revised versions of specific files that have had reported problems.
These service packs are available from Microsoft at no charge for Windows XP, Vista, Windows 7, and
also for the Microsoft Office XP/2003/2007/2010 suites. Service packs for older operating systems and
application suites are still available on the Internet, but Microsoft no longer makes these resources
available on their website.
These service packs are self-extracting archive files that will automatically unpack and then install the
proper components on your PC. If you encounter unusual problems on your PC, it is possible that running
a service pack upgrade may fix the problem.
Visit the Microsoft Download web site at http://www.microsoft.com/download for more details.
Differences between the various Windows operating systems
If you listen solely to Microsoft for information on the differences between operating systems, you may
only get a portion of the story. For example, Microsoft has information and charts on their website that
contrasts Windows XP, Vista, and Windows 7. A link to that chart is shown below:
http://www.microsoft.com/windows/windows-7/compare/versions.aspx
Of course, Microsoft will say the newest version of Windows is CLEARLY superior to the previous
versions. The author recommends doing a Google, Yahoo or Bing search on the phrase “comparing
Windows 7, Vista and XP.” This will yield hundreds of results from various sources that will give you a
more well-rounded presentation.
But how can you determine for yourself the differences between the various Windows operating
systems? In the course, we will take three identical computers and install Windows on each of them.
Then, we will perform identical tasks on all three computers, to see how each performs in real time.
Once this is done, we will perform upgrades on the designated Windows Vista and Windows 7
computers, to see what is required to bring them up to an acceptable performance level.
Minimum installation specifications for Windows operating systems
Microsoft provides on their website the minimum hardware specifications needed to install and run a
given Windows operating system version. Below are the MINIMUM specifications needed to run
Windows XP, Windows Vista, Windows 7, and Windows 8 / 8.1:
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Windows XP (Home and Professional)
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●
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PC with 300 megahertz or higher processor clock speed recommended; 233 MHZ minimum
required (single or dual processor system); Intel Pentium/Celeron family, or AMD
K6/Athlon/Duron family, or compatible processor recommended
128 megabytes (MB) of RAM or higher recommended (64 MB minimum supported; may limit
performance and some features)
1.5 gigabytes (GB) of available hard disk space
Super VGA (800 x 600) or higher-resolution video adapter and monitor
CD-ROM or DVD drive
Keyboard and Microsoft Mouse or compatible pointing device
NOTE: XP Home / Professional runs best with at least 512MB of RAM and at least a 1.0GHz CPU.
Windows Vista Home Basic
●
●
●
●
●
●
●
1 GHz 32-bit (x86) or 64-bit (x64) processor
512 MB of system memory
20 GB hard drive with at least 15 GB of available space
Support for DirectX 9 graphics and 32 MB of graphics memory
DVD-ROM drive
Audio Output
Internet access (fees may apply)
NOTE: Vista Home Basic runs best with at least 1.5GB of RAM and at least a 1.5GHz CPU.
Windows Vista Home Premium / Business / Ultimate
●
●
●
●
●
●
●
1 GHz 32-bit (x86) or 64-bit (x64) processor
1 GB of system memory
40 GB hard drive with at least 15 GB of available space
Support for DirectX 9 graphics with:
WDDM Driver
128 MB of graphics memory (minimum)
Pixel Shader 2.0 in hardware
32 bits per pixel
DVD-ROM drive
Audio Output
Internet access (fees may apply)
NOTE: Vista Home Premium / Business / Ultimate runs best with at least 2GB of RAM and at least a
1.8GHz CPU.
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Windows 7 (all versions)
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●
●
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1 gigahertz (GHz) or faster 32-bit (x86) or 64-bit (x64) processor
1 gigabyte (GB) RAM (32-bit) or 2 GB RAM (64-bit)
16 GB available hard disk space (32-bit) or 20 GB (64-bit)
DirectX 9 graphics device with WDDM 1.0 or higher driver
Additional requirements to use certain features:
●
●
Internet access (fees may apply)
Depending on resolution, video playback may require additional memory and advanced graphics
hardware
For some Windows Media Center functionality a TV tuner and additional hardware may be
required
Windows Touch and Tablet PCs require specific hardware
The HomeGroup feature requires a network and PCs running Windows 7
DVD/CD authoring requires a compatible optical drive
BitLocker requires Trusted Platform Module (TPM) 1.2
BitLocker To Go requires a USB flash drive
Windows XP Mode requires an additional 1 GB of RAM, an additional 15 GB of available hard disk
space, and a processor capable of hardware virtualization with Intel VT or AMD-V turned on
Music and sound require audio output
●
●
●
●
●
●
●
●
Product functionality and graphics may vary based on your system configuration. Some features may
require advanced or additional hardware.
NOTE: Windows 7 runs best with at least 2GB of RAM and at least a 2.0GHz CPU.
Windows 8 and 8.1




1 gigahertz (GHz)* or faster processor with support for PAE, NX, and SSE2
RAM: 1 gigabyte (GB) (32-bit) or 2 GB (64-bit) RAM
Hard disk space: 16 GB (32-bit) or 20 GB (64-bit) available hard disk space
Microsoft DirectX 9 graphics device with WDDM driver
Additional requirements to use certain features:










To use touch, you need a tablet or a monitor that supports multitouch
To access the Windows Store and to download and run apps, you need an active Internet
connection and a screen resolution of at least 1024 x 768
To snap apps, you need a screen resolution of at least 1366 x 768
Internet access (ISP fees might apply)
Secure boot requires firmware that supports UEFI v2.3.1 Errata B and has the Microsoft
Windows Certification Authority in the UEFI signature database
Some games and programs might require a graphics card compatible with DirectX 10 or higher
for optimal performance
Microsoft account required for some features
Watching DVDs requires separate playback software
BitLocker To Go requires a USB flash drive (Windows 8 Pro only)
BitLocker requires either Trusted Platform Module (TPM) 1.2 or a USB flash drive (Windows 8
Pro only)
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


Client Hyper-V requires a 64-bit system with second level address translation (SLAT)
capabilities and additional 2 GB of RAM (Windows 8 Pro only)
A TV tuner is required to play and record live TV in Windows Media Center (Windows 8 Pro
Pack and Windows 8 Media Center Pack only)
Free Internet TV content varies by geography, some content might require additional fees
(Windows 8 Pro Pack and Windows 8 Media Center Pack only)
NOTE: Windows 8 runs best with at least 4GB of RAM and at least a 2.0GHz CPU.
Microsoft does make available at no charge from their website the Windows Vista, Windows 7, and
Windows 8/8.1 Upgrade Advisor applications. These Upgrade Advisors will give you a more detailed
understanding of whether your PC can run Windows 8, Windows 7 or Windows Vista.
The author strongly recommends that you run these Upgrade Advisor applications BEFORE following
through with an operating system upgrade.
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Part 2: Linux Operating Systems
The Linux open source operating system, or Linux OS, is a freely distributable, cross-platform operating
system based on Unix that can be installed on PCs, laptops, netbooks, mobile and tablet devices, video
game consoles, servers, supercomputers and more. The Linux OS is frequently packaged as a Linux
distribution for both desktop and server use, and includes the Linux kernel (the core of the operating
system) as well as supporting tools and libraries.
Well-known distributions of Linux include Ubuntu, Linux Mint, Red Hat, Debian, CentOS, and others. All
of these distributions come with office suite software, driver support for thousands of devices, browsers
and chat applications, and programs to support audio and video playback from various types of files.
In 1983, a programmer named Richard Stallman creates the GNU Project. It is an attempt at creating a
Unix type operating system but composed of entirely free software. In 1987, a programmer Andrew S.
Tanenbaum creates Minix, a Unix like operating system for Academic use. Then in 1991, a Finnish
student named Linus Torvalds created a non-commercial version of Minix and calls it Linux. The Linu is
from Linus and the x is from the 'ix' part of Minix.
Since then, Linux has become the operating system of choice for servers, developers, programmers,
and people who want a stable, reliable operating system. Linux is far more secure than any version of
Windows has ever been, and Linux needs no antivirus application to keep it safe. In fact, the Android
operating system as well as the Apple Mac OS and Apple iOS are based upon Linux.
An online documentary called Revolution OS provides an excellent description of how Linux evolved
from its beginnings to the current day. A link to this movie documentary is shown below:
https://www.youtube.com/watch?v=fxjElWL8igo
Appendix E of this text provides a fuller description of the history and distinctives of Linux operating
systems. Please refer to this section for more information.
This portion of the text will provide you with information about the Linux operating system that will help
you to pass the A+ Certification examination.
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Basic Linux Commands
Beginning with the 220-902 A+ examination, you must know how to use some essential command-line
tools in Linux. These are DOS-like kinds of commands, but they are not the same as Microsoft DOS
command-line tools. Below is a list of the commands you will need to know for the A+ examination.
The apt-get command
apt-get is the command-line tool for working with APT software packages, such as program installers
and update packages.
APT (the Advanced Packaging Tool) is an evolution of the Debian .deb software packaging system. It is
a rapid, practical, and efficient way to install packages on your system. Dependencies are managed
automatically, configuration files are maintained, and upgrades and downgrades are handled carefully to
ensure system stability.
The cd command
The cd command is used to change the current directory (i.e., the directory in which the user is currently
working) in Linux and other Unix-like operating systems. It is similar to the CD and CHDIR commands in
MS-DOS.
cd's syntax is: cd [option] [directory]
The chmod command
In Linux and other Unix-like operating systems, there is a set of rules for each file which defines who can
access that file, and how they can access it. These rules are called file permissions or file modes. The
command chmod stands for "change mode", and it is used to define the way a file can be accessed.
chmod modifies the permissions of the file specified by filename to the permissions specified by
permissions.
Permissions defines the file access rights for the owner of the file, members of the group who owns the
file, and anyone else. There are two ways to represent these permissions: with symbols (alphanumeric
characters), or with octal numbers (the digits 0 through 7).
The chown command (including chgrp)
chown changes the user and/or group ownership of each given file. If only an owner (a user name or
numeric user ID) is given, that user is made the owner of each given file, and the files' group is not
changed.
If the owner is followed by a colon and a group name (or numeric group ID), with no spaces between
them, the group ownership of the files is changed as well. If a colon but no group name follows the user
name, that user is made the owner of the files and the group of the files is changed to that user's login
group.
If the colon and group are given, but the owner is omitted, only the group of the files is changed; in this
case, chown performs the same function as chgrp (change group). If only a colon is given, or if the entire
operand is empty, neither the owner nor the group is changed.
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The cp command
cp is the command which makes a copy of your files or directories. For example: you have a file named
picture.jpg in your working directory, and you want to make a copy of it called picture-02.jpg. You would
run the command:
cp picture.jpg picture-02.jpg
The file will be copied. Here, picture.jpg is the source of the copy operation, and picture-02.jpg is the
destination. Both files now exist in your working directory.
The source and destination files may also reside in different directories. For instance, the command
cp /home/bill/pictures/picture.jpg /home/bill/backup/picture.jpg
will make a copy of the file /home/bill/pictures/picture.jpg in the directory /home/bill/backup. The
destination file will also be named picture.jpg.
If you are the user bill, you can abbreviate your home directory (/home/bill) using a tilde ("~"). For
example:
cp ~/pictures/picture.jpg ~/backup/picture.jpg
This command will function the same as the previous command shown above, when it is run by the user
named bill.
If you want to copy multiple files into another directory, you can specify multiple files as the source, and a
directory name as the destination. Let's say you are the user joyce, and you have a number of files in the
directory /home/joyce/pictures/ named picture-01.jpg, picture-02.jpg, and so forth. You want to copy them
into the directory called /home/joyce/picture-backup/. This command will do what is described above:
cp ~/pictures/picture-*.jpg ~/picture-backup
Here, we use a wildcard (the asterisk, *) to indicate that the source files are all the files in the directory
/home/joyce/pictures whose name starts with "picture-" and have the extension .jpg. They will be copied
into the directory /home/joyce/picture-backup, assuming that this directory already exists. If the directory
does not exist, the cp command will give you an error message, and no files will be copied.
You can also specify multiple source files one after the other, and the cp command will expect that the
final argument is a directory name, and copy all the files to that location.
The dd command
dd is a command-line utility for Unix and Unix-like operating systems whose primary purpose is to
convert and copy files.
dd can be used for tasks such as backing up the boot sector of a hard drive, and obtaining a fixed
amount of random data. The dd program can also perform conversions on the data as it is copied,
including byte order swapping and conversion to and from the ASCII and EBCDIC text encoding
methods.
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The df command
The df command shows available disk storage space; use the –h command to show sizes in human
terms like MB or GB, as opposed to available disk blocks.
The free command
The free command shows memory usage on the PC; the –h option will make the results easier to
understand.
The grep command
grep is a command-line utility for searching plain-text data sets for lines matching a regular expression.
grep was originally developed for the Unix operating system, but is available today for all Unix-like
systems. Its name comes from the ed command g/re/p (globally search a regular expression and print),
which has the same effect: doing a global search with the regular expression and printing all matching
lines (to the screen, not to a printer).
The word grep was first used on Star Trek; it’s a Vulcan word that means “find”. Seriously …
The ifconfig and iwconfig commands
ifconfig is used to configure the system's kernel-resident network interfaces. It is used at boot time to set
up interfaces as necessary. After that, it is usually only needed when debugging, or when system tuning
is needed.



If no arguments are given, ifconfig displays the status of the system's active interfaces.
If a single interface argument is given, it displays the status of the given interface only.
If a single -a argument is given, it displays the status of all interfaces, even those that are "down"
(inactive).
In all other cases, ifconfig configures an interface according to the options provided by the user.
iwconfig is similar to ifconfig, but is dedicated to the wireless interfaces. It is used to set the parameters
of the network interface which are specific to the wireless operation (for example : the broadcast
frequency). Iwconfig may also be used to display those parameters, and the wireless statistics for that
device.
The kill command
The kill command kills (or stops) a running process; kill is often used with the ps or top command.
The ls command
The ls command is like the DIR command in MS-DOS; it lists all of the files in the current directory, or in
a specified directory.
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Without options, the ls command displays files in a bare format, without any details about the files. This
bare format however makes it difficult to establish the type, permissions, and size of the files. The most
common options to reveal this information or change the list of files are:








-l long format, displaying Unix file types, permissions, number of hard links, owner, group, size,
last-modified date and filename
-f do not sort. Useful for directories containing large numbers of files.
-F appends a character revealing the nature of a file, for example, * for an executable, or / for a
directory. Regular files have no suffix.
-a lists all files in the given directory, including those whose names start with "." (which are hidden
files in Unix). By default, these files are excluded from the list.
-R recursively lists subdirectories. The command ls -R / would therefore list all files.
-d shows information about a symbolic link or directory, rather than about the link's target or
listing the contents of a directory.
-t sort the list of files by modification time.
-h print sizes in human readable format. (e.g., 1K, 234M, 2G, etc.)
The mv command
The mv command allows the user to move a file (or files) from one location to another. This can be
somewhat confusing, because mv is also used to rename files. Here's an example:
You have the file called testfile in the /home/bill/ directory; you want to rename it to testfile2, and keep it
in the same directry. To accomplish this, you would use the mv command:
mv /home/bill/testfile /home/bill/testfile2
If you're already within the /home/bill directory, the command would look like this:
mv testfile testfile2
These commands shown above would move the file /home/bill/testfile to /home/bill/testfile2, and
effectively rename the file.
You could move that file called testfile into the /home/bill/Documents folder with this command:
mv /home/bill/testfile /home/bill/Documents/
With this command, you would move the file into that new location, while keeping the original file name.
Wildcard characters (like *) also can be used if you have a number of files that need to be moved.
The nano command
Nano is a text-editing utility available in some distributions of Linux; it is similar to the old edit command
available in MS-DOS operating systems.
The ps command
Linux has a built-in tool to capture current processes running on the system. The ps command gives a
snapshot of any or all current processes. It will “capture” the state of the system at that time.
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The pwd and the passwd commands
The pwd command in Linux shows the present working directory, in other words, the directory the user is
in right now.
The passwd command, however, changes passwords for user accounts. A normal user may only change
the password for his/her own account, while the superuser may change the password for any account.
passwd also changes the account or associated password validity period.
The user is first prompted for his/her old password, if one is present. This password is then encrypted
and compared against the stored password. The user has only one chance to enter the correct
password. The superuser is permitted to bypass this step so that forgotten passwords may be changed.
After the password has been entered, password aging information is checked to see if the user is
permitted to change the password at this time. If not, passwd refuses to change the password and exits.
The user is then prompted twice for a replacement password. The second entry is compared against the
first and both are required to match in order for the password to be changed.
Then, the password is tested for complexity. As a general guideline, passwords should consist of 6 to 8
characters including one or more characters from each of the following sets:



lower case alphabetics
digits 0 thru 9
punctuation marks
Care must be taken not to include the system default erase or kill characters. passwd will reject any
password which is not suitably complex.
The quota command
The quota command displays users' disk usage and limits. By default only the user quotas are printed.
The rm command
The rm command removes specified FILES. By default, it does not remove directories.
The removal process unlinks a filename in a filesystem from data on the storage device, and marks that
space as usable by future writes. In other words, removing files increases the amount of available space
on your disk.
The data itself is not destroyed, but after being unlinked, it becomes inaccessible. Be VERY CAREFUL
when using the rm command! The effects of an rm operation cannot be undone.
If what you want is to completely, unrecoverably erase the data on the disk, use the shred command
instead. This will overwrite the file's contents so that they cannot be reconstructed later by any means.
When using rm, if the -I or --interactive=once option is given, and there are more than three files or the -r,
-R, or --recursive are given, rm will prompt the user for whether to proceed with the entire operation. If
the response is not yes, the entire command is aborted.
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The shutdown command
The shutdown command brings the system down in a secure way. All logged-in users are notified that
the system is going down, and login operations are blocked. It is possible to shut the system down
immediately, or after a specified delay.
All processes are first notified that the system is going down by the signal SIGTERM. This gives
programs like vi time to save the file being edited, and gives mail and news processing programs a
chance to exit cleanly.
The shutdown command does its job by signalling the init process, asking it to change the operating
system runlevel. Runlevel 0 is used to halt the system, runlevel 6 is used to reboot the system, and
runlevel 1 is used to put the system into a state where administrative tasks can be performed (singleuser mode). Runlevel 1 is the default, unless the -h or -r options are specified.
The su/sudo commands
sudo is a command that allows users to run programs with the security privileges of another user, by
default the superuser. It originally stood for "superuser do" as the older versions of sudo were designed
to run commands only as the superuser.
However, the later versions added support for running commands not only as the superuser but also as
other (restricted) users, and thus it is also commonly expanded as "substitute user do". Although the
latter case reflects its current functionality more accurately, sudo is still often called "superuser do" since
it is so often used for administrative tasks.
Unlike the related command su, users must supply their own password for authentication, rather than the
password of the target user. After authentication, and if the configuration file, which is typically located at
the folder /etc/sudoers, permits the user access, the system invokes the requested command.
The configuration file offers detailed access permissions, including enabling commands only from the
invoking terminal; requiring a password per user or group; requiring re-entry of a password every time or
never requiring a password at all for a particular command line. It can also be configured to permit
passing arguments or multiple commands.
The service command
The service command allows services or daemons to be turned on, off, or reset (i.e., service apache
stop).
The top command
The top command is like the Windows Task Manager, but for the console.
The vi command
vi is an interactive text editor which is display-oriented: the screen of your terminal acts as a window into
the file you are editing. Changes you make to the file are reflected in what you see.
Using vi you can insert text anywhere in the file very easily. Most of the vi commands move the cursor
around in the file. You can move the cursor forward and backward in units of characters, words,
sentences, and paragraphs. Some of the operators, like d for delete and c for change, can be combined
with the motion commands to make them operate on entire words or paragraphs.
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Part 3: Macintosh Operating System
When the A+ Certification examination was first rolled out many years ago, one could be certified in
either Microsoft or Apple Macintosh operating systems. For many years, the Mac OS did not appear as a
part of the certification process. Now with the 220-901 and 220-902 examinations, the Mac OS has
returned as a part of the certification program.
The reasons to include the Mac OS are clear. More and more people are using Apple Macs and
MacBooks, and people need to have technicians that can service both PCs and Macs. The operating
system on a Mac, called OS X, is quite similar to Linux-based operating systems, and not too dissimilar
to the Windows operating system. In fact, it was Apple who first introduced the concept of a graphical
user interface (GUI) for consumers to use with the original Macintosh. Microsoft then had to scurry to
develop Windows, in order to compete with Apple.
In terms of hardware, a Mac or MacBook is not terribly different to service than a PC or Windows-based
laptop. You will need some specialized tools in order to open the cases, but once they are open the
similarities will become obvious.
There is no Setup program on a Mac, unlike with a traditional Windows based computer. The Mac
supports full plug-and-play functionality, and has done so ever since the original Macintosh computers
were introduced in 1984. You will not need to search the Web or a manufacturer’s website for hardware
drivers for any given device; all the driver support you will ever need is built into the operating system.
In terms of the operating system, the same basic principles will apply to both Windows and the Mac OS.
Drag-and-drop, cut-and-paste, copying/moving/deleting files, all will be essentially the same in both
environments.
Because the Mac operating system is essentially built around the Linux kernel, it is nearly impervious to
any kind of viral or malicious software. Certainly any Windows-based viruses will have absolutely no
effect on a Mac whatsoever. Antivirus and anti-malware programs for the Mac OS do exist, but they are
not truly necessary, in the opinion of the author.
There are some key features in the Mac OS you will need to know about in order to pass the A+
Certification examination. This section of the text will cover these key points.
Boot Camp
Boot Camp is a multi-boot utility included with Apple Inc.'s OS X that assists users in installing Microsoft
Windows operating systems on Intel-based Macintosh computers. The utility's Boot Camp Assistant
guides users through non-destructive disk partitioning (including resizing of an existing HFS+ partition, if
necessary) of their hard disk drive and installation of Windows device drivers for the Apple hardware.
The utility also installs a Windows Control Panel applet for selecting the boot operating system.
Disk Utility
Disk Utility can verify your computer's startup disk (volume) without starting up from another volume. This
feature is called "Live Verification." If Disk Utility discovers any issues that require a repair, you will need
to start up from your Mac OS X Install DVD and use Disk Utility on that disc to make repairs (You can't
repair your startup volume while your computer is started from it.).
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Dock
In the Apple OS X operating system , the dock is a user-modifiable row of function or application icon s
that appear on the computer desktop so that the user can find and select any of them quickly. The user
can reposition the dock and also elect to have each function or application icon magnify as the user rolls
the mouse over it.
The OS X dock is generally comparable to the taskbar in a Windows operating system. The dock should
not be confused with a docking station.
Finder
The Finder is the default file manager and graphical user interface shell used on all Macintosh operating
systems. Described in its "About" window as "The Macintosh Desktop Experience", it is responsible for
the launching of other applications, and for the overall user management of files, disks, and network
volumes. It was introduced with the first Macintosh computer, and also exists as part of GS/OS on the
Apple IIGS. It had been rewritten completely with the release of Mac OS X in 2001.
In a tradition dating back to the classic Mac OS of the 1980s and 1990s, the Finder icon is the smiling
screen of a computer, known as the Happy Mac logo.
The Finder uses a view of the file system that is rendered using a desktop metaphor; that is, the files and
folders are represented as appropriate icons. It uses a similar interface to Apple's Safari browser, where
the user can click on a folder to move to it and move between locations using "back" and "forward" arrow
buttons. Like Safari, the Finder uses tabs to allow the user to view multiple folders; these tabs can be
pulled off the window to make them separate windows. There is a "favorites" sidebar of commonly used
and important folders on the left of the Finder window.
Gestures
Gestures offer you a smart, intuitive way to work with your Mac. When you use a Magic Mouse, Magic
Trackpad, or a Multi-Touch trackpad on a portable Mac, you can use gestures, such as click, tap, pinch,
and swipe, to zoom in on documents, browse through music or webpages, rotate photos, and much
more.
With OS X, you’ll enjoy even more fluid and realistic gesture responses, including rubber-band scrolling,
zooming, and full-screen swiping.
iCloud
iCloud is a suite of free cloud-based services from Apple that helps users store and synchronize digital
content across computers and numerous iOS-supported devices such as iPhones, iPads and iPod
Touches.
Key Chain
Keychain is password management system in OS X developed by Apple. It was introduced with Mac OS
8.6, and has been included in all subsequent versions of Mac OS, including OS X. A Keychain can
contain various types of data: passwords (for websites, FTP servers, SSH accounts, network shares,
wireless networks, groupware applications, encrypted disk images), private keys, certificates, and secure
notes.
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Multiple desktops/Mission Control
Mission Control, formerly called Exposé, is a feature of the OS X operating system. Mission Control
allows a user to quickly locate an open window, quickly hide all windows and show the desktop, and to
manage windows across multiple monitors or virtual desktops. Exposé was renamed to Mission Control
in 2011 with the release of OS X Lion.
Remote Disc
The Remote Disc feature of OS X lets you use files stored on a CD or DVD hosted from another
computer.
If a Mac doesn't have a built-in optical drive and you need to use a CD or DVD, you can connect an
external drive like the Apple USB SuperDrive. You can also share discs from the optical drive of another
Mac, or from a Windows computer that has DVD or CD Sharing Setup installed. DVD or CD sharing
allows you to access documents stored on these discs, and allows you to install some software.
Spot Light
Spotlight helps you quickly find anything on your Mac, including documents, emails, apps, songs,
contacts, and more. It also provides Spotlight Suggestions from sources like Wikipedia, Bing, Maps,
news, and iTunes so you can get more information right in Spotlight. Search results have rich, interactive
previews so you can play song previews, get directions, send email, make phone calls, and more from
results.
Time Machine
Time Machine is a backup software application distributed with the Apple OS X computer operating
system. The software is designed to work with the Time Capsule storage product, as well as other
internal and external disk drives. It was introduced in Mac OS X Leopard.
Time Machine creates incremental backups of files that can be restored at a later date. It allows the user
to restore the whole system or specific files from the Recovery HD or the OS X Install DVD. It works
within iWork, iLife, and several other compatible programs, making it possible to restore individual
objects (e.g. photos, contacts, calendar events) without leaving the application.
More information about the Apple Mac operating system can be found at Apple’s support website:
https://www.apple.com/support/
NOTES
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Part 4: Virtualized Operating Systems and Cloud Computing
The A+ Certification examination now covers key aspects of client-side virtualized environments. This is
because so many companies are using virtualization to achieve business goals, especially as It relates to
distributed computing and telework. This portion of the text will cover key aspects of virtualization that
you will need to understand in order to pass the A+ Certification examination.
Client-side virtualization
A client-based virtual machine is an instance of an operating system that is managed centrally on a
server and executed locally on a client device. Although the operating system disk image is updated
and backed up by synchronizing regularly with a server, a constant network connection is not necessary
for a client-based virtual machine to function.
A client-based virtual machine can run without a host operating system directly on a type 1 (or baremetal) hypervisor, or at the same time as a host operating system, utilizing a type 2 hypervisor. The
hypervisor provides an interface to the local hardware, taking the place of drivers that would normally
be contained in an operating system image. This allows virtual machine images to be standardized and
usable across a large variety of different hardware configurations.
Many businesses and Federal agencies use virtualization solutions to allow employees to telework,
rather than having to come into the office for some portion of their work week. Employees can telework
using desktop or laptop computers, Macs, tablets, or other Internet-capable devices (like smartphones).
However, in order to enable more advanced functionality, virtual machines must often reach through the
hypervisor and interact with the local host hardware directly. This requires the virtual machine to have
specific drivers for the hardware on which it is running, negating the benefits of a standardized image.
Despite this drawback, many benefits of centralized management remain, including the ability to easily
back-up, secure, encrypt, and repair disk images.
Resource requirements for client-side virtualization
Different types of software require specific amounts of available resources to install and then provide
optimal performance. If resources are insufficient, the software and the operating system will take more
time for processing data and performance may suffer. Virtual machine applications allow you to allocate
memory sufficient for proper operation. You also can control settings that determine how much of the
host computer's CPU resources shall be available to the virtual machine.
Emulator requirements
Virtual machine applications can emulate, or make something look and work like, another type of
computer. For example, a Windows-based virtual desktop can be run in a window on an iPad or Android
tablet. In addition to the hardware requirements needed for client-side virtualization, the virtualization
application needs to be able to emulate the required software environment on a number of different
hardware platforms.
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Network requirements
People using virtualized environments must be able to log into and authenticate to the host system.
Further, unauthorized individuals need to be kept out of the secure systems. Many organizations using
virtualized desktop solutions will use two-factor authentication to ensure that only authorized persons can
access the resources. In addition to a username and password combination, users may need to enter a
PIN number and an RSA passcode (for example) from a hardware token or RSA smartphone application
in order to login. The passcode number on these tokens change every 60 seconds, to ensure that only
authorized persons can log into the system.
Security requirements
Virtualized environments need to have security built into the applications, to ensure that hackers cannot
gain access to what could potentially be restricted environments. Applications like Citrix and VMware use
both 128-bit encryption and Layer 2 Tunneling Protocol (L2TP) to keep virtual sessions secure.
Basic cloud computing concepts
What exactly is “cloud computing”? Simply put, it means that the application you are using and/or the
data you are creating is housed and stored somewhere on the Internet. If you use Internet email services
like Gmail, you are using cloud-based email. The application is run through your browser or an app on
your tablet or smartphone, and everything else happens at some data center that is connected to the
Internet. Many applications, like Office365, are run within the cloud.
There are several key terms you will need to know for the A+ examination with regard to cloud
computing:
IaaS
Infrastructure as a Service (IaaS) is a form of cloud computing that provides virtualized computing
resources over the Internet.
In an IaaS model, a third-party provider hosts hardware, software, servers, storage and other
infrastructure components on behalf of its users. IaaS providers also host users' applications and handle
tasks including system maintenance, backup and resiliency planning.
IaaS platforms offer highly scalable resources that can be adjusted on-demand. This makes IaaS wellsuited for workloads that are temporary, experimental or change unexpectedly.
Other characteristics of IaaS environments include the automation of administrative tasks, dynamic
scaling, desktop virtualization and policy-based services.
IaaS customers pay on a per-use basis, typically by the hour, week or month. Some providers also
charge customers based on the amount of virtual machine space they use. This pay-as-you-go model
eliminates the capital expense of deploying in-house hardware and software. However, users should
monitor their IaaS environments closely to avoid being charged for unauthorized services.
Measured service
Measured service is a term that IT professionals apply to cloud computing. It refers to services where the
cloud provider measures or monitors the provision of services for various reasons, including billing,
effective use of resources, or overall predictive planning.
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PaaS
Platform as a service (PaaS) is a category of cloud computing services that provides a platform allowing
customers to develop, run, and manage web applications without the complexity of building and
maintaining the infrastructure typically associated with developing and launching an app.
PaaS can be delivered in two ways: as a public cloud service from a provider, where the consumer
controls software deployment and configuration settings, and the provider provides the networks,
servers, storage and other services to host the consumer's application; or as software installed in private
data centers or public infrastructure as a service and managed by internal IT departments.
Public vs. Private vs. Hybrid vs. Community Clouds
A public cloud is just what it sounds like: everyone can use it. You may have an account with a
username and password, but that it to ensure the privacy of your account.
Public clouds, such as those from Amazon Web Services (AWS) or Google Compute Engine (GCE),
share a computing infrastructure across different users, business units or businesses.
By comparison, a private cloud would be used (for example) by businesses or government agencies for
their employees’ use. Shared computing environments like AWS aren't suitable for all businesses, such
as those with mission-critical workloads, security concerns, uptime requirements or management
demands. Instead, these businesses can provision a portion of their existing data center as an onpremises -- or private -- cloud.
A private cloud provides the same basic benefits of public cloud. These include self-service and
scalability; multi-tenancy; the ability to provision machines; changing computing resources on-demand;
and creating multiple machines for complex computing jobs, such as big data. Chargeback tools track
computing usage, and business units pay only for the resources they use.
In addition, private cloud offers hosted services to a limited number of people behind a firewall, so it
minimizes the security concerns some organizations have around cloud. Private cloud also gives
companies direct control over their data.
A hybrid cloud is a cloud computing environment which uses a mix of on-premises, private cloud and
third-party, public cloud services with orchestration between the two platforms. By allowing workloads to
move between private and public clouds as computing needs and costs change, hybrid cloud gives
businesses greater flexibility and more data deployment options.
A community cloud is a multi-tenant infrastructure that is shared among several organizations from a
specific group with common computing concerns. Such concerns might be related to regulatory
compliance, such as audit requirements, or may be related to performance requirements, such as
hosting applications that require a quick response time, for example.
Rapid Elasticity
Rapid elasticity is a cloud computing term for scalable provisioning, or the ability to provide scalable
services. Experts point to this kind of scalable model as one of five fundamental aspects of cloud
computing.
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Rapid elasticity allows users to automatically request additional space in the cloud or other types of
services. Because of the setup of cloud computing services, provisioning can be seamless for the client
or user. The fact that providers still need to allocate and de-allocate resources is often irrelevant on the
client or user's side. This is a very essential aspect of cloud technology. In a sense, cloud computing
resources appear to be infinite or automatically available.
Resource pooling
Resource pooling is an IT term used in cloud computing environments to describe a situation in which
providers serve multiple clients, customers or "tenants" with provisional and scalable services. These
services can be adjusted to suit each client's needs without any changes being apparent to the client or
end user.
SaaS
Software as a Service (SaaS) is a software distribution model in which applications are hosted by a
vendor or service provider and made available to customers over a network, typically the Internet.
NOTES
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Chapter 12. Installing Application Software and Operating Systems
Once an operating system has been installed, application software will be installed to the computer's hard
disk. This is a typical task for a computer technician, as well as for the typical user. This section of the text
will instruct you in how to install properly different types of application software.
How to install application software
Installing software has become relatively simple, especially with the advent of the CD-ROM drive. For
many programs, simply dropping the installation CD into the CD-ROM drive will cause the installation
program to begin. The program SETUP.EXE launches a script that takes care of installing of that
application's program files, and it also makes the necessary changes to the Windows Registry.
The preferred method, however, to install a new application is to go to the Windows Control Panel,
double-click on the "Add/Remove Programs" icon, and click on the "Install" button. This Control Panel
applet also lets you uninstall applications currently found on your PC. The dialog box looks like what is
shown below (for Windows XP):
Installing software in this way ensures that if you wish to remove the application at a later time, you will be
able to do so by finding the name of the application in the list and clicking the "Add/Remove" button in this
dialog box. Uninstalling applications by using the Add/Remove Programs dialog box ensures that the
application files are removed from the hard disk, and also that all mentions of the program are removed
from the Windows Registry.
In Windows Vista through Windows 10, you will click on the Start button, then click on Control Panel, and
then click on the link for Uninstall a program. That screen looks like the illustration shown below:
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How to uninstall application software
Uninstalling software should always be done from the "Uninstall a Program" dialog box from within the
Control Panel. The Windows Uninstaller should remove all of an application's program files, all mentions
of the program from the Start menu, and removes all references to the program from the Windows
Registry.
Occasionally, the Windows Uninstaller does less than a complete job of removing a program from your
system. If you find that the Windows Uninstaller does not properly uninstall an application from your
system, a third-party program like Revo Uninstaller does an excellent job of removing an application from
the computer. The Revo Uninstaller scans through the Registry, so it knows what to remove and how to
return your system to the state it was in before the application was installed. You can obtain the free
version of the Revo Uninstaller from the link shown below:
http://www.revouninstaller.com/revo_uninstaller_free_download.html
Troubleshooting application software problems
There are as many problems involved with software usage as there are software programs available on
the market today. This particular segment of the course will not attempt to solve every possible software
problem you might encounter as a technician ... no technical manual ever could. However, this section of
the course will cover how to trouble-shoot application software-related problems of the kinds found in the
text below.
Bad installation programs
Not every software installation program does a perfect job of putting a new application on your PC. In fact,
some installers are downright treacherous. A good installation program should do the following things:
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Create a temporary directory that will be used for the software installation, and then delete the
directory from the disk when the installation is completed.
Check to make sure that it is not overwriting newer files with older ones, thus potentially corrupting
the entire system (a warning message should appear if this issue arises).
Check to be sure that you really want to reinstall the software if the program currently exists on the
hard disk.
Backup the system Registry files to make sure that if something does go wrong, the damage can
be undone quickly and easily.
Load an uninstaller on the PC for that application, so that the program can be smoothly removed
if necessary.
If an install program doesn't do all these things, then there is a serious possibility that your install program
could create a problem on your PC while installing the software. You should read the documentation for
the install program before attempting to do the software installation, and try the installer on a
non-production PC if you have any serious questions. Also, a good backup of the system may be in order
if you are not sure of the quality of the software or install program.
As a rule (and for the A+ examination), you should always install new software onto a PC from the
"Uninstall a Program" icon in Windows. Installing software this way ensures that you have the ability to
uninstall the product if something should go wrong with your PC after your new software is installed. Note
that in Windows XP, you will click on Start, then Settings, Control Panel, Add/Remove Programs, then
Add New Programs, give the name and location of the install program and press Enter. Follow the
directions on the screen to install the program correctly.
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To uninstall the program, simply return to the Uninstall a Program icon, select the name of the program
you wish to uninstall, and click the "Remove" button. The Windows uninstaller will take care of the rest for
you, returning the Windows Registry to the state it was in before the software was installed, and
removing all related files from your hard disk.
Service packs from Microsoft
Instead of issuing revised versions of Windows (or other application programs), Microsoft made available
to the customer via their web site programs called service packs, which when run will update Windows
with revised versions of specific files that have had reported problems.
These service packs are available from Microsoft at no charge for Windows XP, Vista, Windows 7,
Windows 8, and for the Microsoft Office 2010/2013/2016 suites. Service packs for older operating
systems and application suites are still available on the Internet, but Microsoft no longer makes these
resources available on their website.
These service packs are self-extracting archive files that will automatically unpack and then install the
proper components on your PC. If you encounter unusual problems on your PC, it is possible that running
a service pack upgrade may fix the problem.
Visit the Microsoft Download web site at http://www.microsoft.com/download for more details.
Conflicting DLL file versions, and 16-bit vs. 32-bit DLLs
.DLL files are Dynamic Link Libraries, that contain much of the program code that makes a Windows
application work. Each version of Windows came out with its own set of .DLL files. If you accidentally
replace a newer Windows .DLL file with one from a previous Windows version, Windows AND the
application you just installed will both fail to operate.
As a preventative measure, you may want to store somewhere a copy of all of the proper .DLL files for
your version of Windows (and applications) in a safe place, just in case something happens to replace
one of your .DLL files by accident. Also, the Microsoft System File Checker (SFC) utility is provided to
help you reinstall key system files and .DLL files from the Windows operating system install disks.
You may also find that within a Windows version, there may have been some updating of .DLL files by
Microsoft (or other software vendors) without your knowledge. The general rule is that it is always best to
use the most up-to-date version of a .DLL file, unless you know that some kind of software conflict is
taking place that would move you to replace a newer file with an older one.
Technical support representatives from different companies may instruct you from time to time to replace
such files if an application is malfunctioning. Also, service packs and patches will update critical .DLL
files, sometimes fixing the problem, and sometimes creating more of a problem. Be sure to contact the
software manufacturer for assistance if you encounter such problems.
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User error
User error is probably the most common reason for computer or application software failure. If a person
does not know "the rules of the road" concerning how to use a computer or a typical Windows application,
more than likely they will do something destructive to the computer without knowing that they did it, or
meaning to do so in the first place. Some of the more common mistakes that users will make include:
o
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o
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o
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not saving their work regularly
not backing up their work on a regular basis
saving files to the hard disk instead of a floppy disk, or vice versa
forgetting the location of a file, or the name of a file
forgetting your password
using the same name for two different files, overwriting one with another
overwriting good files with bad / blank ones
deleting files / icons unintentionally
launching more than one instance of a program, because of impatience with the computer
printing to a turned-off (or off-line) printer, or to the wrong printer port
not knowing how to use the "undo" feature in Windows applications
not having an anti-virus program on your computer
randomly hitting buttons or keys while the computer is processing some information
pressing the reset key while the hard disk is writing data to the disk
failing to read the instructions that appear on the screen
failing to read the manual
having a general paranoia of the computer
As a technician, you have the power to fix (or at least determine) the nature of the user error. Your most
important task, however, is to ensure that the user learns from their experience, and does not repeat the
same mistake again. You should have available a number of reference works you can suggest that will
help the user to get up the learning curve concerning the use of a computer product.
You should also know of several places where a novice computer user can go to get the training they
need to become more skilled in the computing arts. Many local community colleges provide excellent
computer courses at a reasonable cost. Always recommend to users that they take time for training in
computer use and the specific software applications they use regularly.
The price of one class can be much less costly than several repeat repair calls on your part, and more
satisfying to the user than just fixing repeated problems.
NOTES
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Operating System Installation and Upgrade Paths
There are a number of ways a technician can install (or upgrade) a Windows-based operating system.
The descriptions below include the methods covered on the A+ examination.
Clean installation
A clean installation of Windows (or any other operating system) assumes that the customer has a blank
hard drive with no operating system on it, or that the customer wishes to wipe out the existing installation
and start from scratch. A customer or technician may choose to do a “wipe-and-reload” clean installation
of the operating system if the computer has been seriously compromised by viruses or malicious
software. In those kinds of situations, care must be taken when attempting to backup any customer data.
If any of the customer’s files have been corrupted with a virus or malware, those files must be cleaned
with some kind of anti-virus/anti-malware solution before introducing the data back onto the hard drive.
A clean install version of the Windows disc must be used to perform such an installation; an upgrade
version of the installation disc will not perform a clean install. If the computer was made by a major
manufacturer (Dell, for example), a Dell version of the installation disc will restore the operating system
AND ensure the copy of Windows is activated properly. However, you can use a Dell installation disc
ONLY on a Dell computer. The installation script on the disc will run a program to determine if the
computer was indeed made by that manufacturer. If the computer is made by some other manufacturer,
the Windows version will not be installed or activated properly.
Many manufacturers (HP, Toshiba, Acer) use a specific product recovery disc to install Windows on a
computer. These product recovery discs are made to work only with specific models of PCs and laptops;
they cannot be used interchangeably between different models of the same manufacturer. However,
these discs contain all of the necessary driver software and pre-installed applications from the
manufacturer, and will bring the computer back to the “out-of-box” state, where the computer is just like
brand new again. If the customer does not have the product recovery discs, they can be ordered from
the manufacturer, typically for only the cost of shipping and handling (less than $20.00).
Some manufacturers provide a “recovery partition” on their hard drives. These partitions will allow for a
reinstallation of the operating system, back to the “out-of-box” state, and will also allow the customer to
create their own product recovery discs as well. HP, Lenovo, and other manufacturers typically put
recovery partitions onto their products. Pressing the F11 key during system start-up will cause the
computer to boot to the recovery partition, instead of the normal boot partition, and the product recovery
program will launch. Follow the prompts to complete the process.
If the customer built their own PC, they will use an original equipment manufacturer (OEM) version of the
Windows installation disc. However, they will need to use the 25-character code found on the Certificate
of Authenticity (COA) to install the operating system, and then the customer (or technician) will need to
activate the Windows version online, or by phone.
If Microsoft indicates that the license of Windows has already been installed on another PC, the
customer or technician needs to discuss the matter with staff at the Microsoft contact center. If the copy
of Windows is being re-installed because a hard drive failed or because the system needed to be wiped
and re-loaded, explaining this to Microsoft will usually result in a successful re-activation of the operating
system. Otherwise, the customer will be told that they need to purchase another license of the operating
system. Except for Enterprise versions of the operating system, Windows can legally be installed only on
one (1) computer at a time.
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Multi-boot installation
Multi-booting is the act of installing multiple operating systems on a computer, and then choosing which
one to boot and use. The term dual-booting refers to the common configuration of specifically two
operating systems. Multi-booting may require a custom boot loader. The Linux boot loader called GRUB
supports multi-booting on the same PC. Windows does support booting to multiple Microsoft operating
systems only.
When multi-booting different Microsoft operating systems, the “older” operating system should be
installed first. For example: if one wanted to boot to either Windows XP or Windows 7 on the same PC,
Windows XP should be installed first, and then Windows 7. If this was reversed, the Windows XP
installation disc would not understand the existing Windows 7 installation. Once both Microsoft operating
systems are installed properly, the file called boot.ini will cause a menu to be displayed for 30 seconds at
boot-up time. This menu will allow the customer to select which operating system to use; if no choice is
selected, a default choice will boot and run one of the two installed operating systems.
When installing a Linux operating system on a PC that already has Windows, the installation script will
ask the customer if they wish to keep Windows, or wipe it out and replace it. If the customer decides to
keep Windows on the system, GRUB will enable the user to select to boot either to Linux or Windows. In
fact, GRUB will support booting to more than two operating systems.
Remote network installation with RIS
Remote Installation Services (RIS) is a Microsoft-supplied utility that allows PXE BIOS-enabled
computers to remotely execute boot environment variables, such as the installation of an operating
system. Short for Pre-Boot Execution Environment, PXE allows a workstation to boot from a server on a
network prior to booting the operating system on the local hard drive.
RIS is used to create installation images of operating systems or computer configurations, which can be
used to facilitate the installation process to users whose machines have been granted access to the RIS
server. This eliminates the need to use a CD-ROM for installing an operating system. This is one of
several ways that a standard desktop operating system image can be deployed to many computers at
the same time within an organization.
Here is how a remote network operating system installation takes place:
At boot time, a workstation that has been set to boot from PXE (to the network card, rather than to the
hard drive) will issue what is called a BOOTP request via the network. Once the request is received, the
DHCP Server will supply an IP address to the computer, and the DNS server will point the client
computer to the RIS server, which in turn will issue a disc boot image (often called the "OS Chooser").
Once the OS Chooser environment has been booted, the user must authenticate against the Domain
Controller (with a username and password), and can then select a Windows image to install. The source
files for each image can be customized to slipstream updates and service packs, apply tweaks, perform
unattended installations, and include software with the operating system. RIS can be used only for clean
installations and cannot be used to upgrade a previous version of Windows.
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Repair installation
From time to time, Windows can become slow or will fail to boot the computer to normal operation. In
such cases, a repair installation should be performed first, before attempting to wipe the drive and
reinstall Windows from scratch. By installing the Windows installation disc and booting to the DVD drive,
the customer or technician can select the option to “Repair My Computer”.
A script that runs on the installation disc will inspect the existing Windows installation for problems, and
will attempt to resolve any identified problems. The program may replace certain operating system files
that may have been corrupted, and may also correct any problems with the boot files. If successful, the
repair installation will being the operating system back to normal, and all programs and data files will be
unaffected.
However, if the repair installation fails to identify or correct the problems, wiping and re-installing the
operating system may be the only alternative. Customer files must be backed up (if possible) before
wiping and reinstalling the operating system, and any recovered customer files must be scanned for
viruses and malware before being returned to the hard drive.
Unattended installation
An unattended installation is a scripted operating system installation that runs Windows Setup locally on
the device using something called an “answer file.” The solution provides sample scripts that perform the
preparation steps and operating system deployment. The process differs from the more typical networkbased installations because the operating system installation files are delivered within an image instead
of the using a CD or network shared folder.
An unattended installation is a two-phase process. In the first phase, operating system files and boot
instruction are added to the controller. A batch file called PrepImage.bat is run and populates a partition
with Windows installation and bootstrap files. The batch file then captures an image of the partition.
In the second phase, the image is deployed by running an Automated Deployment Service (ADS) task
sequence on a device connected to the controller and using the Deployment Agent. During the
sequence, the device that receives the image uses the bootstrap and installation files to run Windows
Setup locally without intervention from an administrator or technician. Device variables are used during
the sequence to personalize the installation (for example, to set the computer name).
There are several advantages to choosing an unattended installation.
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Hardware components can differ for target devices - With an unattended installation, the ADS
Controller deploys setup files to a device and the Windows setup process then runs locally on the
device. During the setup process, hardware detection occurs. Any Windows-supported hardware
will be installed and configured. However, deployment of a fully configured Windows operating
system image to a device lacks this hardware flexibility. Devices receiving the image must
essentially have the same hardware configuration as the server on which the master image was
created.
Multicast support - The files needed for Windows setup, along with bootstrap files, are delivered
to the target devices as an ADS image. By using an image, you can simultaneously deploy the
unattended installation process to devices without impacting the network to the degree that a
traditional, mapped drive would. Unattended installations of operating systems can occur to
potentially hundreds of devices at the same time, a significant improvement over traditional,
network-based, unattended installations.
Slipstream service packs and security updates - In an unattended operating system installation,
the i386 directory can be updated with the most current service packs and security updates.
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One drawback to an unattended installation is that each device takes approximately 30 to 40 minutes to
run Windows Setup. In contrast, when an image configured with Sysprep (a utility that individualizes
each PC after being imaged) is deployed to a target device using the typical ADS methods, it takes
about 12 to 20 minutes to install a fully configured Windows operating system.
In addition, the device in a typical deployment may also receive configured applications along with a fully
installed Windows operating system. With an unattended installation, application installation must be
scripted.
Upgrade installation
Upgrading to a newer Windows version when you already have a version of Windows installed on your
computer allows you to keep your files, settings, and programs. In order to do this, you need to have an
upgrade version of the operating system installation disc. The “clean install” version of the disc typically
will not support an upgrade of an existing Windows installation. Inspect the installation disc you are using
before attempting to perform an upgrade.
NOTES
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Different kinds of installation media
An operating system typically is installed using a DVD disc provided by the hardware manufacturer or by
Microsoft. However, this disc media can be replicated onto a USB flash drive, an SSD or traditional hard
drive, from another partition on an installed hard drive, or via the network using PXE booting. This gives
the technician additional options for performing an operating system installation.
Disk Partitioning
When an operating system is installed, or when a disk is formatted, the disk media needs to be
partitioned properly. The disk partition table tells the operating system how large the disk is, and how it
has been divided, even is the disk is one single partition. One single hard drive (or other kinds of disk
media) can be split into several logical disk partitions, and the partition sizes can be selected by the
customer. Typically, customers make a single partition on a single disk drive; it’s just simpler that way.
There are several kinds of partitions that can be created on hard disk drives:
Basic partitions
Most personal computers are configured as basic disks, which are the simplest to manage.
A basic disk uses primary partitions, extended partitions, and logical drives to organize data. A formatted
partition is also called a volume (the terms volume and partition are often used interchangeably). In a
Windows environment, basic disks can have either four primary partitions or three primary and one
extended partition. The extended partition can contain multiple logical drives (up to 128 logical drives are
supported). The partitions on a basic disk cannot share or split data with other partitions. Each partition
on a basic disk is a separate entity on the disk.
Dynamic partitions / disks
Advanced users and IT professionals can make use of dynamic disks, which use multiple hard disks
within a computer to manage data, usually for increased performance or reliability.
Dynamic disks can contain a large number of dynamic volumes (approximately 2000) that function like
the primary partitions used on basic disks. In some versions of Windows, you can combine separate
dynamic hard disks into a single dynamic volume (called spanning), split data among several hard disks
(called striping) for increased performance, or duplicate data among several hard disks (called mirroring)
for increased reliability.
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Primary partitions
A primary partition is the hard disk partition where both Windows OS and user data can reside, and it is
the only partition that can be set active. In addition, only one primary partition on one hard disk can be
set as active to boot operating system at a time.
Extended partitions
An extended partition is a container that can hold one or more logical drives. Logical drives function like
primary partitions except that they cannot be used to start an operating system. A hard disk needs to be
partitioned and formatted before you can store data on it.
Logical partitions
A logical partition, commonly called an LPAR, is a subset of computer's hardware resources, virtualized
as a separate computer. In effect, a physical machine can be partitioned into multiple logical partitions,
each hosting a separate operating system.
GPT partitions
A Globally Unique Identifier (GUID) Partition Table (GPT) is a partitioning scheme that is part of the
Unified Extensible Firmware Interface specification; it uses a globally unique identifier for qualifying
devices. It is the next generation partitioning scheme designed to succeed the Master Boot Record
partitioning scheme method.
Although it forms a part of the Unified Extensible Firmware Interface (UEFI) standard (the Unified EFI
Forum which is a replacement for the traditional PC BIOS), it is also used on some BIOS systems
because of the limitations of master boot record (MBR) partition tables, which use 32 bits for storing
logical block addresses (LBA) and size information on a traditionally 512 byte disk sector.
File system types and disk formatting
Once a disk is partitioned, it must be formatted so that the operating system can read and write data to
the disk in a logical and coordinated fashion. A quick format simply creates the file allocation table (FAT)
for the disk, and verifies the beginning and ending markers for the partition. A full format also verifies all
sectors on the disk during the formatting process. Full formats of large disks can take 20 to 40 minutes to
complete, while a quick format of even a huge disk can be completed in less than one minute.
Below is a list of the various kinds of disk format types covered on the A+ examination.
Windows-supported format types
ExFAT
exFAT (Extended File Allocation Table) is a Microsoft file system that is optimized for flash drives. It is
proprietary and Microsoft owns patents on several elements of its design. exFAT can be used where the
NTFS file system is not a feasible solution (due to data structure overhead), yet the file size limit of the
standard FAT32 file system is unacceptable. exFAT also has been adopted by the SD Card Association
as the default file system for SDXC cards larger than 32 GB.
FAT12
This formatting style is used primarily with 5.25-inch and 3.5-inch floppy disks, which now are obsolete.
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FAT32
FAT32 is an older file system that was introduced with the Windows 95 OSR2 version. The boot sector
uses a 32-bit field for the sector count, limiting the FAT32 volume size to 2 TB for a sector size of 512
bytes and 16 TB for a sector size of 4,096 bytes.
The maximum possible size for a file on a FAT32 volume is 4 GB minus 1 byte or 4,294,967,295 (232 −
1) bytes. This limit is a consequence of the file length entry in the directory table and would also affect
huge FAT16 partitions with a sufficient sector size. Large video files, DVD images and databases can
easily exceed this limit.
The design of the FAT32 file system does not include direct built-in support for long filenames, but
FAT32 volumes can optionally hold VFAT long filenames in addition to short filenames in exactly the
same way as VFAT long filenames have been optionally implemented for older FAT12 and FAT16-style
volumes.
Note that older FAT12 and FAT16 file system types are NOT covered on the A+ examination.
NTFS
The NTFS (New Technology File System) is a proprietary file system developed by Microsoft. Starting
with Windows NT 3.1, it is the default file system for all Windows operating systems.
NTFS has several technical improvements over FAT and HPFS (High Performance File System), the file
systems that it superseded, such as improved support for metadata, and the use of advanced data
structures to improve performance, reliability, and disk space utilization, plus additional extensions, such
as security access control lists (ACL) and file system journaling.
NTFS volumes include features such as sparse file support, disk usage quotas, reparse points,
distributed link tracking, and file-level encryption, also known as the Encrypting File System (EFS).
CDFS
This file system type is used on CDs, DVDs and Blu-Ray discs.
Linux-supported format types
While Linux supports all Microsoft Windows-based format types, it also supports several disk format
types as well. Here are some of the main format types you will need to know about for the A+
examination:
ext3
ext3, or the third extended filesystem, is a journaled file system that is commonly used by the Linux
kernel. It is the default file system for many popular Linux distributions. The filesystem was merged with
the mainline Linux kernel in November 2001 from 2.4.15 onward. Its main advantage over ext2 is
journaling, which improves reliability and eliminates the need to check the file system after an unclean
shutdown.
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ext4
The ext4, or the fourth extended filesystem is a journaling file system for Linux, developed as the
successor to ext3. The ext4 filesystem is backwardly compatible with the ext2 and ext3 file systems, and
it can support volumes with sizes up to 1 exbibyte (EiB) and files with sizes up to 16 tebibytes (TiB).
NFS
The Network File System (NFS) is a distributed file system protocol originally developed by Sun
Microsystems in 1984, allowing a user on a client computer to access files over a computer network
much like local storage is accessed. It should not be confused, however, with Microsoft’s NTFS.
NFS, like many other protocols, builds on the Open Network Computing Remote Procedure Call (ONC
RPC) system. The NFS is an open standard defined in Request for Comments (RFC), allowing anyone
to implement the protocol.
NOTES
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Chapter 13. Viruses, Spyware / Malware, Encryption and Data Security
Over the years, computers have been plagued by many different kinds of malicious software that
attaches to a PC and wreaks various kinds of havoc. In the early days of computing, viruses were the
primary way to corrupt a PC or laptop. But with the advent of the Internet, unscrupulous individuals have
developed different kinds of malware that is delivered primarily through email or an Internet connection.
These malicious programs can slow down your computer, redirect your browser to unwanted websites,
capture every keystroke you type, or even corrupt the files on your PC and then demand a ransom in
order to bring things back to normal. Websites masquerading as legitimate well-known companies can
trick users into giving up usernames and passwords, which then are used by hackers to access the
genuine websites and access account information.
To make things worse, many applications designed to protect customers from viruses and malicious
software do not perform as expected. These applications slow down your computer, fail to detect and
remove the malicious software, and require the customer to continue paying year after year for these
under-performing programs.
In this chapter, we will cover the different kinds of malicious software present in the world today. We also
will discuss how hackers are building an infrastructure of sham websites that are designed to trick users
and defraud them in different ways. We also will discuss how nation-states are using military-grade
malicious software and viruses to achieve political goals.
What exactly is a computer virus?
A computer virus is an autonomous executable program that attacks key components of your operating
system, application programs and/or data files. These programs employ "stealth" capabilities so that
you may be unaware that you have a virus, are passing the virus to someone else, or are about to lose
critical data from your hard drive or floppy disks. Once a virus is introduced into the wild, it will spread and
replicate, but it will not “phone home”; that is, it will not coordinate with the virus creator, like malware does.
Almost all viruses are attached to an executable file of some kind. This means the virus may exist on a
system, but it will not be active or able to spread until a user runs or opens the malicious host file or
program, or until a specific set of conditions exist that trigger the program into action. When the host
code is executed, the viral code is executed as well. Normally, the host program keeps functioning
after it is infected by the virus, but it will exhibit unusual behavior.
However, some viruses overwrite other programs with copies of themselves, which destroys the host
program altogether. Viruses spread when the software or document they are attached to is transferred
from one computer to another using the network, a disk, file sharing, or infected e-mail attachments.
Even shrink-wrapped software from the factory can have viruses upon them, and history has proven this
fact out many times. Any disk that touches your computer, even a CD-ROM disk, may potentially have a
virus upon it, so you must treat every disk you touch as suspect, and run a virus scan upon each disk
BEFORE running any programs on it or viewing any documents upon it.
Nowadays, viruses comprise a much smaller percentage of the total number of software threats in the
world today. Only 10 to 15 percent of the computers affected by malicious software actually have what
is considered to be a true “virus.” Nevertheless, you need to know the differences between viruses and
malware, and what each kind of threat does to wreck your computer.
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How do viruses affect your PC?
Viruses will affect your PC in several different ways . . .
1) The boot sector:
The boot sector is where your operating system files reside
on your floppy or hard disk. A virus will go to that location on
your disk and corrupt these files (NTLDR, or
NTDETECT.COM) so that your PC will NOT boot up as
expected. EXAMPLE: the STONED virus.
2) The File Allocation Table:
The File Allocation Table (FAT) is a list of all the files on your
floppy or hard disk, and where the files are physically
located on the disk. A virus will corrupt the FAT so that you
cannot locate or access your files.
EXAMPLE: the CASCADE virus.
3) The partition table:
The partition table on your HARD DISK tells the operating
system how big your hard disk is, and what percentage of it
is used by the O/S. A virus can corrupt your partition table,
which wipes out ALL of your files in an instant.
EXAMPLE: the MICHELANGELO virus.
4) .COM and .EXE files:
Files with these extensions are EXECUTABLE files, which
perform a specific action. A virus can attach itself to one of
these kinds of files and corrupt the way it operates. These
same kinds of viruses can infect .OVL or overlay files, which
work along with .COM and .EXE files.
EXAMPLE: the JERUSALEM virus.
5) Macro viruses:
A macro virus will execute a set of instructions that have a
destructive effect on your Windows registry, configuration
files, or your data files. These viruses can be transmitted
when you receive data files from someone else's computer
(like a resume file or a spreadsheet), or they can be
transmitted by e-mail messages.
EXAMPLE: the WM-CONCEPT virus.
E-mail viruses act much like macro viruses, but are
transmitted to you by e-mail as an "attachment" (a
secondary message sent to you along with the main email message). Many e-mail viruses are classified as
"Trojan horses" since they appear to be normal kinds of
messages but they carry a destructive payload.
EXAMPLE: the ILOVEYOU virus.
6) E-Mail viruses:
7) Logic bombs:
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Logic bombs include a timing device so they will go off at
a particular date and time, or when a particular system
event takes place (like formatting a floppy disk or
performing a scan of your hard disk).
EXAMPLE: the FRIDAYTHE13TH virus.
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8) Trojan Horse programs:
A Trojan horse is a non-self-replicating type of malware
which appears to perform a desirable function but
instead drops a malicious payload, often including a
backdoor allowing unauthorized access to the target's
computer.
The term is derived from the story in Greek mythology
because Trojan horses employ a form of “social
engineering,” presenting themselves as harmless or
useful gifts, in order to persuade victims to install them
on their computers.
EXAMPLE: the Melissa virus
9) Joke programs:
A joke program does something to change or mess up
the appearance of information on your screen, or affect
adversely the operation of your computer. Joke
programs are not destructive, and are usually intended
as a prank or a practical joke.
EXAMPLE: the JAN12000 virus.
10) Polymorphic viruses:
A polymorphic virus may take any of the forms listed
above,but the virus will mutate into different forms upon
every new PC on which the virus infects. It does this in
order to evade detection and being destroyed by an
anti-virus program.
EXAMPLE: the SATAN BUG virus.
The website called archive.org has a “museum” of different kinds of malicious software and viruses that
you can look at safely, without concern for infecting your computer. Below is a link to that website:
https://archive.org/details/malwaremuseum?sort=-publicdate
For the A+ examination, you will need to be able to answer the following kinds of questions:


What is a computer virus, and how can it be transmitted?
What are the major types of viruses, and how do they affect your computer?
Three things a good virus protection program should do
A virus program that is worth anything should be able to do the following three things reliably:
1)
SCAN for viruses: A good program should be able to check your floppy and hard disks for
viruses, as well as the RAM of your computer, and detect the presence of a virus in the
locations and ways mentioned above.
2)
CLEAN up the virus: A good program must be able to get rid of the virus it finds in any of
these places mentioned above; otherwise, it's useless.
3)
PROTECT YOU from viruses: A good program must have the ability to load a piece of the
program into memory at boot-up time, to protect you from getting a virus in the first place.
This type of program is called a "Terminate-and-Stay-Resident" (TSR) program. This
program will scan all files being accessed from disk or loaded into memory; if it finds a virus, it
will alert you and clean it up.
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An example of a good anti-virus program is AVG Free Antivirus. This freeware program is available from
the instructor's course DVD, and also online. It has the ability to be updated periodically, so that the
programs will detect and protect you from all the newest strains of viruses. These updates are called
"signature files" or "definition files", and they contain a database of information that the antivirus program
uses to detect and eliminate viruses from your PC.
You should update your signature files at least once a month, for maximum protection. If you have a
broadband Internet connection, you should update your anti-virus application as frequently as possible.
The application likely will update automatically, unless you indicate not to do so when installing the
program.
Programs like Symantec / Norton Antivirus and McAfee Internet Security are costly, use a lot of system
overhead to operate, require an annual service fee to continue getting signature file updates, and they
miss many common viruses. Also, companies like Verizon and Comcast provide anti-virus and Internet
security software to their customers for a monthly service charge; most of these applications are
ineffective and not worth the cost.
IF you must use one of these programs, make sure the application is continually kept up-to-date. The
author does NOT recommend the use of Symantec / Norton Antivirus or McAfee Internet Security; these
underperforming applications compromise system security, rather than enhancing it.
For the A+ examination, you will need to be able to answer the following kinds of questions:



What three things should a good virus protection product do?
What is a "signature file", and what does it do for the antivirus program?
How often should you update your signature files for your antivirus product?
What is spyware/malware and adware?
Spyware (also called malware) refers to any software that covertly gathers user information through the
user's Internet connection without his or her knowledge, usually for advertising purposes. Spyware
applications are typically bundled as a hidden component of freeware or shareware programs that can be
downloaded from the Internet; however, it should be noted that the majority of shareware and freeware
applications do not come with spyware.
Once installed, the spyware monitors user activity on the Internet and transmits that information in the
background to someone else. Spyware can also gather information about e-mail addresses and even
passwords and credit card numbers.
Spyware is similar to a Trojan horse in that users unwittingly install the product when they install
something else. A common way to become a victim of spyware is to download certain peer-to-peer file
swapping products that are available today.
Aside from the questions of ethics and privacy, spyware steals from the user by using the computer's
memory resources and also by eating bandwidth as it sends information back to the spyware's home
base via the user's Internet connection. Because spyware is using memory and system resources, the
applications running in the background can lead to system crashes or general system instability.
Because spyware exists as independent executable programs, they have the ability to monitor
keystrokes, scan files on the hard drive, snoop other applications, such as chat programs or word
processors, install other spyware programs, read cookies, change the default home page on the Web
browser, consistently relaying this information back to the spyware author who will either use it for
advertising/marketing purposes or sell the information to another party.
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Licensing agreements that accompany software downloads sometimes warn the user that a spyware
program will be installed along with the requested software, but the licensing agreements may not always
be read completely because the notice of a spyware installation is often couched in obtuse, hard-to-read
legal disclaimers.
Adware
Adware is a form of spyware that collects information about the user in order to display advertisements in
the Web browser based on the information it collects from the user's browsing patterns.
Adware is considered a legitimate alternative offered to consumers who do not wish to pay for software.
Programs, games or utilities can be designed and distributed as freeware. Sometimes freeware blocks
features and functions of the software until you pay to register it. Today we have a growing number of
software developers who offer their goods as "sponsored" freeware until you pay to register. Generally
most or all features of the freeware are enabled but you will be viewing sponsored advertisements while
the software is being used. The advertisements usually run in a small section of the software interface or
as a pop-up ad box on your desktop. When you stop running the software, the ads should disappear. This
allows consumers to try the software before they buy and you always have the option of disabling the ads
by purchasing a registration key.
In many cases, adware is a legitimate revenue source for companies who offer their software free to
users. A perfect example of this would be the popular e-mail program, Eudora. You can choose to
purchase Eudora or run the software in sponsored mode. In sponsored mode Eudora will display an ad
window in the program and up to three sponsored toolbar links.
Eudora adware is not malicious; it reportedly does not track your habits or provide information about you
to a third party. This type of adware is simply serving up random paid ads within the program. When you
quit the program the ads will stop running on your system.
Backdoors
A backdoor is a method of bypassing normal authentication procedures, usually over a connection to a
network such as the Internet. Once a system has been compromised, one or more backdoors may be
installed in order to allow access in the future, invisibly to the user. The idea has often been suggested
that some computer manufacturers preinstall backdoors on their systems to provide technical support
for customers. Backdoors may be installed by Trojan horses, worms, implants, or other methods.
Bots and Worms
The term "bot" is derived from the word "robot" and is an automated process that interacts with other
network services. Bots often automate tasks and provide information or services that would otherwise
be conducted by a human being. A typical use of bots is to gather information (such as web crawlers),
or interact automatically with instant messaging (IM), Internet Relay Chat (IRC), or other web
interfaces. They may also be used to interact dynamically with websites.
Bots can be used for either good or malicious intent. A malicious bot is self-propagating malware
designed to infect a host and connect back to a central server or servers that act as a command and
control (C&C) center for an entire network of compromised devices, or "botnet." With a botnet,
attackers can launch broad-based, "remote-control," flood-type attacks against their target(s). In
addition to the worm-like ability to self-propagate, bots can include the ability to log keystrokes, gather
passwords, capture and analyze packets, gather financial information, launch denial-of-service (DoS)
attacks, relay spam, and open back doors on the infected host.
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Bots have all the advantages of worms, but are generally much more versatile in their infection vector,
and are often modified within hours of publication of a new exploit. They have been known to exploit
back doors opened by worms and viruses, which allows them to access networks that have good
perimeter control. Bots rarely announce their presence with high scan rates, which damage network
infrastructure; instead they infect networks in a way that escapes immediate notice.
Computer worms are similar to viruses in that they replicate functional copies of themselves and can
cause the same type of damage. In contrast to viruses, which require the spreading of an infected host
file, worms are standalone software and do not require a host program or human help to propagate. To
spread, worms either exploit a vulnerability on the target system or use some kind of social
engineering to trick users into executing them.
A worm enters a computer through a vulnerability in the system and takes advantage of file-transport
or information-transport features on the system, allowing it to travel unaided.
Exploits
An exploit is a piece of software, a command, or a methodology that attacks a particular security
vulnerability. Exploits are not always malicious in intent—they are sometimes used only as a way of
demonstrating that a vulnerability exists. However, they are a common component of malware.
Grayware
Grayware is a general term sometimes used as a classification for applications that behave in a manner
that is annoying or undesirable, and yet less serious or troublesome than malware. Grayware
encompasses spyware, adware, dialers, joke programs, remote access tools, and any other unwelcome
files and programs apart from viruses designed to harm the performance of computers on your network.
Grayware refers to applications or files that are not classified as viruses or Trojan horse programs, but
can still negatively affect the performance of the computers on your network and introduce significant
security risks to your organization. Often kinds of grayware perform a variety of undesired actions such as
irritating users with pop-up windows, tracking user habits and unnecessarily exposing computer
vulnerabilities to attack.
Nation-state or military-grade malware
Malware is typically used for criminal purposes, but it also can be used for sabotage, often without
direct benefit to the perpetrators. One example of sabotage was the Stuxnet “virus”, used to destroy
very specific industrial equipment. There have been politically motivated attacks that have spread over
and shut down large computer networks, including massive deletion of files and corruption of master
boot records, described as "computer killing".
Some of these malware attacks can be traced to governments, nation-states, and their national
security and defense departments, despite the fact that these countries and agencies vigorously deny
perpetrating such activities. If a computer becomes infected with military-grade malware, little or
nothing can be done to salvage it.
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Ransomware
Ransomware is a type of malware that prevents or limits users from accessing their system. This type
of malware forces its victims to pay the ransom through certain online payment methods in order to
grant access to their systems, or to get their data back. Some ransomware encrypts files; the
Cryptolocker ransomware is perhaps the best-known example. Other kinds of ransomware use TOR
(the onion network) to hide command and control (C&C) communications; CTB Locker is one example.
The ransom prices vary, ranging from $USD 24 to more than $USD 600, or even its bitcoin equivalent.
It is important to note, however, that paying for the ransom does not guarantee that users can
eventually access the infected system.
Users may encounter this threat through a variety of means. Ransomware can be downloaded by
unwitting users by visiting malicious or compromised websites. It can also arrive as a payload, either
dropped or downloaded by other malware. Some ransomware are delivered as attachments to
spammed email.
Once executed in the system, a ransomware can either lock the computer screen, or encrypt
predetermined files with a password. In the first scenario, a ransomware shows a full-screen image or
notification, which prevents victims from using their system. This also shows the instructions on how
users can pay for the ransom. The second type of ransomware locks files like documents,
spreadsheets and other important files.
Rootkits
Once a malicious program is installed on a system, it is essential that it stays concealed, to avoid
detection. Software packages known as rootkits allow this concealment, by modifying the host's
operating system so that the malware is hidden from the user. Rootkits can prevent a malicious
process from being visible in the system's list of processes, or keep its files from being read. Some
malicious rootkits also contain routines to defend against removal, not merely to hide themselves.
UEFI BIOS malware
UEFI is a replacement for the traditional BIOS (Basic Input/Output System) and is meant to
standardize modern computer firmware through a reference specification. Multiple companies develop
UEFI firmware, and there are significant differences between the implementations used by PC
manufacturers.
An ethical hacking group recently demonstrated a method for infecting the UEFI firmware. Such
software could remain on the PC even if the hard disk drive if replaced. The malware uses a rootkit
that has three modules: one for reading and writing to NTFS file systems; one for hooking the OS boot
process; and one that checks if remote control system (RCS) is present on the system. Such software
can even write to the ROM chips on a hard disk controller, making it nearly impossible to remove.
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Dealing with malware and spyware
While one may not realize they have installed spyware, there are some signs that it exists on your
computer. If you notice any changes to your Web browser that you did not make such as extra toolbars or
different homepage settings, as well as changes to your security settings and favorites list, you could
have spyware running on your system.
Other signs of a spyware infection include pop-up ads which are not related to a Web site you're viewing;
usually spyware advertisements are adult content in nature and are not displayed in the same fashion as
legitimate ads you would normally see on your favorite Web sites. You may also see advertisements
when you are not browsing the Web. Clicking hyperlinks which do not work (or take you somewhere you
did not expect), a sluggish system, or your system taking longer to load the Windows desktop are all
signs that your computer may be infected with spyware.
With the onset of spyware comes a number of anti-spyware software packages to rid your system of
these unwanted and malicious programs. Anti-spyware software works by identifying any spyware
installed on your system and removing it. Since spyware is installed like any other application on your
system it will leave traces of itself in the system registry and in other places on your computer.
Anti-spyware software will look for evidence of these files and delete them if found.
Reputable and effective anti-spyware applications include programs such as AdAware, Malwarebytes
Anti-Malware, Spybot Search-and-Destroy, and Microsoft’s Windows Defender. You can run one or two
of these programs simultaneously on your PC without any adverse effects upon system performance.
On the other hand, you cannot run more than one anti-virus application on your PC at the same time.
Each anti-virus program will perceive the other anti-virus program as a virus threat, and your system will
slow to a crawl in short order.
It is important to remember that not all companies who claim their software contains adware are really
offering adware. There is always a chance that adware is spyware in disguise so to speak, and that
programs with embedded spyware may not state its existence at all.
Rogue antivirus programs like Antivirus 360 (made to look like Norton 360), Antivirus 2015 and Internet
Security 2015 (made to look like Norton Internet Security 2015) appear to the average user to be
legitimate programs, when in fact they are the worst kind of spyware. They will pester the user until they
pay the $29.00 (or larger) fee over the Internet, only to find that their computer is now totally corrupted
and the money has gone towards illicit activities. Removing these rogue applications is difficult at best; if
left unchecked for more than a few days, they can completely ruin the operating system and user data
on a hard drive.
Always stay on the side of caution and be sure to research privacy policies and licensing agreements that
come with freeware. You should also become familiar with Internet lists of companies reported to be
using spyware. Much like a firewall or anti-virus program, anti-spyware software is crucial to maintain
optimal protection and security on your computer and network.
The instructor’s course DVD has a number of effective anti-spyware applications included on it, so that
you can install them on any PC. These will ensure that any PC you use is free from malware and rogue
software. These programs also are freely available on the Internet, and can be shared without concerns
for software piracy issues.
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Encryption technologies
Encryption is the process of transforming information (referred to as plaintext) using an algorithm (called
cipher) to make it unreadable to anyone except those possessing special knowledge, usually referred to
as a key. The result of the process is encrypted information (in cryptography, referred to as ciphertext). In
many contexts, the word encryption also implicitly refers to the reverse process, decryption (i.e.,
software for encryption can typically also perform decryption), to make the encrypted information readable
again (i.e., to make it unencrypted).
Encryption has long been used by militaries and governments to facilitate secret communication.
Encryption is now commonly used in protecting information within many kinds of civilian systems. In
recent years there have been numerous reports of confidential data such as customers' personal records
being exposed through loss or theft of laptops or backup drives. Encrypting such files helps to protect
them should physical security measures fail. Digital rights management systems which prevent
unauthorized use or reproduction of copyrighted material and protect software against reverse
engineering are another somewhat different example of using encryption on data at rest.
Encryption is also used to protect data in transit, for example data being transferred via networks or the
Internet, in e-commerce systems, mobile telephones, wireless microphones, wireless intercom systems,
Bluetooth devices and bank automatic teller machines. There have been numerous reports of data in
transit being intercepted in recent years. Encrypting data in transit also helps to secure it as it is often
difficult to physically secure all access to networks. Most web browsers support 128-bit encryption when
used on secure HTTP websites for things like e-commerce.
Well-known encryption applications include Pretty Good Privacy (PGP), GPG (GNU Privacy Guard),
TrueCrypt, Secret Agent, and the BitLocker application distributed with Microsoft operating systems.
However, Microsoft’s BitLocker is believed to have a backdoor in it that can be used by agencies of
the United States government; as such, it is not a good choice for secure systems.
Data wiping, hard drive destruction, and hard drive recycling
Simply erasing all the data on your hard drive and formatting it is not sufficient to ensure your files are
totally destroyed. You can spend hours going through your hard drive and deleting all the files and
documents you want, but using the delete key on your keyboard in Windows basically only removes the
shortcuts to the files making them invisible to users. Deleted files still reside on the hard drive and
applications like Recuva (contained on the course DVD) will allow anyone to recover the deleted data.
Formatting the hard drive is a bit more secure than simply erasing the files. Formatting a disk does not
erase the data on the disk, only the address tables. It makes it much more difficult to recover the files.
However a computer specialist would be able to recover most or all the data that was on the disk before
the reformat.
For those who accidentally reformat a hard disk, being able to recover most or all the data that was on the
disk is a good thing. However, if you are preparing a system for retirement to charity or any other
organization, this obviously makes you more vulnerable to data theft.
For some businesses and individual users, a disk format may be something you consider secure enough,
depending, of course, on the type of data and information you saved to your computer. As long as people
understand that formatting is not a 100 percent secure way to completely remove all data from your
computer, then they are able to make the choice between formatting and even more secure methods. If
you have decided a disk format is a good choice, at least to do a full format rather than a quick format.
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Some businesses use electromagnetic degaussing tools to wipe a hard drive and destroy the data on it.
This process also destroys the entire drive and renders it useless. Some companies provide a service
where hard drives literally are shredded with a device that looks like a wood chipper. Some companies
even will take a drill press and drill holes through the drive.
Even more secure than reformatting is a process called disk wiping. The term disk wiping is not only used
in reference to hard drives but any storage device such as CDs, RAIDs, thumb drives and others. Disk
wiping is a secure method of ensuring that all data and software on your computer and storage devices is
irrecoverably deleted before recycling or donating the equipment. Because previously stored data can be
brought back with the right software and applications, the disk wiping process will actually overwrite your
entire hard drive with random data, several times in fact. Once you format you will find it all but impossible
to retrieve the data which was on the drive before the overwrite.
While disk wiping algorithms differ from product to product, they all will generally write the entire disk with
a pattern of random numbers (zero or one). After the wipe is completed, a reformat of the disk is
necessary to reinstall the operating system. The more times the disk is overwritten and formatted the
more secure the disk wipe is, but the trade-off is the extra time to perform additional rewrites. Disk wiping
applications will overwrite the master boot record, partition table, and every sector of the hard drive.
The government standard (DoD 5220.22-M), considered a medium security level, specifies three
iterations to completely overwrite a hard drive six times. Each iteration makes two write-passes over the
entire drive; the first pass inscribes ones (1) over the drive surface and the second inscribes zeros (0)
onto the surface. After the third iteration, a government designated code of 246 is written across the drive,
then it is verified by a final pass that uses a read-verify process.
There are a variety of products available for different operating systems that you can purchase, or freely
downloaded online to perform more secure disk wipes. On the course DVD, the instructor has provided
the disk wiping application called Darik’s Boot and Nuke (DBAN). It will load to a floppy disk, CD or USB
flash drive, and it will perform a military-specification wipe on any type of re-writable data storage device.
Using a hardware and/or software firewall
Firewalls are designed to prevent unauthorized access to or from a private network. Firewalls can be
implemented in both hardware and software, or a combination of both. Firewalls are frequently used to
prevent unauthorized Internet users from accessing private networks connected to the Internet,
especially intranets. All messages entering or leaving the intranet pass through the firewall, which
examines each message and blocks those that do not meet the specified security criteria.
There are several types of firewall techniques:
●
●
●
●
Packet filter: Looks at each packet entering or leaving the network and accepts or rejects it based
on user-defined rules. Packet filtering is fairly effective and transparent to users, but it is difficult to
configure. In addition, it is susceptible to IP spoofing.
Application gateway: Applies security mechanisms to specific applications, such as FTP and
Telnet servers. This is very effective, but can impose a performance degradation.
Circuit-level gateway: Applies security mechanisms when a TCP or UDP connection is
established. Once the connection has been made, packets can flow between the hosts without
further checking.
Proxy server: Intercepts all messages entering and leaving the network. The proxy server
effectively hides the true network addresses.
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In practice, many firewalls use two or more of these techniques in concert. A firewall is considered a first
line of defense in protecting private information. Windows operating systems provide a software firewall
within the standard operating system. Further, commercial and home routers also contain a firewall
application in the device’s firmware. The combination of these two firewalls (PC firewall + router
firewall) in most situations should protect against malicious software infecting a computer.
However, if the customer insists upon practicing “risky behavior” with their PC (downloading suspicious
files, visiting websites with reputations for passing on malware, not maintaining a viable antivirus and
anti-malware application), all bets are off.
Port security
Hardware and software firewalls will allow the customer to control which TCP/IP ports are open or closed.
In TCP/IP and UDP networks, a port is an endpoint to a logical connection and the way a client program
specifies a specific server program on a computer in a network. Some ports have numbers that are
preassigned to them.
Port numbers range from 0 to 65536, but only ports numbers 0 to 1024 are reserved for privileged
services and designated as well-known ports. Knowing the correct port numbers will enable you to
trouble-shoot connection problems or failures, especially if a TCP/IP port has been closed or disabled by
a router. For the A+ examination, you will need to know the port numbers of several protocols in TCP/IP.
Here are some of the commonly-used TCP/IP sub-protocols, and the port assignments they use:
Sub-Protocol
Port Number
AFP:
FTP:
HTTP:
HTTPS:
IMAP:
POP3:
SMTP:
SMB:
TELNET:
548 or 427
20, 21
80
443
143
110
25
137-139, 445
23
By turning on or off specific IP ports, you can permit or prohibit specific kinds of access to your computer
through a firewall application or firewalled router.
Password and authentication technologies
When using a PC and/or logging onto Windows, you will access the computer through a user account that
has a specific username and profile. This allows Windows to be customized for each person that uses the
PC. Along with that username, there is ALWAYS a password with the account, even if the password is
just blank. Passwords can ensure that only the authorized persons can access the data or account on a
PC or network.
If the password is forgotten, the user will not be able to log onto the PC or network, and someone who has
sufficient rights (or proper software application) will have to log on to the computer and reset your
password. Typically, Windows and other secured applications will NOT disclose a forgotten password,
but will allow another user to reset a forgotten password.
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In many government and corporate settings, elaborate password rules are used to ensure that hackers
cannot access sensitive data. Here is an example of how one government agency sets the guidelines for
password complexity:
●
●
●
●
●
●
●
All passwords must be unique (no two people can use the same password)
A password cannot be reused for a year or within the last 16 password changes, whichever is
longer, and passwords must be changed every sixty (60) days
All passwords must be at least 12 characters long
All passwords must contain at least one number and no more than five numbers
All passwords must contain at least one special character and no more than two special
characters (i.e., $, %, !, &, and so forth)
All passwords must contain at least one alphabetic character (which can be uppercase or
lowercase)
All passwords must contain at least six unique characters
Biometrics
In computer security, biometrics refers to authentication techniques that rely on measurable physical
characteristics that can be automatically checked. Instead of using a keyed password, a biometric means
of authentication (such as a fingerprint) can be used instead, as a biometric “password”.
There are several types of biometric identification schemes:
●
●
●
●
●
●
●
●
face: the analysis of facial characteristics
fingerprint: the analysis of an individual’s unique fingerprints
hand geometry: the analysis of the shape of the hand and the length of the fingers
retina: the analysis of the capillary vessels located at the back of the eye
iris: the analysis of the colored ring that surrounds the eye’s pupil
signature: the analysis of the way a person signs his name.
vein: the analysis of pattern of veins in the back if the hand and the wrist
voice: the analysis of the tone, pitch, cadence and frequency of a person’s voice.
Biometrics make for a great password, but once a biometric password is compromised, it is always
compromised. If someone gets a copy of your fingerprint, how are you going to change your fingerprint?
Smart cards
A “smart card” is a small electronic device about the size of a credit card that contains electronic memory,
and possibly an embedded integrated circuit (IC). Smart cards containing an IC are sometimes called
Integrated Circuit Cards (ICCs).
Smart cards are used for a variety of purposes, including:
●
●
●
Storing a patient's medical records
Storing digital cash
Generating network IDs (similar to a token)
To use a smart card, either to pull information from it or add data to it, you need a smart card reader, a
small device into which you insert the smart card. Smart cards are often used in secure installations such
as in the Defense Department or the intelligence agencies to provide a second-level of authentication to a
building location or a computer system.
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Compliance with security regulations
In data storage terminology, the word compliance is used to refer to industry-wide government
regulations and rules that cite how data is managed and the need for organizations to be in compliance
with those regulations. The term encompasses data storage, data archiving, data encryption, and also
data retrieval. Compliance has become a major concern for organizations and businesses, due largely in
part to increasing regulatory requirements which often require organizations to invest in new technologies
in order to address compliance issues.
There are more than 8,500 state and federal regulations concerning records management in the United
States, as well as additional voluntary standards. Some regulatory compliance issues organizations have
to contend with are the Sarbanes-Oxley Act for all public corporations, the Health Insurance Portability
and Accountability Act (HIPAA) for corporations in the healthcare industry, and Securities and Exchange
Commission (SEC) regulations for retention of all electronic correspondence with clients.
Social engineering threats
In the realm of computers, social engineering refers to the act of obtaining or attempting to obtain
otherwise secure data by conning an individual into revealing secure information. Social engineering is
successful because its victims innately want to trust other people and are naturally helpful. The victims of
social engineering are tricked into releasing information that they do not realize will be used to attack a
computer network.
For example, an employee in an enterprise may be tricked into revealing an employee identification
number to someone who is pretending to be someone he trusts or representing someone he trusts. While
that employee number may not seem valuable to the employee, which makes it easier for him to reveal
the information in the first place, the social engineer can use that employee number in conjunction with
other information that has been gathered to get closer to finding a way into the enterprise’s network.
For another example, phishing is a type of security attack that relies on social engineering in that it lures
the victim into revealing information based on the human tendency to believe in the security of a brand
name because they associate the brand name with trustworthiness.
Exploits
Exploits are vulnerabilities in operating systems and/or applications that hackers can use to gain
access to a computer (or network) and exercise control over that system. Exploits are commonly
referred to in terms of how long the general public has known about them (as in the first few days).
For example: a three-day-old exploit is a vulnerability in an operating system or application would be
patched by all the major user groups (individual users, businesses, etc.), but not necessarily by all. A
zero day old exploit is pure gold to a hacker. Nobody knows about it yet, OR nobody has had any time
to work out a patch yet for that vulnerability. A zero-day-old exploit is referred to as a Zero Day Exploit.
Secure Sockets Layer (SSL) and Secure HTTP connections over the Internet
SSL is short for Secure Sockets Layer, a protocol developed by Netscape for transmitting private
documents via the Internet. SSL uses a cryptographic system that uses two keys to encrypt data - a
public key known to everyone and a private or secret key known only to the recipient of the message.
Both Netscape Navigator and Internet Explorer support SSL, and many Web sites use the protocol to
obtain confidential user information, such as credit card numbers. By convention, URLs that require an
SSL connection start with https: instead of http:.
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Another protocol for transmitting data securely over the World Wide Web is Secure HTTP (HTTPS).
Whereas SSL creates a secure connection between a client and a server, over which any amount of data
can be sent securely, HTTPS is designed to transmit individual messages securely. SSL and HTTPS,
therefore, can be seen as complementary rather than competing technologies. Both protocols have been
approved by the Internet Engineering Task Force (IETF) as a standard.
BIOS security on the PC
On a typical PC, there are security features that can be enabled that will protect the computer from
unauthorized use or tampering with the internal components. Many PCs have an intrusion detection
switch that will alert a technician to the fact that someone has opened the case without permission. The
CMOS Setup program can be setup to require a password to enter the setup program itself, and/or to
boot the operating system.
The author strongly recommends against using such BIOS-based password methods. In some cases,
particularly with laptop computers, there is no CMOS or password reset jumper, and removing the CMOS
battery will not remove the password. The user, in such situations, must contact the manufacturer for
assistance in correcting this situation.
Also, any PC or laptop that uses UEFI BIOS should have the flash ROM module write-protected, so that
malicious software cannot over-write the existing BIOS code and corrupt the system. This can be
accomplished by accessing the CMOS Setup program and setting the BIOS to be write-protected. Some
system boards actually have a backup BIOS, to ensure that the computer can recover from a malicious
attack to the ROM.
In addition, users should typically check with the system board manufacturer for any updates to their
UEFI BIOS product, and apply any updates that are available. Such actions can lessen the probability of
a hack attack against the BIOS code.
On the operating system level, Windows allows the user to lock the workstation by pressing
CTRL-ALT-DEL simultaneously, and selecting the Lock Workstation option in the dialog box that appears
on the screen. Pressing CTRL-ALT-DEL again will prompt the user to enter the account password,
thereby unlocking the workstation.
NOTES
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Physical security for networked devices
There are a number of physical security methods that can be used to keep networked devices (and the
information upon them) safe.
Here is a list of topics and terms that are covered on the A+ examination:
Air gap
The process of removing a computer or server from the network by disconnecting the network cable is
called “air gapping” the system. If you believe a computer has been seriously compromised by
malicious software and that the malicious application is spreading to other computers on the network,
air gap the computer immediately.
Then, thoroughly scan the computer with an antivirus/anti-malware application to remove the threat.
You should only reconnect the computer to the network when you are completely sure the threat has
been eliminated.
AUP
Short for Acceptable Use Policy, it is a statement of what the corporate policy is for permitted uses of
computers and networked and Internet-available resources.
Biometrics
Biometrics use physical characteristics that are unique to each person as the basis for a password
criteria. Retinal scans and fingerprints are two such biometrics that can be used for personal
identification and verification.
Brute forcing
Brute force (also known as brute force cracking) is a trial and error method used by application
programs to decode encrypted data such as passwords or Data Encryption Standard (DES) keys,
through exhaustive effort (using brute force) rather than employing intellectual strategies.
BYOD vs. corporate owned equipment
The term BYOD stands for “bring your own device.” Organizations that support the BYOD concept
allow non-agency equipment to connect to the corporate network, in many cases to support teleworking
initiatives. Systems that support BYOD must be tested and hardened to ensure that no rogue
equipment can access privileged information, and that a wide variety of devices (PCs, laptops, tablets,
smartphones) can safely and securely access corporate IT resources.
Many companies, however, do not want to accept the responsibility for supporting IT equipment they
did not purchase. Companies that adopt a “corporate-owned-only” policy for IT systems would lock out
any equipment or devices that are not purchased, authorized or tested by the agency.
Cell tower and wifi signal analyzer
Cell tower and wi-fi signal analyzers allow the customer to locate a desired wireless signal to which
they can connect, and also determine the strength of the signals at the current location. All cell phones
have an indicator that shows how many “bars” you have for a signal from your provider. There are
numerous apps for tablets and smartphones that will analyze both cellular and wi-fi signals.
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Dictionary attacks
A dictionary attack is a method of breaking into a password-protected computer or server by
systematically entering every word in a dictionary as a password. A dictionary attack can also be used
in an attempt to find the key necessary to decrypt an encrypted message or document.
DLP
Data loss prevention (DLP) is a strategy for making sure that end users do not send sensitive or critical
information outside the corporate network. The term is also used to describe software products that
help a network administrator control what data end users can transfer.
A DLP application, for example, could refuse to send an email or detach an attached document if the
application believes that sensitive data that should not be transmitted in contained within the document
or body of the email message.
DRM
DRM stands for digital rights management. Many copyrighted files (such as music or video files) were
purchased by a customer, and the performer of the music or video retains rights to their “intellectual or
digital property.” DRM places limits or prohibitions on the customer’s ability to duplicate or re-distribute
the file, so as to prevent software piracy.
EFS
EFS is a transparent public key encryption technology that works in conjunction with NTFS permissions
to grant and deny users access to files and folders in Windows operating systems (2000 and above).
Entry control roster
An entry control roster, essentially, is a sign-in/sign-out list that employees and/or visitors must
complete before entering a facility, and also when leaving the facility. Such rosters document who is
entering and exiting a building, and lessens the likelihood of unauthorized persons entering a secure
facility.
EULA
EULA stands for end-user licensing agreement, which is a legal contract between a software developer
or vendor and the user of the software. It specifies in detail the rights and restrictions that apply to the
software. Copyrighted software products, like those from Microsoft, come with a EULA that details how
the software may be installed, used, or transferred to another computer. Open-source operating
systems and applications typically do not have a EULA, but may have an agreement the customer must
accept concerning product ownership, product development, and sharing the product with other people.
Hijacked email
Email systems are notorious for their lack of security. Such systems were never designed to enforce
user security, and typically there is no control over the kind of password that is used. So long as you
know the name of the email service provider, all you need to know is the individual’s email address.
Then, a hacker will use brute force attacks or simple guessing to determine the user’s password. There
is no limit to the number of times the hacker can guess in attempting to log in. Once the email password
is hacked, your email account is compromised.
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It is important to note that some of the most common email passwords are password, letmein,
abcd1234, and so forth. Unless the email provider enforces strong passwords, an account may be at
risk from day one.
If an email account is compromised, there are things you can do to resolve the problem.
1. Recognize the signs. Occasionally, a sender’s address (and other parts of the header) are altered to
hide the true source of an email. This is called "spoofing." You can see evidence of this spoofing, for
instance, when you receive a spam email that appears to come from your own address.
If your friends tell you they have received spam from your email address, it is safe to assume your
computer’s security has been compromised. You will want to proceed as if your computer has a virus or
other malicious software that places all the personal data at risk.
2. Notify friends. Use a different email address or another form of contact to warn friends and contacts
not to open anything from your compromised email address. Recommend that they use the most up-todate firewall and anti-virus protection available. Tell friends who have received spam from you to run a
scan using their anti-virus protection and to make sure all security patches are up to date.
3. Create a new email address. Make sure you use a strong password, combining numbers and letters,
for your new account. Also, to help ensure your future security, it is a smart idea to set up an additional
email account that you use solely for online purchases.
4. Maintain an inventory. Your email address is likely tied to many of your online activities. If your
account is compromised, you do not want the bad guys asking your bank to send a new user name and
password to that email account. Keep track of every activity tied to your email account, and if the
account is compromised, notify your bank, your credit card company and your other online accounts
that you have changed your email address.
5. Put online purchases on hold. You will want to make sure your computer is virus-free before you start
logging in credit card numbers for online purchases. Some malicious software enables criminals to
track every key stroke a computer makes.
6. Make sure your computer is clean. Run a strong anti-virus and anti-spyware program. Check to
make sure the firewall that came with your operating system is turned on. Make sure that you have
installed all the security patches for your operating system and antivirus/anti-malware applications.
7. Use your email user name wisely. Many people use the same user name as our email address on
these accounts. If your email is compromised, you will need to adjust those user names and vary the
names you use in the future.
Invalid certificates
When a user connects to certain websites, either for work purposes or to conduct e-commerce, the
website may install a certificate onto the computer that validates and verifies the authenticity of that
site. Without that certificate, the user cannot conduct business on the website. With that certificate, the
user can be somewhat assured that their interaction with the website is genuine and secure.
From time to time, a certificate issued by a legitimate website may expire. This is done to make sure
that anyone connecting to the site has a current, up-to-date certificate that complies to current security
criteria. Many times the certificates will be updated automatically when the user connects to the site.
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Sometimes the updated certificate will need to be downloaded from a secure “certificate store” and
installed manually. The Tools – Internet options dialog box in Internet Explorer will enable you to
manually install (or even remove) certificates used by browsers and various websites.
However, websites that harbor malicious software may attempt to install counterfeit or invalid
certificates. These bad certificates may cause your browser to redirect to other malicious websites, or
may cause your browser to malfunction. A good anti-malware application will be able to identify invalid
and/or malicious certificates and remove them safely.
Locking doors
Just what it sounds like, servers and important switching equipment should be in a secure room with a
locked door, to prevent tampering by unauthorized persons.
Man-in-the-middle attack
In cryptography and computer security, a man-in-the-middle attack (often abbreviated to MITM, MitM,
MIM or MiM attack or MITMA) is an attack where the attacker secretly relays and possibly alters the
communication between two parties who believe they are directly communicating with each other.
An example of man-in-the-middle attacks is active eavesdropping, in which the attacker makes
independent connections with the victims and relays messages between them to make them believe
they are talking directly to each other over a private connection, when in fact the entire conversation is
controlled by the attacker.
Non-compliant systems
If computer systems are not kept up-to-date with the latest security patches and operating systems
updates, a computer is considered to be “non-compliant”. Such systems constitute a threat to all other
computers and servers on a network, because they can become a gateway for malicious software to
affect the entire system.
Passwords
This is the most common process used to secure networked devices. This textbook has several
discussions on what constitutes an acceptable password for networked systems.
Patch Management
Patch management is an area of systems management that involves acquiring, testing, and installing
multiple patches (code changes) to an administered computer system. These patches can be applied to
an operating system, software applications, or antivirus/anti-malware applications. Patch management
ensures that all computers in an organization have been properly updated, so that security and proper
operation of all systems can be maintained.
Permission propagation
When you assign a permission to an object on a network (a file, folder, volume, printer), you can
choose whether the permission propagates down the object hierarchy. You set propagation for each
permission. Propagation is not universally applied. Permissions defined for a child object always
override the permissions that are propagated from parent objects. A “child object” necessarily has some
direct correlation to a “parent object”.
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For example, a “parent” trouble ticket issued in an IT service management program (like Remedy)
could spawn off several other “child” tickets, if a request has several distinct operations that need to be
completed. When all child tickets are resolved, the parent ticket would then be resolved as well.
Personal and enterprise licenses
Windows operating systems and software applications typically are sold to individual consumers. As
such, the customer is given a license to use that OS or application on only one computer. This is
considered a “personal license,” since it applies only to the person who purchased the product. Each
customer must “activate” the software by entering the 25-character code on the “Certificate of
Authenticity,” and then go online (or by phone) to validate the software as being authentic and uniquely
installed to only one computer. If the product has already been installed on another computer, the
software will not activate, and the application will not work properly.
When a business needs to purchase multiple copies of a Windows operating system or an office suite
application, Microsoft can sell the organization an “enterprise license” of that product. Enterpriselicensed products have a COA code like personally-licensed products, but they do not have to be
activated online or by phone. A pre-determined number of permitted licenses is included in the cost of
the product. Enterprise-licensed products are installed from DVDs like other products, but Microsoft
expects the businesses to exert control of how the installation media is distributed and used, in order to
prevent software piracy.
Phishing and spear-phishing
Phishing is the attempt to acquire sensitive information such as usernames, passwords, and credit card
details (and sometimes, indirectly, money), often for malicious reasons, by masquerading as a
trustworthy entity in an electronic communication.
Spear phishing is an email that appears to be from an individual or business that you know. But it isn't.
It's from the same criminal hackers who want your credit card and bank account numbers, passwords,
and the financial information on your PC. Attackers using spear phishing techniques may gather
personal information about their target to increase their probability of success. This technique is, by far,
the most successful on the Internet today, accounting for over 90 percent of attacks.
PII and BII
PII stands for personally-identifiable information, and BII stands for business identifiable information.
Both are considered to confidential forms of information, which should be protected from unauthorized
disclosure to the general public. Government agencies and many private businesses that deal with
consumers handle PII and BII data. Unauthorized disclosure of such information would constitute a
violation of the law, and both criminal and/or civil penalties could result for failure to handle this data in
a responsible manner.
Port disabling
TCP/IP, the protocol that allows computers to communicate on a network or over the Internet, uses
ports, which are addresses dedicated for specific kinds of data transfers. For example, hypertext
transfer protocol (HTTP) requests use TCP port 80, and secure HTTP (HTTPS) requests use TCP port
443. There are many ports available for use in TCP/IP, and any unused ports should be disabled, either
at a router on within the security settings on a PC. If a TCP port is disabled, no data can be transferred
over the network or Internet via that port.
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Networking routers also use ports when connecting to devices like computers and printers. Any unused
ports (plugs where a network cable can attach) should be disabled, to ensure that rogue users cannot
gain unauthorized access to the network or Internet. Routers typically have built-in software that allows
administrators to enable or disable ports on the device.
Principle of least privilege
The principle of least privilege (POLP) is the practice of limiting access to the minimal level that will
allow normal functioning. Applied to employees, the principle of least privilege translates to giving
people the lowest level of user rights that they can have and still do their jobs.
Network administrators must carefully analyze the needs of specific kinds of employees in their
organization, and ensure that any user’s rights are appropriate for their working roles, without giving
them too many or too few rights to networked resources.
Privacy filters and monitor shields
A privacy filter or monitor shield is a piece of polarized plastic or glass that is placed over a monitor. It allows
the user to see what is on the screen when looking directly at it, but prevents screen viewing from other
angles, especially by others standing nearby. This keeps people from “shoulder surfing”, where people
look over your shoulder searching for information they are not privy to viewing.
Rooting a phone
Rooting a phone (or tablet) means giving yourself root permissions on your device. It is similar to
running a program as an administrator in Windows, or running a command with sudo in Linux. With a
rooted phone, you can run apps that require access to certain system settings, as well as flash custom
ROMs to your phone, which add all sorts of extra features.
However, rooting a phone or tablet will void any warranty. You also must be very careful when
attempting to root the device; any mistakes could leave you with a non-functional device, from which
there may be no way to recover.
SecurID keyfobs and RSA tokens
These devices generate “random” numbers every 60-seconds, and these numbers are used in
conjunction with a user’s password to log into a secured system or network.
Security badges and RFID badges
Badges validate that the person possessing the badge has authorization to enter a secured area.
Certain badges have a smart chip or an RFID chip within them; when inserted into a card reader or in
close proximity to an RFID scanner, the person is permitted to log into a secured system or network.
Securing documents/ shredding
Anytime information of a confidential or proprietary nature is printed, those documents should be stored
in a secure area that will prevent unauthorized disclosure. When these documents are retired from use,
they should be shredded, burned, or destroyed in some fashion to preserve confidentiality.
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Shoulder surfing
Shoulder surfing is where people look over your shoulder at your monitor, searching for information
they are not privy to viewing. A privacy shield over your monitor will help to prevent that from
happening.
Spoofing
A spoofing attack is a situation in which one person or program successfully masquerades as another
by falsifying data, thereby gaining an illegitimate advantage.
SSO
Short for single sign-on, it is a process where once a customer successfully authenticates to a network,
all other networked resources that need authentication protection use the same credentials as were
used for the initial login. This simplifies access to multiple secure systems within an organization.
S/MIME
S/MIME (Secure/Multipurpose Internet Mail Extensions) is a standard for public key encryption and
signing of MIME data.
Tailgating
Tailgating is the process where an unauthorized person follows someone into a secure area that does
have authorization to enter that area.
Violations of security best practices
Security best practices are rules designed to provide the optimal level of protection for computers and
network systems. These rules have been developed and tested by organizations that use IT equipment,
and the rules are promoted and encouraged industry-wide. If a company does not adopt the use of best
practices, they increase the likelihood that a security breach or malware attack could impact individual
computers or the entire enterprise.
Zero-day attack and zero-day vulnerability
A zero day vulnerability refers to a hole in software that is unknown to the vendor. This security hole is
then exploited by hackers before the vendor becomes aware and hurries to fix it. This exploit is called a
zero day attack.
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Chapter 14. Local Area and Dial-Up Networking
This chapter covers a great deal of information on the topic of networking. In this chapter we will start by
discussing some very basic concepts about networking, and gradually build the foundation for
understanding more complex aspects of this subject. Both practical and theoretical aspects of networking
will covered in this chapter.
Local Area Networking
A network is a means whereby intelligent end-user PCs can share common resources, such as:
o A file server:
a dedicated computer with large hard disks that all network users
share; your application software and data will likely reside on this
file server, not on your PC's hard disk.
o A print server:
a computer dedicated to buffering print jobs sent by network users
to centralized or shared printers.
o A communications server:
a computer dedicated to allowing outside users access to the
network.
o An e-mail server:
A computer dedicated to providing e-mail (electronic mail) to users
of the network.
In a network, the end-user PCs are intelligent; that is, the terminals have a CPU in them that allows them,
NOT a centralized CPU, to do the computing work. This is called distributed processing. You have the
ability to log into the network (or work in standalone mode) and store your data either on a networked
drive OR on a local hard disk or flash drive, and your application software can be loaded from either a
local disk, or from the file server. The file server typically does NOT process the data; your local PC does.
In centralized processing, the terminals are not intelligent (they have NO CPU within them), and a
centralized CPU is shared by all users. You store your data in a centralized data storage facility, and run
your programs from the centralized CPU, sharing CPU time with all other users. You generally cannot
save your data to a local disk drive. When the centralized CPU goes down, so does everything.
Local area networks are exactly that: local. They are distributed over a small area, and allow a number of
users to share common resources. Generally, a LAN is limited to 255 users per LAN.
LANs can connect with other LANs to form a Wide Area Network (WAN), or can connect to mainframe on
minicomputers through devices like routers or bridges. This is how people can communicate from one
network in Washington to users on another network somewhere else, like in Seattle. Such a connection
could be made through leased phone lines, dedicated transmission lines, or by satellite.
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What exactly is a server?
A file server:
A file server is a dedicated, high-performance PC that has the following kinds of devices in it:
o
o
o
o
A large amount of Random Access Memory (RAM), usually 32 gigabytes or above;
Large hard drives (also called volumes), usually well above 1 terabyte (TB), with fast access times
(usually 10 ms or less) that are highly reliable and can take the stress of multiple users accessing
the drives for long periods of time;
One or more network cards, usually running at 1gigabit per second (1Gbps); and
The Windows Server operating system or a Linux operating system loaded onto it, so that multiple
users will have access to the drives on the file server.
The file server has one function in life: giving you access to files and information stored in it's hard disks,
and other available online resources.
A print server:
A print server is higher-end dedicated PC that has the following kinds of devices in it:
o
o
o
o
An average amount of Random Access Memory (RAM), usually 4 – 8 gigabytes;
Typical hard drives (usually above 500 GB) with average access times (usually 12 ms or less) that
are reliable enough to take the stress of multiple users accessing the drives for long periods of
time;
A decent network card, usually running at 1Gbps; and
The print spooler portion of a network operating system loaded onto it, so that multiple users will
be able to send print jobs to the server. The shared printer usually will be attached to the print
server, but this is not necessarily always the case.
The print server has one function in life: giving you the ability to share a network printer with multiple
users on the network system.
A communications server:
A communications server is a specialized type of PC that has the ability to allow outside users to connect
to the network from remote locations. This allows remote users the same kinds of network capabilities as
those connected to the network in-house.
Older communications servers that enabled telephone dial-up access to a network were called
chatterboxes. Each device within the communications server contains a self-contained PC on a card,
with a modem of some type built into the card. Chatterboxes were somewhat expensive, but they gave
remote users a great deal of flexibility to process data in the field.
With the advent of broadband Internet access, communications servers generally provide Virtual Private
Networking (VPN) access to internal network resources in a secured fashion. These servers enable
companies to offer options like telework to their employees, and allow individuals to access internal
system data while on business travel.
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An e-mail server:
An e-mail server is like the file server mentioned above, and it runs a server-based host electronic mail
package running upon it (like Microsoft Exchange or Lotus Notes). E-mail allows you to send
messages and files from one network user to another.
The mail server needs to have large hard drives to accommodate all of the messages being sent to and
from users within the network. Periodically the list of mail messages may need to be purged, to eliminate
old messages that should have been deleted from the system long ago. One would do this in order to free
up disk space on the mail server for new messages. Email applications like Microsoft Exchange and
Lotus Notes give administrators and users the option to delete and archive mail messages automatically
when a message gets to a certain age.
Major types of network topologies
Ethernet bus
An Ethernet Bus network is like a "highway for data." Data is passed in a "party-line" fashion; each PC
waits for quiet on the line, then transmits the message down the line to the next station. Each PC or
workstation on the bus checks to see if a message is traveling along the bus before sending their
messages. All messages pass through all workstations on their way to their destination.
When using coaxial cables, a terminator (or terminating resistor) is placed at both ends of the cable so
that the devices on the network can determine the end of the signal run. Twisted-pair (10BaseT) or
ethernet cables typically are used in modern Ethernet bus networks. A broken coaxial cable or
un-terminated coaxial cable run, however, can crash the entire network.
StarLAN (including ARCNet) [obsolete]
A StarLAN (or ARCNet) network sends messages from the file server to an intelligent hub, which routes
the network message to the proper PC or workstation. StarLAN networks pass tokens which are
specifically for one and only one PC on the network. The failure of one PC or cable line from hub to PC
will not cause a system-wide network failure, as with an Ethernet bus network. Twisted-pair (10BaseT) or
coaxial ethernet cables are generally used with such a network. This system passes data much like the
phone company routes telephone calls, through the use of the hubs as switching devices. StarLAN and
ARCNet networks are obsolete, and have been for some time.
Token Ring
Token ring networks also send messages in the form of tokens from one PC/workstation to another, in an
"assembly-line" fashion. If there is a break in the cable scheme, the token is then passed in the opposite
direction towards the receiving PC. The ring topology allows verification that a message has been
received by the proper PC. Extensive monitoring of the network is possible in a ring topology. Failure of a
single workstation or a break in the network line will not cause a system-wide network failure. Additional
rings can be accessed through bridges, which control the flow of information between the ring networks.
There are three things that can cause a networked PC to fail to connect in any of these types of
topologies (excluding a server failure):
●
●
●
Bad network cable; this is responsible for at least 50 percent of networking failures;
Bad (defective) Network Interface Card (NIC); and
Networking software is not configured correctly for that PC
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How do networks pass data from one place to another?
Ethernet networks
Ethernet networks pass data in a "party-line" fashion. That means the network waits for quiet on the
communications line, and then it "shouts as loud as it can, hoping to be heard". The more users there are
on the network, the more crowded and confused the communications line becomes, and the less efficient
the network becomes as well. Data is passed from one PC to another, with the NIC in each PC
re-broadcasting the signal as it goes along the line. Network switches improve the performance of
Ethernet network by transmitting data directly to PCs, because the switch can identify the Media Access
Control (MAC) address of all network cards in the system.
Token-ring and ARCNet/StarLAN networks
Token-ring networks (and obsolete ARCNet/StarLAN networks) pass data in an "assembly-line" fashion.
That means that the network passes data in the form of tokens at a consistent, regular rate of speed. The
same number of tokens are passed at the same speed whether there are 5 nodes or 150 nodes on the
network. Tokens are "marked" as to who is the intended recipient of the token. Token-passing is
bi-directional; if the recipient can't receive the token via one route of cable, the network will send the token
in the opposite direction of the cable in an attempt to find the recipient.
Media Access Control (MAC) address numbers
All data transmitted on networks are coded with a 16-digit media access control (MAC) address that
indicates the intended recipient of the information. This MAC address is unique to each network interface
card (NIC); no two NICs anywhere have the same MAC address. The network software uses this MAC
address in its work to transmit data from one place to another.
How will my computer operate if it is connected to a LAN?
For the most part, your computer will operate on a LAN just at as it would without a LAN. You will log onto
a disk drive (that is actually a network drive), change directories to the place where your application
software is located, and execute your program just as you would if the software were on your hard drive
inside your PC.
Several things will have to happen, though, in order for you to gain access to your network drive(s):
1)
You will have to load and run some kind of driver software that makes your PC able to use the
network card plugged into the bus connection inside your PC. Drivers will need to be loaded in
Windows to enable the network card.
2)
You will need to run the network operating system client programs and protocols needed to
initialize your network card for use by the operating system, identify your PC as a legitimate node
on the network, and allow an identified user to log into the network. In a Windows environment,
the Microsoft networking client is installed by default with the rest of the operating system. Also
loaded are the protocols (language equivalents for networks) needed so that data can be
exchanged from one place to another. These protocols include TCP/IP, or older (obsolete)
networking protocols such as NetBEUI and Novell IPX/SPX.
3)
Your network administrator will have to map specific drive designations to you, grant you rights
to access files in the drive and directory, and use specific commands to route your print requests
to a networked printer.
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4)
You will most likely access most of your application software on the network drives available to
you after you have logged into the network..
For the most part, everything is the same on a network drive as it is on a local hard drive. You can obtain
a directory of files on your network drive and subdirectory; you can copy files from one place to another;
deleting and renaming files works in the same way. The idea of a network drive is to give you as identical
an environment on a network drive as you do on a local hard drive.
What happens when the server breaks down?
EVERYTHING STOPS!
More specifically, when the file server breaks down, no one is able to access their programs or data.
Further, you may not be able to save your work out to the file server, or even to your local hard disk as a
last resort. The scenario is much like when the lights all go out in a dark theater: no one knows where to
go, and everyone steps on each other trying to get out. The file server is the most important link in data
access, retrieval and storage. If it goes down, all of these processes stop as well. It's just like when your
hard disk quits in the middle of a computing session; when it fails, great is the fall thereof.
When the print server breaks down, all of the print jobs in the print queue will be lost. Once the print
server is re-booted, you then may re-send your print job back to the server, where it will process the job
for you.
When the communications server breaks down, your outside connection to the internal network is lost.
You will not be able to re-establish your outside link into the network until the communications server is
brought back on-line.
When the e-mail server breaks down, you will be unable to access the e-mail service on the LAN.
Depending on the severity of the problem, you may lose some or all of your mail messages, especially
those that were sent just before the crash. If the hard disk on the mail server is severely damaged, you
will very likely lose some or all of your e-mail messages. If it's just a problem with a locked-up mail server
or a temporary communications problem, you will likely be back in business in short order, with little or no
loss of mail.
Data backups with mirroring, duplexing and striping
Most servers have some means of backing up their hard disks, which are also called volumes. Most file
servers duplex their disks; this is where 2 hard disks (each with a separate disk controller) make mirror
image copies for all data transactions going onto the server. Some servers use mirroring; this is where 1
disk controller creates two mirror image copies of each file on 2 separate hard disks. The problem with
mirroring comes when the 1 disk controller crashes, and both drives go off-line. Duplexing allows the
backup disk drive to continue working while the primary controller or hard disk is off-line or being repaired.
Striping is a technique for spreading data over multiple disk drives. Disk striping can speed up
operations that retrieve data from disk storage. The computer system breaks a body of data into units and
spreads these units across the available disks. Systems that implement disk striping generally allow the
user to select the data unit size or stripe width.
These types of data storing methods involve the use of RAID (Redundant Array of Independent Drives)
drive arrays. RAID drives can be installed within a file server, or separately in network-attached storage
(NAS) device or a Storage Area Network (SAN).
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Disk striping is available in two types. Single user striping uses relatively large data units, and improves
performance on a single-user workstation by allowing parallel transfers from different disks. Multi-user
striping uses smaller data units and improves performance in a multi-user environment by allowing
simultaneous (or overlapping) read operations on multiple disk drives.
Disk striping stores each data unit in only one place and does not offer protection from disk failure.
IF I unplug or disconnect my network cable, what happens to the LAN?
Generally, very bad things happen when you make a break in the network cable.
If you have an Ethernet bus network:
Breaking the cable line has disastrous effects on the network. In an coaxial Ethernet bus network, a cable
break can cause a system-wide crash that affects EVERYONE on the network. A coaxial bus cable line
has a terminator at the end of the line, which reflects signals back to the server(s). If the server cannot
locate the end of the cable line or receive back the reflected signal, the server becomes unable to
communicate with any device located on the network. Signals from PCs attempting to communicate with
the server either get lost down the broken cable line, or collide with the signals from other PCs attempting
to communicate on the LAN.
Even a momentary break in connection can crash a group or an entire network of PCs. Therefore, DO
NOT DO IT! If you are simply disconnecting your PC from the LAN, and you are NOT creating a break in
the line, that is acceptable. Just unplugging your PC from the LAN will not crash the system; creating a
break in a coaxial cable line WILL crash the network.
Most Ethernet bus networks now use CAT-5-style hubs or routers (that use twisted-pair cables) to create
direct connections between these devices and individual PCs. This creates a situation where Ethernet
bus networks are more stable and less prone to serious failures if a disconnection takes place. If there is
a break in a network cable between the hub/router and a PC, only one PC is affected. However, creating
a cable break to a hub or router will cause a number of users on a network to suffer disconnection. Care
must be exercised whenever performing cable maintenance, to reduce or eliminate the potential for
customers being disconnected from critical resources.
If you have a Token Ring network:
Breaking the line in one of these types of LANs will generally not have the same kind of disastrous effects
as with an Ethernet LAN. Since these LANs communicate through the passing of tokens from PC to PC
through the use of a networking hub, having a cable break becomes less of an issue. If a PC drops out of
the loop, the LAN bypasses that PC and passes the token to the next available PC. If you are the PC for
which the token is designated, and your PC is the one that goes off-line, the token is returned to the
server as undeliverable. In an ARCNet or StarLAN setting, if you break the cable between the server and
the hub, you may cause serious problems for the rest of the network, and could potentially crash the
network.
In any setting, if you break the line from the file server to the rest of the network, you create a major
system failure.
As a general rule, never disconnect or create a break in any network cable line during prime use hours,
always inform all users before making a break in the line, and attempt to isolate the cable run from the
rest of the LAN before making breaks or repairs to the line.
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Can computer viruses be spread through a LAN, and can my computer become infected?
Absolutely.
Viruses are passed from disk to disk. Your network disk drive is no different than a USB flash drive or
hard drive in your PC, with respect to passing viruses. If you copy an infected file from your hard disk to a
network disk, the network drive will be infected AND anyone copying that file from the server to their hard
disk or other disk drives will become infected as well.
Therefore, it is vital that you or your network administrator include in your SYSTEM LOGIN SCRIPT or in
a GROUP POLICY OBJECT some type of virus protection program that will scan your hard disk for
viruses, and remain memory-resident during your computing session to alert you to any virus threats to
your computer during your session.
There are many good virus protection programs available on the market today, such as the free AVG
Antivirus program. Other pay-for-protection programs, such as Trend Micro or Symantec Internet
Security, also are available. Carefully evaluate the claims and performance of any antivirus solution
before installing it on end-user computers or networked servers.
It is also important for you to emphasize to your users to be aware of computer viruses, and instruct them
NOT to load anything from a disk up to a server or local hard disk until the disk has been scanned by a
virus protection program. Also, users should routinely scan the files on their network drives for viruses,
just as a precaution.
How do I install a Network Interface Card (NIC)?
There are several steps involved in installing a network interface card (or NIC) into a PC:
1)
2)
3)
4)
5)
6)
7)
Open the computer case;
If the NIC is Plug-and-Play compliant, there will be no jumpers or switches to set; the installation
script that runs with the "Add New Hardware Wizard" will install the modem to the correct
parameters for you;
Install the new NIC in any free white PCI bus connection;
Attach the network cable to the RJ-45 jack on the NIC, and make sure the other end is attached to
the network wall jack;
Power up the PC; if you are Windows 2000 or above, the operating system should detect a new
NIC; insert the driver installation disk into the CD/DVD-ROM drive, and make sure the operating
system locates the correct driver for the NIC;
Install any network client software you desire, such as the Microsoft Networking client (which is
installed by default when installing the operating system); then, make sure that you configure the
TCP/IP networking protocol for the type of client you will be using; then, test the NIC by attempting
to log onto the network;
Replace the computer case - do NOT install the cover until you know the card is working properly.
Refer to the Network Interface Card Installation checksheet in Chapter 5 of this book for further details on
this topic.
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The networking “laundry list”
The following things will ALL have to be installed, setup and work properly for your network connection to
function as it should:
o
o
o
o
o
o
o
o
o
o
o
o
o
The PC (or laptop) has a network interface card (NIC) that is in good working order (wired or
wireless)
The NIC has the proper drivers loaded, and the device appears as working in the Windows Device
Manager
You have a network cable (typically CAT-5, CAT-5e or CAT-6) that is in good working order
You have a working router, switch or hub to allow you to connect to the rest of the network
For a wireless network, you have the proper WEP key or WPA pass-phrase (password) to access
the router
When the network cable is attached to the PC AND to the router/switch/hub, you will see an
illuminated link light on both the NIC and the router/switch/hub
You have the proper networking client installed in the operating system (typically Microsoft or
Novell)
You have your networking protocol (TCP/IP primarily) installed and configured properly
You have a valid account on the network (for account-based or domain-based networks)
You know how to log into the network (from the login prompt or login screen)
You know that the account is not locked out or expired
You use the correct username and password combination
You have the rights to see or modify the desired files and folders on the network file server(s), or
networked printers, or other kinds of network-attached devices
If ALL of these things are setup correctly, your connection to the network will operate as expected.
If ANY of these things is NOT setup properly, you will have a “not-work” … because the network will not
work for you.
This list is the foundation to understanding all of the separate parts of what makes up a network. We will
discuss these issues in detail in the lecture portion of the class, and you will use this list in the lab
sessions to ensure that your connection to a local area network operates as expected.
Later in this chapter we will discuss the OSI (Open Systems Interconnection) model, which defines in a
theoretical way a networking framework for implementing networks and their protocols in seven layers.
This laundry list will help you in the most practical ways to understand the functional workings of a
network, and how everything connects and communicates.
You can use this checksheet to help in setting up or troubleshooting a local area network.
NOTES
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Basics of configuring IP addressing and TCP/IP properties (DHCP, DNS)
Dynamic Host Configuration Protocol (DHCP) is a protocol for assigning dynamic IP addresses to
devices on a network. With dynamic addressing, a device can have a different IP address every time it
connects to the network. In some systems, the device's IP address can even change while it is still
connected. DHCP also supports a mix of static and dynamic IP addresses. Static (unchanging) IP
addresses are used primarily for network servers, web servers and printers that require the use of the
same address on a continuing basis.
Dynamic addressing simplifies network administration because the software keeps track of IP addresses
rather than requiring an administrator to manage the task. This means that a new computer can be added
to a network without the hassle of manually assigning it a unique IP address. Many ISPs use dynamic IP
addressing for dial-up users.
Windows-based PCs and Macs running the Mac operating system have DHCP enabled by default. The
DHCP client software on the PC interacts with a DHCP server (or service) to obtain an IP address for that
computer. Most commercial routers assign DHCP addresses to the PCs connected to them; this is
especially true for home or small-office routers that assign private IP addresses in the 192.168 range to
all computers in the home or business. DHCP can be enabled or disabled for the PC by opening the
TCP/IP Properties tab in the Network connection Control Panel applet. When DHCP is disabled, the user
must input a static (unchanging) IP address in the TCP/IP Properties tab.
Domain Name System (or Service or Server) is an Internet service that translates domain names into IP
addresses. Because domain names are alphabetic, they're easier to remember. The Internet however, is
really based on IP addresses. Every time you use a domain name, therefore, a DNS service must
translate the name into the corresponding IP address. For example, the domain name
www.mydomain.com might translate to 147.105.232.4.
The DNS system is, in fact, its own network. If one DNS server doesn't know how to translate a particular
domain name, it asks another one, and so on, until the correct IP address is returned.
Bandwidth and latency
Bandwidth can be defined as a range within a band of available transmission frequencies or wavelengths.
It also can be defined as the amount of data that can be transmitted in a fixed amount of time. For digital
devices, the bandwidth is usually expressed in bits per second(bps) or bytes per second. For analog
devices, the bandwidth is expressed in cycles per second, or Hertz (Hz).
The bandwidth is particularly important for I/O devices. For example, a fast disk drive can be hampered
by a bus with a low bandwidth. This is the main reason that new buses, such as AGP, have been
developed for the PC.
For networks, bandwidth is the amount of data that can be transmitted on a given type of cable or other
transmission method (like wireless). For example, fiber optic cable has mode bandwidth capability than
does coaxial cable or CAT-5, CAT-5e, CAT6 or 6e, or CAT-7 twisted-pair network cable. Knowing the
bandwidth capability of a cable or wireless technology helps you to determine if there is (or is not) enough
capacity to support the number of users on a given network system.
In networking, latency refers to the amount of time it takes a packet to travel from source to destination.
Together, latency and bandwidth define the speed and capacity of a network.
In VoIP terminology, latency refers to a delay in packet delivery. VoIP latency is a service issue that is
usually based on physical distance, hops, or voice to data conversion.
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Full-duplex and half-duplex transmission
Full-duplex refers to the transmission of data in two directions simultaneously. For example, a telephone
is a full-duplex device because both parties can talk at once. In contrast, a walkie-talkie is a half-duplex
device because only one party can transmit at a time.
Most NICs (and even older dial-up modems) have a “software switch” that lets you choose between
full-duplex and half-duplex modes. The typical NIC can automatically switch between these two modes,
depending upon how the data is being transmitted by the switch or router to the PC.
In full-duplex mode on a chat or telnet program, data you transmit does not appear on your screen until it
has been received and sent back by the other party. This enables you to validate that the data has been
accurately transmitted. If your display screen shows two of each character, it probably means that your
modem is set to half-duplex mode when it should be in full-duplex mode.
Status indicators
On the back of a typical network interface card (NIC), router, switch or a hub, there are several LED lights
called status indicators that will tell you the following:
Link indicator: the light illuminates when a good cable connection is made from the NIC to the hub, switch
or router; the light does not illuminate if the cable connection is broken, or if the NIC is not functioning
(usually because the driver is not loaded, or the power to the system is off).
Speed indicator: the LED(s) will indicate whether the NIC is transmitting data at 10Mbps, 100Mbps, or
1000Mbps; Some NICs use only one LED speed indicator, while others have a separate LED for each
speed level.
Basics of workgroups and domains
A workgroup is a collection of individuals working together on a task. Workgroup computing occurs when
all the individuals have computers connected to a network that allows them to send e-mail to one another,
share data files, and schedule meetings.
A workgroup has a name (such as MSHOME or WORKGROUP), and each computer can “join” the group
by changing their network settings in the “Computer name” tab in the System Properties Control Panel
applet.
Workgroups are by their design a “peer-to-peer” networking environment; a centralized server is not
necessary, and people can share files, disk and printing resources within the group without having to log
into a server.
A domain is a group of computers and devices on a network that are administered as a unit with common
rules and procedures. Within the Internet, domains are defined by the IP address. All devices sharing a
common part of the IP address are said to be in the same domain.
In Windows networking, domain-based networks have a centralized server referred to as the domain
controller. A user must specify the domain in the “Computer name” tab in the System Properties Control
Panel applet, and must log into the domain controller in order to use any of the resources within the
network. Further, the user must have a username and password combination setup beforehand by the
system administrator in order to log into the domain-based network.
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Common ports used in TCP/IP for AFP, HTTP, FTP, POP, SMB, SMTP, TELNET, HTTPS
In TCP/IP and UDP networks, a port is an endpoint to a logical connection and the way a client program
specifies a specific server program on a computer in a network. Some ports have numbers that are
preassigned to them. Port numbers range from 0 to 65536, but only ports numbers 0 to 1024 are reserved
for privileged services and designated as well-known ports.
Knowing the correct port numbers will enable you to trouble-shoot connection problems or failures,
especially if a TCP/IP port has been closed or disabled by a router.
Here are some of the commonly-used TCP/IP sub-protocols, and the port assignments they use:
Sub-Protocol
Port Number
AFP:
FTP:
HTTP:
HTTPS:
IMAP:
POP3:
SMTP:
SMB:
TELNET:
548 or 427
20, 21
80
443
143
110
25
137-139, 445
23
You will need to know these port assignments listed above for the A+ examination.
Differences between a hub, switch and router
A hub is a common connection point for devices in a network. Hubs are commonly used to connect
segments of a LAN. A hub contains multiple ports. When a packet arrives at one port, it is copied to the
other ports so that all segments of the LAN can see all packets.
A passive hub serves simply as a conduit for the data, enabling it to go from one device (or segment) to
another. So-called intelligent hubs include additional features that enables an administrator to monitor the
traffic passing through the hub and to configure each port in the hub. Intelligent hubs are also called
manageable hubs.
A third type of hub, called a switching hub, actually reads the destination address of each packet and then
forwards the packet to the correct port.
A switch is a device that filters and forwards packets between LAN segments. Switches operate at the
data link layer (layer 2) and sometimes the network layer (layer 3) of the OSI Reference Model and
therefore support any packet protocol. LANs that use switches to join segments are called switched LANs
or, in the case of Ethernet networks, switched Ethernet LANs.
A router is a device that forwards data packets along networks. A router is connected to at least two
networks, commonly two LANs or WANs or a LAN and its ISP’s network. Routers are located at
gateways, the places where two or more networks connect.
Routers use headers and forwarding tables to determine the best path for forwarding the packets, and
they use protocols such as the Internet Control Message Protocol (ICMP) to communicate with each
other and configure the best route between any two hosts. Very little filtering of data is done through
routers.
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IP Security (IPSec)
A set of protocols developed by the Internet Engineering Task Force (IETF) to support secure exchange of
packets at the IP layer. IPSec has been deployed widely to implement VPNs. IPSec supports two encryption
modes: Transport and Tunnel. Transport mode encrypts only the data portion (payload) of each packet, but
leaves the header untouched. The more secure Tunnel mode encrypts both the header and the payload.
On the receiving side, an IPSec-compliant device decrypts each packet. For IPSec to work, the sending and
receiving devices must share a public key. This is accomplished through a protocol known as Internet Security
Association and Key Management Protocol/Oakley (ISAKMP/Oakley), which allows the receiver to obtain a
public key and authenticate the sender using digital certificates.
L2TP
Short for Layer Two (2) Tunneling Protocol, an extension to the PPP protocol that enables ISPs to operate Virtual
Private Networks (VPNs). L2TP merges the best features of two other tunneling protocols: PPTP from Microsoft
and L2F from Cisco Systems. Like PPTP, L2TP requires that the ISP's routers support the protocol.
PPTP
Short for Point-to-Point Tunneling Protocol, a technology for creating VPNs, developed jointly by Microsoft,
U.S. Robotics and several remote access vendor companies, known collectively as the PPTP Forum. A VPN is a
private network of computers that uses the public Internet to connect some nodes. Because the Internet is
essentially an open network, PPTP is used to ensure that messages transmitted from one VPN node to another
are secure. With PPTP, users can dial in to their corporate network via the Internet.
Virtual Private Networks (VPN)
Short for virtual private network, a VPN is a network that is constructed by using public wires to connect nodes.
For example, there are a number of systems that enable you to create networks using the Internet as the medium
for transporting data. These systems use encryption and other security mechanisms to ensure that only
authorized users can access the network and that the data cannot be intercepted.
Companies and organizations will use a VPN to communicate confidentially over a public network and to send
voice, video or data. It is also an excellent option for remote workers and organizations with global offices and
partners to share data in a private manner.
A VPN is designed to provide a secure, encrypted tunnel in which to transmit the data between the remote user
and the company network. The information transmitted between the two locations via the encrypted tunnel
cannot be read by anyone else.
VPN security contains several elements to secure both the company's private network and the outside network,
usually the Internet, through which the remote user connects through. The first step to security is usually a
firewall. You will have a firewall site between the client (which is the remote users workstation) and the host
server, which is the connection point to the private network. The remote user will establish an authenticated
connection with the firewall.
Encryption is also an important component of a secure VPN. Encryption works by having all data sent from one
computer encrypted in such a way that only the computer it is sending to can decrypt the data. Types of
encryption commonly used include public-key encryption which is a system that uses two keys: a public key
known to everyone and a private or secret key known only to the recipient of the message.
The other commonly used encryption system is a Symmetric-key encryption system in which the sender and
receiver of a message share a single, common key that is used to encrypt and decrypt the message.
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With a VPN you'll need to establish a network connection that is based on the idea of tunneling. There are two
main types of tunneling used in virtual private networks. Voluntary tunneling is where the client makes a
connection to the service provider then the VPN client creates the tunnel to the VPN server once the connection
has been made. In compulsory tunneling the service provider manages the VPN connection and brokers the
connection between that client and a VPN server.
There are three main network protocols for use with VPN tunnels, all of which are generally incompatible with
each other. They include the following:
Basics of IP address class identification
Since it is necessary for all IP addresses on the Internet to be unique, a system was created for dividing up the
available addresses and share them amongst those organizations. A central authority was established for this
purpose, and a scheme developed for it to effectively allocate addresses.
The developers of IP recognized that organizations come in different sizes and would therefore need varying
numbers of IP addresses on the Internet. They devised a system whereby the IP address space would be divided
into classes, each of which contained a portion of the total addresses and were dedicated to specific uses. Some
would be devoted to large networks on the Internet, while others would be for smaller organizations, and still
others reserved for special purposes.
There are 5 classes of IP addresses: Class A, B, C, D and E. Class E addresses are reserved for experimental
uses, and Class D addresses are used for IP multicasting.
For large amounts of data, IP multicasting is more efficient than normal Internet transmissions because the
server can broadcast a message to many recipients simultaneously.
Unlike traditional Internet traffic that requires separate connections for each source-destination pair, IP
multicasting allows many recipients to share the same source. This means that just one set of packets is
transmitted for all the destinations.
Class A addresses are used for unicast addressing for very large organizations with hundreds of thousands or
millions of hosts to connect to the Internet. Class A addresses comprise about 50 percent of the total number of
IP addresses. The IP address itself has 8 data bits in the network ID, and 24 data bits in the host portion of the ID.
Class B addresses are used for unicast addressing for medium-to-large organizations with many hundreds to
thousands of hosts to connect to the Internet. Class B addresses comprise about 25 percent of the total number
of IP addresses. The IP address itself has 16 data bits in the network ID, and 16 data bits in the host portion of the
ID.
Class C addresses are used for unicast addressing for smaller organizations with no more than about 250 hosts
to connect to the Internet. Class C addresses comprise about 12.5 percent of the total number of IP addresses.
The IP address itself has 24 data bits in the network ID, and 8 data bits in the host portion of the ID.
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All public IP addresses are distributed through a centralized and administered source, to ensure that no address
conflicts occur on a national or global basis.
Here is a chart that shows the major IP address ranges:
What are the major networking protocols?
TCP/IP - the current standard networking protocol
TCP/IP stands for Transmission Control Protocol / Internet Protocol. Both the Microsoft and the Novell
networking clients can use TCP/IP. TCP/IP can be used for local area networks, wide area networks, virtual
private networks, and it is the protocol used on the Internet.
Within the TCP/IP protocol are a set of utilities that allow the user to do a variety of things over a network or the
Internet:
o
o
o
o
o
o
o
HTTP: this is an acronym for Hypertext Transfer Protocol. This protocol enables users to create text
documents with links that let the user go from one point on the Internet to another.
HTML: this is an acronym for Hypertext Markup Language. This type of text works together with the
Hypertext Transfer Protocol to allow users to click on links within a text document that will transfer you to
another text document on the Internet.
FTP: this is an acronym for File Transfer Protocol. FTP allows the user to log onto sites on the Internet
that have files available for download, and it also allows the user to place files onto such Internet sites.
PING: this utility lets you send a 32-byte packet to a remote site on the Internet, in order to test your PC's
ability to communicate over the Internet. The remote site, once it receives the packet, returns a 32-byte
packet to the computer which sent it.
IPCONFIG: this is a text-based utility run from the MS-DOS command prompt in Windows 2000 through
Windows 8; it provides the user with all of the relevant IP addressing information currently in place on
your PC.
TRACERT: this utility lets the user trace the route data takes from a remote host to your PC.
NSLOOKUP: this utility lets you perform a name search lookup for a specific Internet web site.
NetBIOS
Short for Network Basic Input Output System, NetBIOS is an application programming interface (API) that
augments the DOS BIOS by adding special functions for local-area networks. Almost all Windows-based LANs
for PCs are based on the NetBIOS. Some LAN manufacturers have even extended it, adding additional network
capabilities.
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Older, obsolete protocols
IPX/SPX [obsolete]
The Novell networking client uses the IPX/SPX protocol. IPX is a datagram protocol used for connectionless
communications. Higher level protocols such as SPX (and NCP) are used for additional error recovery services.
This protocol is routable, and is suitable for large networks. However, IPX/SPX cannot be used on the Internet.
Therefore, IPX/SPX has seen a decline in use in the past few years.
NetBEUI [obsolete]
NetBEUI stands for NetBIOS Enhanced User Interface. The Microsoft networking client can use the NetBEUI
protocol. This protocol is suitable for small networks of 2 to 20 users. However, this protocol is not routeable;
that is, it cannot pass through a router and connect to larger networks. NetBEUI also transmits a great deal of
data across the backbone, which slows the performance of the entire network. NetBEUI, therefore, is not widely
used within the networking community.
Universal Naming Convention (UNC) names
On many networks, rather than assigning a drive letter to a network volume (such as H:), network operating
systems (including Unix/Linux and Microsoft networking) allow the use of universal naming convention (UNC)
names for network volumes. A UNC name might look like the following:
\\server1\disk1\dirname1:
UNC names are used in a Windows environment, and also in a Unix/Linux environment. UNC names allows
Windows users to access data on disk volumes from various operating system platforms. For Windows-based
computers, the SAMBA application allows you to assign a drive-letter to a folder on a Unix/Linux-based server.
IP version 6 compared to IP version 4
Internet Protocol version 6 (IPv6) is the latest revision of the Internet Protocol (IP), the communications protocol
that provides an identification and location system for computers on networks and routes traffic across the
Internet. IPv6 was developed by the Internet Engineering Task Force (IETF) to deal with the long-anticipated
problem of IP version 4 (IPv4) address exhaustion.
IPv6 is intended to replace IPv4, which still carries the vast majority of Internet traffic as of 2013. As of late
November 2012, IPv6 traffic share was reported to be approaching 1%.
Every device on the Internet must be assigned an IP address in order to communicate with other devices. With
the ever-increasing number of new devices being connected to the Internet, the need arose for more addresses
than IPv4 is able to accommodate.
IPv6 uses a 128-bit address, allowing 2128, or approximately 3.4×1038 addresses, or more than 7.9×1028 times as
many as IPv4, which uses 32-bit addresses. IPv4 allows only approximately 4.3 billion addresses. The two
protocols are not designed to be interoperable, which complicates the transition to IPv6.
IPv6 addresses are represented as eight groups of four hexadecimal digits separated by colons; for example:
2001:0db8:85a3:0042:1000:8a2e:0370:7334
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IPv6 has additional features that IPv4 does not have; in particular:






More available IP addresses than in IPv4
Multicasting (the transmission of a packet to multiple destinations in a single send operation)
Stateless address auto-configuration (SLAAC), which allows IPv6 hosts can configure themselves
automatically when connected to an IPv6 network using the Neighbor Discovery Protocol via Internet
Control Message Protocol version 6 (ICMPv6) router discovery messages
Improved network-layer security, through the use of Internet Protocol Security (IPsec)
Simplified processing of network packets and packet forwarding by routers
Enhancements to network privacy
IPv6 implementation has been slow, mainly because older network routers will need to be upgraded, and IPv6
network capable devices have been slow to reach the market. Further, network administrators would need to
upgrade and change their client computers to implement IPv6, rather than stay with IPv4.
Major government agencies and large multi-national businesses are now moving to implement IPv6, which
should speed the adoption of this new standard.
NOTES
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OVERVIEW OF SMALL-OFFICE AND HOME-OFFICE (SOHO) NETWORKING SYSTEMS
Many families and small offices have more than one PCs. You should set up a small network to better utilize the
computing power and resources in PCs. Also, by setting up a network, you can share an internet connection. No
more fighting on who can surf the internet.
There are basically two type of networking: peer-to-peer networking and server-based networking.
Peer-to-peer networking
This type of network is easy to configure, inexpensive and ideal for home and small offices. In a peer-to-peer
network, each computer shares information stored on it with other computers or peers, on the network.
Peripheral devices such as printers and scanners can be shared as well. The disadvantage of peer-to-peer
networking is that it's relatively insecure. Everyone on the network can access the files you've designated to
share. However, there are measures you can implement to remedy this issue.
Server-based networking
Server-based networks are built around a centralized computer called a server. This type of networking is also
referred to as server-client network. The server holds all the network's shared information which the client
computers can access. The server-base network is popular with the business world because it's easier to
manage and offers a better security for the information stored on the server.
However, server-based networks are more expensive to set up and maintain. At least one dedicated computer is
needed to act as a server. A more expensive operating system specifically designed to run on a server computer
is also needed. In addition, a knowledgeable network administrator is needed to manage the server. As you can
see, server-based networking is not necessary for home use.
After you have decided which networking scheme meets your need, you then need to decide how you want to
physically connect the network. There are generally two choices you can pick: cabled networks and wireless
networks.
Cabled networks
Until recently, almost all networks are connected by network cables and network devices such as hubs and
switches. This type of connection is fast, reliable and relatively inexpensive. It's also more secure than wireless
network. However, there are drawbacks with network cable in SOHO setting.
You need to connect each computer with a network cable which is difficult to do, especially if you live in a
multi-story house and the computers are not close to each other. Fortunately, to avoid hole drilling and tangling
layout of network cables, wireless networking provides a more elegant solution.
Wireless networks
Wireless networks are getting more and more popular with the home networking market. This type of networking
offers much greater flexibility and freedom. Instead of connecting PCs using cables and switches, wireless
networking uses wireless access points, routers and wireless NIC cards.
However, there are drawbacks with wireless networking as well. Wireless networks can be up to ten times slower
than cabled networks. Wireless networks can be less secure than wired networks, due to the fact that signals are
broadcast in the air for up to 800 feet. Fortunately, there are security measures you can implement to minimize
the risk.
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Setting up a Small Office / Home Office (SOHO) network
Many people are unaware of how easy and inexpensive it is to interconnect existing computers to form a small
Local Area Network (LAN). If you are using Windows, no additional software is required to enjoy basic network
functions such as shared use of directories, drives, or printers and the hardware costs are minimal. A network
can substantially simplify internet access for two or more people. Of course another reason for setting up a
network is to play multiplayer games, such as World of Warcraft, or use "groupware" applications such as shared
calendars, contact lists, and to-do lists.
Configuring and connecting networking hardware
The standard networking technology used today is Ethernet. Ethernet works by means of adapters known as
Network Interface Cards (NICs) in each computer. The NICs are connected with cables which vary depending on
the cabling option chosen. Many recent computers have built-in network capability on the motherboard.
Ethernet comes in two flavors. Fast Ethernet operates at 100 or 1000 Megabits per second (Mbps) and is overkill
for a SOHO network. Regular or original Ethernet operates at 10 Mbps which is fast enough for a small LAN.
NICs can be purchased to fit into a PCI slot or USB port, and can also be found to fit a laptop PCMCIA slot or
USB port.
There are two different Ethernet cabling options one of which will be usually used in any given LAN. NICs can be
purchased with any of these interface connectors or even with two connectors. If the NIC has more than one
connector a jumper plug or software configuration is usually used to select which connector is in use. Internal PCI
or external USB NICs cost as little as $20 each.
The older coaxial interface, also known as 10-base-2, or "thin", or "BNC" Ethernet works with a coaxial bayonet
"BNC" connector on the NIC. Computers are connected together in a "daisy chain" using BNC "T" adapters
plugged into each NIC. A coaxial 50 ohm cable connects each "T" to the "T" on the next computer. The first and
last computers will have a terminator resistor plugged into the unoccupied arm of the "T". Coaxial typically is only
available at the 10 megabit speed. Hubs and NICs that provide coaxial connectivity are much harder to find
nowadays, with the advent of inexpensive twisted-pair networking equipment.
The twisted pair interface, also known as "UTP" or 10-base-T or "RJ-45", has an RJ-45 jack on the NIC. The
RJ-45 connectors look similar to the standard telephone RJ-11 jack (but are somewhat larger) and are used with
cables that look similar to standard telephone twisted pair cables to connect the NICs to a "hub", high speed
modem, or router.
The hub has between 4 and 32 RJ-45 jacks. New office buildings are often wired with RJ-45 jacks in the walls to
facilitate setting up 10-base-T LANs. Hubs plug into a power line and cost $25 and up. Some hubs provide a BNC
connector as well as the RJ-45 jacks. Motels are increasingly providing RJ-45 connections for laptops.
You will need to use a residential router (like a Linksys, Belkin or D-Link) to establish IP addresses for each
computer in the network. Even wireless routers will have 3 or 4 wired RJ-45 jacks in the back of the unit. If you
need only that many wired connections in your SOHO network, you will not need to use an additional hub. If you
need more than 4 wired connections, connect a hub to your router using a cross-over RJ-45 network cable.
This will allow the two devices to communicate properly one with another.
Setting up network software
Ethernet transmits data by means of data packets, and the network automatically adjusts to adding more
computers to the environment. NICs all have a unique MAC address built in at the factory to facilitate this. After
you physically install your NIC you will need to install the driver for the NIC using Windows installation
procedures and disk supplied by your NIC manufacturer. Usually, diagnostic software and software to set up the
NIC regarding which connector to use (if it has more than one) is also supplied.
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Once you install the NIC driver, go to the Windows Control Panel and select the Network Connections
application. Right-click on the particular network connection, and then select the “Properties” option. Make sure
that client for Microsoft networks, your adapter driver, the TCP/IP protocol, and Microsoft file and printer sharing
for Microsoft networks service are installed. This is the default situation for a typical Windows installation. Under
file and print sharing check "give others access to my file" and "give others access to my printers" to enable both
file and printer sharing.
When the network is completed you can specify specific drives or directories to be shared with other computers
on your LAN. You can right-click on a drive shown in My Computer, and select the “Sharing and security" option
to enable file sharing. You can share individual directories or entire drives for read-only access or access with a
password. You can also specify printers to be shared. When directories, drives, or devices are shared you will
see a hand symbol attached to the icon for that item.
Groupware
Although you can share files so that any computer on the LAN can open the same file on the same drive, there is
a complication. If more than one computer could open and change the same file simultaneously, the changes
from one person will be lost. Many applications such as Microsoft Word will not open a file that is already open on
someone else’s computer (unless data sharing is enabled for that file). Applications specifically designed for
collaboration ("groupware" or "work group applications") avoid this problem.
Peer and server networks
Networks of computers, all of which are used as work stations, are commonly known as "peer-to-peer" networks.
A server network requires an additional dedicated server machine, usually running expensive server operating
system software, and therefore may be less attractive in a SOHO context. When investigating groupware
applications, make sure to understand if a server and specific server software is required, or if the application can
run on a peer network.
How to set up a TCP/IP network
TCP/IP (or IP for short) is the de facto protocol standard for any kind of small or large network. Further, it is the
protocol used when connecting to the Internet. Each computer on the LAN needs to have its own IP address.
Your router will assign IP addresses to each PC automatically using DHCP (Dynamic Host Configuration
Protocol). You could assign IP addresses manually, but there is no significant benefit to doing so. Manually
assigned “static” IP addresses (ones that do not change) are only needed for IP-based printers, or if you are
running a public Internet website to which a URL (like www.cnn.com ) is tied to that unchanging IP address.
Connecting your local network to the Internet
You can connect your router directly to the public Internet connection provided by your Internet Service Provider
(ISP), such as Verizon or Comcast. The router will manage the data transmissions from all of your
privately-addressed computers on your network (with IP addresses beginning with 192.168) to the Internet, and
vice versa.
ISPs generally provide a single public Internet Protocol (IP) address to their customers. This IP address is
usually assigned dynamically at logon time, so that it can be reassigned to someone else when you log off. All of
the PCs on your private network will appear to the Internet to have the public IP address provided by your ISP.
Your router will handle all of the connectivity issues so that two or more people can have simultaneous Internet
access.
Depending on your situation, your public Internet connection will connect to a cable or DSL modem, and your
network’s router will connect to the DSL/cable modem. Newer routers have both of these functions built into a
single component, making connections easier to manage.
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Voice Over IP (VoIP) services
Inexpensive router boxes are now available to support voice over IP (VoIP) services provided by Vonage or other
Internet based telephone services. These units connect to the Internet via RJ-45 cable connecting to your
cable/DSL modem or router, and typically provide two RJ-11 phone connectors and three RJ-45 Ethernet
connectors. The Ethernet connectors can be connected directly to up to three computers. The phone connectors
can be connected to ordinary phones or fax machines to provide up to two lines of phone service.
The phone lines can be routed to many phones via standard building phone lines. However, these small VoIP
boxes may not be able to drive as many telephones or phone-connected devices as a typical telephone company
line. If you are using more than one phone or fax machine on each line, check with the box vendor to see how
many devices each line can handle.
The quality of the VoIP service is mostly dependent on the quality of the underlying Internet service. For
example: if you are having problems with Vonage, it is quite likely that the actual problem is the quality of the
connection provided by your cable or DSL supplier. If you are using a wired or wireless router, the VoIP box
should be connected to the DSL/cable modem, and the router then should be connected to the VoIP box. In this
way the VoIP box will have priority over the computer's access, and voice quality will be better during times when
your computers are accessing the Internet.
Be advised that fax machines can have problems with VoIP systems. This is because any momentary delay,
slowdown, or dropping of data packets can interfere with the operation of the analog modem in the fax, which can
cause a dropped fax error. If you are having problems faxing, try setting the fax's modem to operate at a slower
speed (9600 bps) instead of the normal 14,400 bps. Refer to the fax's instruction manual for directions on how to
modify this setting.
Also, Internet-based applications like Skype and ooVoo allow you to make VoIP calls between PCs, as well as to
cellular and land-line phones. Calls between PCs anywhere in the world are free, and calls from a PC to a cellular
or land-line phone cost approximately $0.02 per minute. These companies have monthly or pay-as-you-go plans,
plans that provide you with a traditional telephone number, and a full range of calling services (like caller ID,
automatic redial, call forwarding, voice mail, and so forth). Visit these companies’ websites for additional
information on the programs and available plans and features.
Managing modems and routers
Cable modems, DSL modems, and routers typically have a built-in web server that displays configuration pages.
By entering the IP address of the device in your browser (usually 192.168.1.1), you can browse to the device’s
configuration page and setup the various operating parameters of the device. Also, your ISP can browse to your
router and assist you whenever you have connectivity problems.
Fiber Optic Services (FiOS)
Verizon is now offering high-speed fiber optic Internet services to their customers. Comcast, Cox, and other ISPs
nationally are also providing the same service. Fiber-optic cable provides extremely high bandwidth and
simultaneously can carry cable TV services, voice phone service, and high speed Internet on a single fiber. The
fiber comes to your house and connects to a box usually located inside the house, near where the outside
telephone interface box is located.
If you sign up for fiber-optic Internet service, Verizon will likely convert your phone service to fiber as well.
Companies like Verizon want you to switch because fiber is easier to maintain than the existing copper wires,
and they will have to maintain the fiber-optic service anyhow.
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The FiOS interface box has an UPS with a battery backup connected to it, so that telephone service can be
provided in event of a power failure. The batteries in these UPS systems reportedly only last for a few hours, so
you may want to have other telephone services available (like a cell phone) if you tend to have long power
outages.
Changing SSID on a SOHO network
A service set identifier (SSID) is a case sensitive, 32 alphanumeric character unique identifier attached to the
header of packets sent over a wireless local-area network (WLAN) that acts as a password when a mobile device
tries to connect to the basic service set (BSS) -- a component of the IEEE 802.11 WLAN architecture.
The SSID differentiates one WLAN from another, so all access points and all devices attempting to connect to a
specific WLAN must use the same SSID to enable effective roaming. As part of the association process, a
wireless client must have the same SSID as the one put in the access point or it will not be permitted to join the
BSS.
Manufacturers set a default SSID for their routers at the factory, generally using the same name for each. Linksys
routers, for example, all typically start with an SSID of "linksys." To improve the security of your network, you
should consider changing its SSID.
Log in to the router's administrative console through a Web browser using the default password and username.
Linksys routers, for example, typically have the Web address http://192.168.1.1/, the username admin and a
blank password. In the router's administrative console, navigate to the appropriate wireless settings section
where the SSID can be changed. Choose a suitable network name and enter it as in the example shown below.
An SSID is case sensitive and has a maximum length of 32 alphanumeric characters. The new SSID is not
activated on the router until you save or confirm the change. Click the Save Settings button at the bottom of the
page; you will see a confirmation window appear briefly to confirm the change was made successfully. The new
SSID will take effect immediately; rebooting the router typically is not required.
Disabling SSID Broadcast on your router
When a wireless device searches the area for wireless networks, it will detect the SSID to be able to associate
with the router. By default, SSID Broadcast is enabled; however, you may also choose to disable it.
Disabling the SSID Broadcast is one way of securing your wireless network. This will prevent other users from
detecting your SSID or your wireless network name when they attempt to view the available wireless networks in
your area.
To disable the SSID Broadcast on a Linksys router (for example), access the router’s web-based setup page at
the address 192.168.1.1. Click on the Wireless tab and set the SSID Broadcast to Disabled. If the Configuration
View is set to Wi-Fi Protected Setup, set that feature to Manual and then select Disabled for SSID Broadcast.
Save your settings; the router may restart during this process.
Enable MAC filtering on your router
Most Wi-Fi access points and routers ship with a feature called hardware or MAC address filtering. This feature is
normally turned "off" by the manufacturer, because it requires a bit of effort to set up properly. However, to
improve the security of your Wi-Fi LAN (WLAN), strongly consider enabling and using MAC address filtering.
Without MAC address filtering, any wireless client can join (authenticate with) a Wi-Fi network if they know the
network name (also called the SSID) and perhaps a few other security parameters like encryption keys. When
MAC address filtering is enabled, however, the access point or router performs an additional check on a different
parameter. Obviously the more checks that are made, the greater the likelihood of preventing network break-ins.
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To set up MAC address filtering, you as a WLAN administrator must configure a list of clients that will be allowed
to join the network. First, obtain the MAC addresses of each client from its operating system or configuration
utility. Then, they enter those addresses into the configuration screen of the wireless access point or router.
Finally, switch on the filtering option.
Once enabled, whenever the wireless access point or router receives a request to join with the WLAN, it
compares the MAC address of that client against the administrator's list. Clients on the list authenticate as
normal; clients not on the list are denied any access to the WLAN.
MAC addresses on wireless clients can't be changed as they are burned into the hardware. However, some
wireless clients allow their MAC address to be "impersonated" or "spoofed" in software. It's certainly possible for
a determined hacker to break into your WLAN by configuring their client to spoof one of your MAC addresses.
Although MAC address filtering isn't bulletproof, still it remains a helpful additional layer of defense that improves
overall Wi-Fi network security.
Do not confuse MAC address filtering with content filtering. Content filtering on a wireless access point or router
allows administrators to maintain a list of Web site URLs or addresses that should not be accessed from the
home WLAN.
Changing the router default username and password
As mentioned on the previous page, most routers used on SOHO networks ship with a default username and
password combination. This makes it easy for hackers potentially to break into your router (and network) and
wreak havoc. Resetting the password will make your router far more secure. Simply log into your router’s
configuration page, and click on the Administration tab. You will see a dialog box where you can change the
password from the default to a new password of your choosing. Save your settings when completed.
Low RF signal, radio power levels, and antenna and access point placement
The location of your wireless router or wireless access point makes a huge difference in how your system will
perform. Be sure to place the router in the most central location in the home or office, so that the radio signal will
propagate throughout the entire structure. 802.11n routers will have the best signal strength and data transfer
speeds, while 802.11g routers will perform at a slower speed, and 802.11b routers will be even slower and
transmit less of a signal.
Newer 802.11n routers will have the ability to vary the signal strength that is broadcast from the device. This
signal strength adjustment can be made from the router configuration page. In all cases, make sure that the
router’s antennas are extended fully and are not being blocked by walls or solid metal objects. Also make sure
that any other devices that could create radio frequency interference (CB radios, wireless intercom systems,
microwave ovens) are located at least 10 feet away from the router.
With USB wireless network interface cards installed on a desktop PC, you may find the network performance or
data transfer speeds are compromised because the device is connected in the back of the PC, probably under a
desk and near a wall. Use a USB extension cable to connect the wireless USB NIC to the PC, and then move the
device around until you get an optimal signal from the wireless router.
A 802.11g or 802.11n wireless router should be able to broadcast through at least 2 levels of a house, to a
distance of at least 50 – 75 feet. If your performance is not satisfactory, refer to the documentation for your router,
contact your router manufacturer for information and assistance, or contact your Internet service provider for
guidance.
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Disabling ports on your SOHO router
As mentioned earlier in this chapter, TCP/IP and UDP networks use ports (endpoint to a logical connection) as a
way to allow client programs to specify a specific server program on a computer in a network. Some ports have
numbers that are preassigned to them. Port numbers range from 0 to 65536, but only ports numbers 0 to 1024
are reserved for privileged services and designated as well-known ports.
Knowing the correct port numbers will enable you to trouble-shoot connection problems or failures, especially if a
TCP/IP port has been closed or disabled by a router. In some cases, you will want either open or close a port to
allow (or block) an Internet-capable program from passing data over the Web.
Begin by making a list of which applications you plan on allowing or blocking. Some may be connected with
games, streaming content or peer-to-peer sites, such as LimeWire. These are items that can slow down an
Internet connection, make your network vulnerable to hackers, decrease workplace productivity or result in illegal
activity. Find out which port each blocked program uses. Every software package has its own unique port
requirements as well as different ways of determining which port it uses, but in virtually every case you can find
this information in the "Preferences" settings of the application. Look for any "Network" or "Advanced" settings in
the program's preferences to find which port is required.
Log onto your router’s configuration page. Select the "Port Range Forwarding" option from under the
"Applications & Gaming" tab on from the configuration page. Enter the name of the application in the
"Application" field, and the starting and ending port numbers in the appropriate fields, as many applications use a
range of consecutive numbers for the port number. If your application uses only one port number (for example,
iChat on a Mac uses port 5190), then input the same number in both the "Start" and the "End" fields.
Click on the "Save" button at the bottom of the window to save any changes you have made. Make sure your
changes have taken effect by testing an application.
Enabling/disabling the Windows Firewall
All SOHO routers come equipped with a firewall application. This firewall can be enabled or disabled on the
router configuration page, like many other features of the device.
Even if this router-based firewall is enabled, the author recommends that all end-user PCs enable the Windows
Firewall application. This provides the user with additional safety and security when accessing the Internet.
The Windows Firewall can be enabled (or disabled) from the Windows Firewall Control Panel application, and
also from the Security Center Control Panel application.
Assigning static IP addresses, IP conflicts, limited or intermittent connectivity
Typically a home or an office computer will obtain a dynamically-assigned IP address through DHCP from their
router or DHCP server. There are instances when a computer (called a host on the Internet) will have a static,
unchanging IP address assigned to it. For example, if a computer is hosting a website, it will need a static IP
address that then can be associated to the URL and web domain name.
However, if two (or more) computers on a network have the same IP address, one computer (the first one to
connect and be recognized on the network) will operate properly, and the other computer will not be able to
connect. It is important to keep good records of what computers have been assigned static IP addresses, and
what addresses have been assigned to them. This will reduce the likelihood of connection problems in the future.
Also, if a computer cannot be assigned an IP address (i.e., the DHCP server failed to deliver an address to the
client), the computer may be seen on the network, but have no access to network resources or the Internet.
Running both the IPCONFIG /release and then IPCONFIG /renew commands from the command prompt
should resolve this problem, by forcing the system to assign the computer a valid IP address.
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What is an APIPA address?
Short for Automatic Private IP Addressing, APIPA is a feature of later Windows operating systems. With APIPA,
DHCP clients can automatically self-configure an IP address and subnet mask when a DHCP server isn't
available. When a DHCP client boots up, it first looks for a DHCP server in order to obtain an IP address and
subnet mask. If the client is unable to find the information, it uses APIPA to automatically configure itself with an
IP address from a range that has been reserved especially for Microsoft.
The IP address range is 169.254.0.1 through 169.254.255.254. The client also configures itself with a default
class B subnet mask of 255.255.0.0. A client uses the self-configured IP address until a DHCP server becomes
available.
The APIPA service also checks regularly for the presence of a DHCP server (every five minutes, according to
Microsoft). If it detects a DHCP server on the network, APIPA stops, and the DHCP server replaces the APIPA
networking addresses with dynamically assigned addresses.
APIPA is meant for use with non-routed small business environments, usually with less than 25 clients.
Subnet masks
A subnet mask is a number that defines a range of IP addresses that can be used in a network. Subnet masks
are used to designate sub-networks, or subnets, which are typically local networks LANs that are connected to
the Internet. Systems within the same subnet can communicate directly with each other, while systems on
different subnets must communicate through a router. Therefore, sub-networks can be used to partition multiple
networks and limit the traffic between them.
A subnet mask hides, or "masks," the network part of a system's IP address and leaves only the host part as the
machine identifier. A common subnet mask for a Class C IP address is 255.255.255.0. Each section of the
subnet mask can contain a number from 0 to 256, just like an IP address.
Therefore, in the example above, the first three sections are full, meaning the IP addresses of computers within
the subnet mask must be identical in the first three sections. The last section of each computer's IP address can
be anything from 0 to 255. For example, the IP addresses 10.0.1.201 and 10.0.1.202 would be in the same
subnet, while 10.0.2.201 would not. Therefore, a subnet mask of 255.255.255.0 allows for close to 256 unique
hosts within the network (since not all 256 IP addresses can be used).
If your system is connected to a network, you can typically view the network's subnet mask number in the
Network control panel in Windows, or System Preferences in the Mac OS X. Most home networks use the default
subnet mask of 255.255.255.0. However, some office networks may use a different subnet mask such as
255.255.255.128, which can be used to split a network into two subnets.
Large networks with several thousand machines may use a subnet mask of 255.255.0.0. This is the default
subnet mask used by Class B networks. The largest Class A networks use a default subnet mask of 255.0.0.0.
Wake-on-LAN
Wake-on-LAN (WoL) is an industry standard protocol for waking computers up from a very low power mode
remotely. “Low power mode” means that the computer is “off” but it still has access to a power source. The
protocol also allows for a supplementary Wake-on-Wireless-LAN ability as well.
WoL is dependent on two things: your motherboard and your network card. Your motherboard must be
connected to an ATX-compatible power supply. Your Ethernet or wireless card must also support this
functionality. Because it is set either through the BIOS or through your NIC’s firmware, you don’t need specific
software to enable it.
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WoL-enabled computers wait for something called a “magic packet” to arrive that includes the NIC’s MAC
address in it. These magic packets are sent out by software applications made for various platforms, but they
also can be sent by routers and internet-based websites. The typical ports used for WoL magic packets are UDP
ports 7 and 9. Because your computer is actively listening for a packet, some power is feeding your network card.
On laptop computers, this can drain your laptop’s battery somewhat.
Magic packets are usually sent over the entirety of a network and contain the subnet information, network
broadcast address, and the MAC address of the target computer’s network card, whether Ethernet or wireless.
Many motherboard manufacturers often implement software along with WoL capabilities to offer
configuration-free operation. Most motherboards have the WoL settings within the system BIOS. Check your
system’s documentation to find the location within the Setup program to configure WoL.
Quality of Service (QoS)
Quality of Service or QoS is a method of providing improved connectivity for selected traffic types over various
types of packet-switched networks. The network medium used could be any one of several types of technology
ranging from Ethernet to Wireless and Frame Relay networks. QoS provides a method for determining which
traffic should be given priority on a network segment.
An example of an environment that uses QoS would be an Internet based phone system on an organization’s
network. Suppose an organization creates a packet-switched network with 20 computers using Ethernet as the
backbone. The company then connects a router and other hardware to connect to the public Internet.
QoS does not really become affected by this scenario, because all of the traffic is of primarily the same type.
When the company decides to attach a new telephone system to their network using Voice Over IP technology,
QoS will become a factor.
The primary function of QoS is to ensure that all technologies are getting the bandwidth they need to function at
a desired level. In this case, the telephones would be getting enough bandwidth to prevent choppy calls and the
computers would be getting enough bandwidth to surf the Internet and perform duties to avoid seeming slow to
their users.
Remote Desktop Connection
Remote Desktop is a function included with Windows XP Professional and above. It enables you to connect to
your computer across the Internet from virtually any computer or Internet-capable device. Unlike a typical VPN
connection that gives a remote PC access to the company network, Remote Desktop allows you to see and
control your connected PC as though you were sitting directly in front of it.
To start the Remote Desktop Connection to another computer, click on the following Start menu options:
Start > All Programs > Accessories > Remote Desktop Connection
Once the program loads, enter the path to your Remote Desktop PC into the Computer field and hit the Connect
button. You then will be connected to the remote PC. You will have to specify certain things to ensure you get
connected to the desired PC; these include:
Computer Name: The Computer Name value on a networked computer helps Windows to identify specific
computers on a local network. You can use this only when you are on the same network as the Remote Desktop
computer; this will not work if you are connecting from a computer outside your home or office. You can find this
value on a computer by right-clicking the My Computer or Computer icon on your desktop or the Start menu,
clicking Properties, and if in Windows XP, you need to click the Computer Name tab.
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Local IP Address: This number (such as 192.168.1.103) also helps identify computers on a local network, and it
is used by the network components when sending and receiving data. Like with the Computer Name; you can
use this only when you are on the same network. You can find a computer's IP address by looking through the
network connection status details in Windows.
Internet IP Address: This number is the IP address of your Internet connection (DSL or FiOS router, cable
modem), assigned by your Internet service provider (ISP), used to identify computers or networks on the Web.
Use this IP address when connecting to your Remote Desktop PC if you are away from the home or office. You
can find your Internet IP address on your router's status pages, under the WAN or Internet section, or you can
Google it to be detected by a Web site service. Note that your Internet IP will likely change, anywhere from daily
to monthly, if you have a dynamic IP address. This type of address is typical on most residential, and even small
business, Internet connections. Contact your ISP to see if you have a dynamic IP address or a static address.
Domain or Host Name: If you have a dynamic IP address, you can use a domain or host name to connect to
your Remote Desktop PC. This requires signing up for a service (like DynDNS, FreeDNS.afraid.org, and No-IP),
and you will have to configure your router with your account details. This will ensure your host name will stay
updated when your IP address changes.
If you followed the directions to set up Web access of your Remote Desktop PC, you should now be able to
access your computer via a Web browser. Open your Web browser, enter the URL, and hit the Enter key. The
URL will look like this:
http://YourIPAddress:PortYouChoose/tsweb/
If you are connecting to the Remote Desktop from a computer on the local network, you can use the PC's local IP
address rather than the Internet IP address. If you are connecting from elsewhere, you must use your Internet IP
address.
If you are prompted to install the Remote Desktop ActiveX control, click Yes. On the Remote Desktop Web
Connection page click Connect.
Some tips to remember when using Remote Desktop Connection:

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
Your PC must be plugged in and turned on to remotely connect to it. Disable any automatic sleep,
hibernation, or stand-by features on your PC.
Keep Windows up-to-date with critical and recommended updates to make sure you're protected.
Make sure the Windows Firewall, or another third-party solution, is always on and protecting against
hackers.
Even when you connect to a PC via the Web browser, the host computer must also have the traditional
Remote Desktop feature enabled.
Proxy servers and proxy settings
A proxy server negotiates the transfer of data between a client application, such as a Web browser, and another
server on the network or Internet. The proxy server intercepts all requests to that server and determines if it can
fulfill the requests itself. If it cannot do so, it forwards the request to the networked or Internet server.
Proxy servers fulfill two main purposes:
Improve network performance: Proxy servers can dramatically improve performance for groups of users. This
is because it saves the results of all requests for a certain amount of time. Consider the case where two users
access the World Wide Web through a proxy server. The first user requests a certain Web page, and sometime
later the second user requests the same page. Instead of forwarding the request to the Web server where that
page resides, the proxy server delivers the same page that it already retrieved for the first user.
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Since the proxy server is often on the same network as the user, the user will see faster network delivery of
requested data. Proxy servers can support hundreds or thousands of users. Major online services such as
Google, Bing and Yahoo, for example, will use an array of proxy servers to speed performance.
Filter Requests: Proxy servers also are used to filter requests. For example, a company might use a proxy
server to prevent its employees from accessing specific Web sites.
You can set the proxy server values (IP address, default port) within the LAN Settings dialog box within your web
browsers. Be sure to remove the proxy server values in this dialog box if the computer is used on some other
network. Otherwise, your browser will not be able to retrieve the information for which you are looking.
Users and groups (Administrator, Power User, User, Guest, Standard User)
On higher-level versions of Windows operating systems (i.e., Windows Vista Business or Ultimate version, as
compared to Vista Home Basic or Home Premium), there are five types of user accounts:





Administrators have complete and unrestricted access to the computer/domain,
Backup operators can override security restrictions for the sole purpose of backing up or restoring files
Power users possess most administrative powers with some restrictions. Power users cannot install or
uninstall applications, or install/uninstall device drivers.
Users are prevented from making accidental or intentional system wide changes
Guests have the same access as members of the users group by default, except for the Guest account
which is further restricted.
On some versions of Windows, there are only two user account types (excluding the Guest user account):
Computer administrator account
The computer administrator account is intended for someone who can make system-wide changes to the
computer, install software, and access all non-private files on the computer. Only a user with a computer
administrator account has full access to other user accounts on the computer. A user with a computer
administrator account:




Can create and delete user accounts on the computer.
Can change other users' account names, pictures, passwords, and account types.
Cannot change his or her own account type to limited unless there is at least one other user with a
computer administrator account. This ensures that there is always at least one user with a computer
administrator account on the computer.
Can manage his or her network passwords, create a reset password disk, and set up his or her account to
use a .NET Passport.
Standard User / Limited account
The standard user / limited account is intended for someone who should be prohibited from changing most
computer settings and deleting important files. A user with a limited account:




Generally cannot install software or hardware, but can access programs that have already been installed
on the computer.
Can change his or her account picture and can also create, change, or delete his or her password.
Cannot change his or her account name or account type. A user with a computer administrator account
must make these kinds of changes.
Can manage his or her network passwords, create a reset password disk, and set up his or her account to
use a .NET Passport.
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When you create a new user account on a Windows PC or a Windows domain server, you can select the type of
user account that person will have. The best practice is to give the minimum level of rights needed in order for the
person to work effectively.
User rights can further be controlled through the use of Group Policy Objects (GPOs) on Windows domain-based
network. These GPOs can control issues such as password length and complexity, number of days until the
password expires, hours during which the user can log into the network, and so forth. A network administrator will
develop and deploy GPOs on your network.
User account creation and assignment into a user type group can be done through the User Accounts Control
Panel application, or from the Users and Groups portion of the Microsoft Management Console (MMC). On a
domain-based network, the Active Directory Users and Computers application wil let you create, modify or delete
user accounts on that network. Any rights assignments made for the network will be passed down to the
end-user's computer as well.
Networking tools (punch down tool, crimper, tester, loopback plug, toner probes, wire stripper)
You will use a variety of tools when making cables or checking connections on a network. These tools include:





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
A punch down tool, also called a krone tool, is a small hand tool used by telecommunication and network
technicians. It is used for inserting wire into insulation-displacement connectors on punch down blocks,
patch panels, keystone modules, and surface mount boxes (also known as biscuit jacks).
A crimping tool connects cable connectors to the cable media (twisted-pair cable, coaxial cable).
A cable tester determines if the twisted-pair (CAT-5, CAT-5E, CAT-6) cable is wired correctly.
A loopback plug is a device used to test ports (such as serial, parallel USB and network ports) to identify
network and network interface card (NIC) issues. Loopback plug equipment facilitates the testing of
simple networking issues and is available at very low costs. A loopback plug device is classified as male
or female. A loopback plug is also known as a loopback adapter or loopback cable.
A tone probe is an electronic test instrument to help trace wires. One part (the tone generator) induces a
tone on a pair of wires, and with the other you part (the tone probe) you can detect the tone at the other
end to trace where the wires go. You can trace wires through walls using a tone probe, and determine
which pair is carrying the signal you induced at the other end.
A wire stripper removes the external wrapper of a twisted-pair or coaxial cable and exposes the wires so
that the proper cable connectors (CAT-5, BNC) can be attached.
A wi-fi analyzer scans for available wireless networks at your location, and shows the relative signal
strength for each available router.
NTFS vs. share permissions
NTFS file permissions on a local hard drive allow the user to have the following kinds of rights:


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

Full Control: Change permissions and take ownership, plus perform the actions permitted by all other
NTFS file permissions
Modify: Modify and delete the file plus perform the actions permitted by the Write permission and the
Read & Execute permission
Read & Execute: Run applications plus perform the actions permitted by the Read permission
Read: Read the file, and view file attributes, ownership, and permissions
Write: Overwrite the file, change file attributes, and view file ownership and permissions
Share permissions can be implemented on NTFS and FAT file systems for shared resources, such as file folders
or printers. Available permissions include Read, Change and Full Control. Permissions are also implemented
with the Samba application, so that you can access Unix/Linux systems.
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Home vs. work vs. public network settings
When connecting to a wireless network, Windows Vista, Windows 7 and Windows 8 will ask the user during the
connection process what kind of network is being connected to. A home or a work network is considered to be
secure, and the Windows Firewall will take that into account during the connection session. A public network is
deemed to be less secure, and the Windows Firewall will take a more proactive security approach when it comes
to browsing the Web, downloading or uploading files, and so forth.
The user should accurately select the proper type of network during the wireless connection process. This should
prevent any problems with unauthorized browsing attempts to that computer, or with attacks from various kinds
of malicious software.
File attributes
Traditionally, in DOS and Microsoft Windows operating systems, files and folders have four different attributes:




Archive: When set, it indicates that the hosting file has changed since the last backup operation.
Windows' file system sets this attribute on any file that has changed. Backup software then has the duty
of clearing it upon a successful backup.
Hidden: When set, indicates that the hosting file is hidden. MS-DOS commands like dir and Windows
apps like File Explorer do not show hidden files by default, unless asked to do so.
System: When set, indicates that the hosting file is a critical system file that is necessary for the computer
to operate properly. MS-DOS and Microsoft Windows use it to mark important system files. MS-DOS
commands like dir and Windows apps like File Explorer do not show system files by default even when
hidden files are shown, unless asked to do so.
Read-only: When set, indicates that a file should not be altered. Upon opening the file, file system API
usually does not grant write permission to the requesting application, unless the application explicitly
requests it. Read-only attributes on folders are usually ignored.
As new versions of Windows came out, Microsoft has added to the inventory of available attributes on the NTFS
file system, including but not limited to:



Compressed: When set, Windows compresses the hosting file upon storage.
Encrypted: When set, Windows encrypts the hosting file upon storage to prevent unauthorized access.
Indexed: When set, Indexing Service or Windows Search do not include the hosting file in their indexing
operation.
Client-side virtualization
A client-based virtual machine is an instance of an operating system that is managed centrally on a server and
executed locally on a client device. Although the operating system disk image is updated and backed up by
synchronizing regularly with a server, a constant network connection is not necessary for a client-based virtual
machine to function.
A client-based virtual machine can run without a host operating system directly on a type 1 (or bare-metal)
hypervisor, or at the same time as a host operating system, utilizing a type 2 hypervisor. The hypervisor provides
an interface to the local hardware, taking the place of drivers that would normally be contained in an operating
system image. This allows virtual machine images to be standardized and usable across a large variety of
different hardware configurations.
Many businesses and Federal agencies use virtualization solutions to allow employees to telework, rather than
having to come into the office for some portion of their work week. Employees can telework using desktop or
laptop computers, Macs, tablets, or other Internet-capable devices (like smartphones).
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However, in order to enable more advanced functionality, virtual machines must often reach through the
hypervisor and interact with the local host hardware directly. This requires the virtual machine to have specific
drivers for the hardware on which it is running, negating the benefits of a standardized image. Despite this
drawback, many benefits of centralized management remain, including the ability to easily back-up, secure,
encrypt, and repair disk images.
Resource requirements for client-side virtualization
Different types of software require specific amounts of available resources to install and then provide optimal
performance. If resources are insufficient, the software and the operating system will take more time for
processing data and performance may suffer. Virtual machine applications allow you to allocate memory
sufficient for proper operation. You also can control settings that determine how much of the host computer's
CPU resources shall be available to the virtual machine.
Emulator requirements
Virtual machine applications can emulate, or make something look and work like, another type of computer.
For example, a Windows-based virtual desktop can be run in a window on an iPad or Android tablet. In
addition to the hardware requirements needed for client-side virtualization, the virtualization application needs
to be able to emulate the required software environment on a number of different hardware platforms.
Network requirements
People using virtualized environments must be able to log into and authenticate to the host system. Further,
unauthorized individuals need to be kept out of the secure systems. Many organizations using virtualized
desktop solutions will use two-factor authentication to ensure that only authorized persons can access the
resources. In addition to a username and password combination, users may need to enter a PIN number and
an RSA passcode (for example) from a hardware token or RSA smartphone application in order to login. The
passcode number on these tokens change every 60 seconds, to ensure that only authorized persons can log
into the system.
Security requirements
Virtualized environments need to have security built into the applications, to ensure that hackers cannot gain
access to what could potentially be restricted environments. Applications like Citrix and VMware use both 128bit encryption and Layer 2 Tunneling Protocol (L2TP) to keep virtual sessions secure.
Major vendors of desktop (client-side) and server virtualization solutions include Citrix and VMWare. You can
obtain more information about virtualization solutions by visiting the websites listed below:
Citrix: http://www.citrix.com/
VMWare: http://www.vmware.com/
NOTES
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OVERVIEW OF RESIDENTIAL AND COMMERCIAL BROADBAND INTERNET SYSTEMS
A residential gateway is a home networking device, used as a gateway to connect devices in the home to the
Internet or other WAN.
It is an umbrella term, used to cover multi-function networking computer appliances used in homes, which may
combine a DSL modem or cable modem, a network switch, providing LAN switching, a consumer-grade router,
and a wireless access point. In the past, such functions were provided by separate devices, but by technological
convergence, they have often merged into a single device.
There are multiple devices that have been described as "residential gateways" each with a different function.
Each type of device allows the connection of a LAN (used in the home) to a WAN. The WAN can be often the
Internet or can merely be a larger LAN of which the home is a part (such as a municipal WAN that provides
connectivity to the residences within the municipality). WAN connectivity may be provided through DSL, cable
modem, a broadband mobile phone network, or other connections.
The term "residential gateway" was originally used to distinguish the inexpensive networking devices designated
for use in the home from similar devices used in corporate LAN environments (which generally offered a greater
array of capabilities). In recent years, however, the less expensive "residential gateways" have gained many of
the capabilities of corporate gateways and the distinctions are fewer. Many home LANs now are able to provide
most of the functions of small corporate LANs.
Therefore the term "residential gateway" was becoming obsolete and merely implies a less expensive, lower
capability networking device.
Nowadays, the home gateway tends to have abundant interfaces, powerful functions and a more user-friendly
interface. It is a manageable terminal with auto-configuration, multiple interfaces, and multi-service perceiving
and bearing. Home gateways provide Quality of Service to bear on services of different types at the same time.
As a part of the carrier network, the home gateway shall support remote control, detection and configuration.
Devices for network and Internet connectivity
Multiple devices have been described as "residential gateways":
●
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●
●
●
●
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●
Cable modem
DSL or ADSL modem
Network modem
Router or Wireless router
Network switch
VoIP ATA
Wireless access point
or any combination of the above.
A typical router provides:
●
●
●
●
●
IP address routing
network address translation (NAT)
DHCP functions
firewall functions
LAN connectivity like a Network switch
Most routers are self-contained components, using internally-stored firmware. They are generally
OS-independent (i.e. can be used with any operating system). Most also have a firewall application built into
them, giving the users additional protection from hackers.
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Wireless routers perform the same functions as a router, but also allows connectivity for wireless devices with the
LAN, or between the wireless router and another wireless router. (The wireless router-wireless router connection
can be within the LAN or can be between the LAN and a WAN.)
A modem (e.g. DSL modem, Cable modem) provides none of the functions of a router. It merely allows Ethernet
traffic to be transmitted across telephone lines, cable wires, optical fibers, or wireless radio frequencies. On the
receiving end is another modem that re-converts the transmission format back into digital data packets.
This allows network bridging using telephone, cable, optical, and radio connection methods. The modem also
provides handshake protocols, so that the devices on each end of the connection are able to recognize each
other. However, a modem generally provides few other network functions.
●
●
A USB modem plugs into a single PC and allow connection of that single PC to a WAN. If properly
configured, the PC can also function as the router for a home LAN.
An internal modem can be installed on a single PC (e.g. on a PCI card), also allowing that single PC to
connect to a WAN. Again, the PC can be configured to function as a router for a home LAN.
A wireless access point can function in a similar fashion to a modem. It can allow a direct connection from a
home LAN to a WAN, if a wireless router or access point is present on the WAN as well.
Features
Beyond basic connectivity and routing, residential gateways can provide addition features, such as:
●
●
Configuration via a web interface (by browsing to 192.168.1.1)
Dynamic DNS, which is a service that lets anyone on the Internet gain access to resources on a local
network when the Internet address of that network is constantly changing. Such resources are typically a
Web server, webcam or a PC for remote control operation.
Manufacturers
There are a number of manufacturers of networking devices that have been used as residential gateways Here is
a list of some of the more well-recognized manufacturers:
3Com
Allied Telesis
Apple Inc. (termed AirPort Base Stations)
Asus
Belkin
Check Point
D-Link
Enterasys Networks
Linksys
Motorola
NEC
NETGEAR
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Siemens AG
SMC Networks
U.S. Robotics
Verizon
Westell Technologies, Inc.
Zoom Telephonics
ZyXEL
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Configuring typical residential / small-business routers
Virtually all residential routers can be configured by using a browser such as Internet Explorer or Mozilla Firefox.
By pointing to the internal IP address for the router and entering the username and password combination, one
can access the router and setup various features, such as:
●
●
●
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●
WPA and/or WEP encryption
MAC address filtering
NAT translation
Opening or closing TCP/IP ports that are used by devices such as an Xbox, PlayStation 3, or a smart phone
(such as a BlackBerry, iPhone or Droid)
Setting the channel frequency for the wireless router (to prevent conflicts with cordless phones)
Lease times for private IP addresses
Public DNS and WINS server addresses
Cloning a PC’s MAC address (primarily required on Comcast systems)
Most routers have their private IP address set to 192.168.1.1; some will be set at 192.168.0.1. To access the
router, launch your browser application, and instead of entering a typical URL (like www.bbcnews.com ), enter
the IP address for the router. An authentication window will appear; enter the router’s administrator username
and password combination. Here are some typical combinations to use:
Linksys and Westell: username is blank, and password is admin (lowercase)
D-Link and Belkin: username is Admin (case-sensitive), and password is password (lowercase)
Other brands: try the username of admin (lowercase) and a password of admin or password (lowercase)
If the router has a username and password combination that is unknown, there is a reset button at the back of the
unit that can be used to clear the passwords and reset the router to default settings. Press the button with a
paperclip or very small screwdriver. Pressing the reset button while the unit is powered will perform a “warm
boot” that will restart the router, but not clear the password or other settings. Removing power from the router,
holding in the reset button and then restoring power to the router will force a “cold boot” reset of the unit. Hold the
button in for several seconds after restoring power, and then release the button. The router will then revert back
to the out-of-box default settings. Refer to the manufacturer’s instructions when working with your router.
If the user wishes to enable the WPA (Wi-fi Protected Access) or WEP (wired equivalent privacy) protocols, you
will need to develop a “pass-phrase” password that can be remembered and provided to any wireless devices
attempting to connect to the router. Here are the key differences between WEP and WPA:
WEP aims to provide security by encrypting data over radio waves so that it is protected as it is transmitted from
one end point to another. However, it has been found that WEP is not as secure as once believed. WEP is used
at the two lowest layers of the OSI model - the data link and physical layers; it therefore does not offer end-to-end
security.
WPA technology is designed to work with existing Wi-Fi products that have been enabled with WEP (i.e., as a
software upgrade to existing hardware), but the technology includes two improvements over WEP:
●
●
Improved data encryption through the temporal key integrity protocol (TKIP). TKIP scrambles the keys using
a hashing algorithm and, by adding an integrity-checking feature, ensures that the keys haven’t been
tampered with.
User authentication, which is generally missing in WEP, through the extensible authentication protocol
(EAP). WEP regulates access to a wireless network based on a computer’s hardware-specific MAC
address, which is relatively simple to be sniffed out and stolen. EAP is built on a more secure public-key
encryption system to ensure that only authorized network users can access the network.
WPA was replaced by WPA2 as the official, recognized networking standard by the IEEE in 2011.
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When developing a WEP or WPA pass-phrase, you will need to create a password that has a combination of
numbers, letters and special characters. In this way you can be assured that the password is sufficiently complex
and will prevent hackers from easily obtaining access to the wireless router.
You should connect a PC to the router via the wired connections at the back of the device when setting the
WPA or WEP pass-phrase. That way, you will not lose the connection to the router when the pass-phrase initially
is established. Write down the pass-phrase, and keep it in a secure location. You can view the pass-phrase in the
router’s configuration program from a PC connected via a hard-wired connection, but not while connected
wirelessly.
Comcast systems and cloning PC MAC addresses
Comcast has a business practice of allowing only ONE computer per household to be connected to their cable
modem systems at a time. Comcast records the Media Access Control (MAC) address from the “authorized” PC’s
network card, and only allows that one MAC address to interact with their system. Most residential routers now
are designed to overcome this problem by “cloning” the MAC address of the authorized wired PC. This will allow
multiple PCs to connect simultaneously to the Internet on a Comcast system.
To accomplish this, start by connect the PC directly to the cable modem, and run the Comcast Internet
configuration software application. Once that PC is running properly on the system, disconnect the PC from the
cable modem. Attach the cable modem to the “Internet” jack on the router, and connect a PC to the router with a
CAT-5 network cable. Access the router’s configuration page with your browser software, and navigate to the
“Clone PC MAC address” menu option. Clone the PC’s MAC address, save the settings, and allow the router to
restart. You may also need to reboot the PC for the changes to take effect.
If you have difficulty with this process, contact the router manufacturer, rather than Comcast technical support.
Most router manufacturers are familiar with this procedure, and they can step you through the process.
Router failures
Like any other electronic device, routers and cable modems will fail or become defective. A number of reasons
can account for this problem:
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Overheating (most routers are not heat-sinked, and do not have cooling fans)
Electrical damage from surges (from the AC line or the incoming phone/cable line)
AC adapter failure
Hacking (some hackers are bright enough to know how to wipe the router ROM BIOS)
Breakage from falls
Other forms of consumer abuse (spilling liquids, rough treatment, etc.)
If a residential or small-office router fails, the best and simplest solution is to replace the unit. The cost of
residential routers continue to drop, even as performance on newer routers increases. If you have performed a
warm and/or cold-boot to a router and it fails to connect properly, and you know the incoming Internet connection
is live (because you connected a PC or laptop directly to the incoming cable and got onto the Internet), purchase
a new router and replace the old one.
Differences between 802.11b, 802.11g and 802.11n wireless connections
There are three different wireless transmission protocols in use today: 802.11b, 802.11g, and 802.11n. Each of
these protocols have different transmission speeds and security characteristics. These protocols are described
starting on the next page:
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802.11b
Also referred to as 802.11 High Rate or Wi-Fi, the 802.11b protocol is an extension to the original 802.11
specification developed by the IEEE for wireless LAN (WLAN) technology that applies to wireless LANs. It
provides 11 Mbps transmission (with a fallback to 5.5, 2 and 1 Mbps) in the 2.4 GHz band. 802.11b uses only
direct-sequence spread spectrum (DSSS), which is a transmission technology where a data signal at the
sending station is combined with a higher data rate bit sequence, or chipping code, that divides the user data
according to a spreading ratio. If one or more bits in the pattern are damaged during transmission, the original
data can be recovered due to the redundancy of the transmission. 802.11b was a 1999 ratification to the original
802.11 standard, allowing wireless functionality comparable to Ethernet.
802.11g
802.11g is an extension to 802.11 specification developed by the IEEE for wireless LAN (WLAN) technology that
is used for transmission over short distances at up to 54-Mbps in the 2.4 GHz bands. 802.11g routers typically
have greater data transmission ranges than do 802.11b routers, usually in the range of 200 - 250 feet from the
source.
802.11n
802.11n is an extension to 802.11 specification developed by the IEEE for wireless LAN (WLAN) technology.
802.11n builds upon previous 802.11 standards by adding multiple-input multiple-output (MIMO). The additional
transmitter and receiver antennas allow for increased data throughput through spatial multiplexing and increased
range by exploiting the spatial diversity through coding schemes like Alamouti coding. The data transmission
speed is 100 Mbit/s (even 250 Mbit/s in PHY level), and so up to 4-5 times faster than 802.11g. 802.11n also
offers a better operating distance than current networks.
Compatibility issues
An 802.11n router typically will be backwardly compatible with 802.11b and 802.11g devices; 802.11g routers
will recognize 802.11b devices, but not the newer 802.11n interface cards. When selecting a new router, try to
purchase one that has the highest and best data transmission capabilities. This will provide the consumer with
the most satisfactory wireless online experience. When working with an existing router, examine the unit or
access the configuration page to determine which of these three protocols are supported.
Residential wireless routers and residential cordless phones
One of the biggest reported problems with residential wireless routers is that the connections will sporadically
terminate for what appears to be no reason. In fact, there is a very simple reason: wireless routers transmit data
at the same frequency spectrum as residential cordless phones. These devices work at the 2.4GHz and/or
5.8GHz frequency bands, and each bandspread has 11 separate channels. If your cordless phone is operating at
the same frequency and channel as your wireless router, you will suffer a disconnection from the router
whenever the telephone rings.
The solution to this problem is quite simple: change the channel. Cordless phones have a “channel” button that
will rotate the phone to an alternate channel within the spectrum. Simply press the channel button once, and your
phone will now be at a different frequency than your router. However, if your neighbor is the person with the
cordless phone at the offending frequency, you will have to change channels on the router. Access the router
configuration page, and navigate to the options to change the channel frequency. The router typically will restart
after such a change, and you may need to reboot the PC or laptop to re-establish the wireless connection.
This problem even has been reported with some models of garage-door opener units. The fix for this problem is
the same as with a cordless phone: change the radio channel of one of these devices, and the issue will be
resolved.
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Mobile broadband and 3G / EV-DO wireless Internet access
Evolution-Data Optimized (EV-DO) is a fast wireless broadband access (3G) technology, where you are
the hotspot (meaning you don't need a Wi-Fi hotspot to have the Internet access). Your PC or laptop
requires a EV-DO PC card for connection. EV-DO supports an "always-on" connection, similar to DSL.
EV-DO is the wireless broadband standard that has been adopted by many CDMA mobile phone service
providers, such as Cricket, Verizon, and Sprint/Nextel. AT&T and T-Mobile have similar products that
work in the GSM cellular radio frequencies.
Mobile broadband adapters essentially are cellular phones that only permit data access to the provider’s
network resources. So long as there is a cell tower within range, the customer can access the Internet at
speeds that come close to residential-based wired Internet systems. Adapters can be purchased from the
cellular carriers for existing PCs and laptops, along with monthly or contract-based access plans. Many
new laptops and netbook PCs have 3G and/or EV-DO adapters pre-installed in them.
Some providers (Sprint, for example) have created mobile wi-fi hotspots that essentially are EV-DO
modems which permit up to five PCs or laptops to connect to the mobile broadband connection. So long
as the laptop or other device has traditional wi-fi capabilities, these devices can tap into the bandwidth
available on the mobile hotspot’s EV-DO modem.
WiMAX and 4G mobile broadband Internet access
WiMAX is the next-generation of wireless technology designed to enable pervasive, high-speed mobile
Internet access to the widest array of devices including notebook PCs, handsets, smartphones, and
consumer electronics such as gaming devices, cameras, camcorders, music players, and more. As the
fourth generation (4G) of wireless technology, WiMAX delivers low-cost, open networks and is the first all
IP mobile Internet solution enabling efficient and scalable networks for data, video, and voice. As a major
driver in the support and development of WiMAX, Intel has designed embedded WiMAX solutions for a
variety of mobile devices supporting the future of high-speed broadband on-the-go.
WiMAX is based upon the IEEE 802.16e standard enabling the delivery of wireless broadband services
anytime, anywhere. WiMAX products can accommodate fixed and mobile usage models. The IEEE
802.16e standard was developed to deliver non-line-of-sight (LoS) connectivity between a subscriber
station and base station with typical cell radius of three to ten kilometers.
WiMAX technology utilizes Orthogonal Frequency-Division Multiplexing (OFDM) over EDGE, GPRS, and
HSPA cellular frequencies to deliver higher bandwidth efficiency and therefore higher data throughput,
with more than one Mbps downstream and higher data rates. This allows more than one frequency (or
signal) at a time to be used in delivering data streams over the wireless/cellular spectrum to the customer.
Adaptive modulation also increases link reliability for carrier-class operation and the possibility to keep
higher order modulation at wider distance extend full capacity over longer distances.
As of May 2009, the WiMAX Forum is tracking 475 network deployments in 140 countries. You can visit
WiMAX Maps at www.wimaxmaps.org to see where these systems are being deployed. WiMAX Maps is
an interactive WiMAX deployment mapping database provided by WiMAX Forum and powered by
Informa Telecoms & Media’s World Cellular Information Service (WCIS) using the Google Maps API.
Locally, the company called Clear provides 4G/WIMAX throughout the eastern portion of the United
States, and is building their nationwide network at this time. WiMAX also is used throughout many parts
of the world, particularly in rural areas of Africa.
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Definitions of common networking terms
Listed below is a group of terms you will need to know in order to pass the networking segment of the A+
examination. Additional definitions are found in Chapter 15 of this book.
10Base2
One of several adaptations of the Ethernet (IEEE 802.3) standard for Local Area Networks (LANs). The
10Base-2 standard (also called Thinnet) uses 50 ohm coaxial cable (RG-58 A/U) with maximum lengths
of 185 meters. This cable is thinner and more flexible than that used for the 10Base-5 standard. The
RG-58 A/U cable is both less expensive and easier to place.
Cables in the 10Base-2 system connect with BNC connectors. The Network Interface Card (NIC) in a
computer requires a T-connector where you can attach two cables to adjacent computers. Any unused
connection must have a 50 ohm terminator.
The 10Base-2 system operates at 10 Mbps and uses baseband transmission methods.
10BaseT
One of several adaptations of the Ethernet (IEEE 802.3) standard for Local Area Networks (LANs). The
10Base-T standard (also called Twisted Pair Ethernet) uses a twisted-pair cable with maximum lengths of
100 meters. The cable is thinner and more flexible than the coaxial cable used for the 10Base-2 or
10Base-5 standards.
Cables in the 10Base-T system connect with RJ-45 connectors. A star topology is common with 12 or
more computers connected directly to a hub or concentrator.
The 10Base-T system operates at 10 Mbps and uses baseband transmission methods.
100BaseT
A networking standard that supports data transfer rates up to 100 Mbps (100 megabits per second).
100BASE-T is based on the older Ethernet standard. Because it is 10 times faster than Ethernet, it is
often referred to as Fast Ethernet. Officially, the 100BASE-T standard is IEEE 802.3u.
Like Ethernet, 100BASE-T is based on the CSMA/CD LAN access method. There are several different
cabling schemes that can be used with 100BASE-T, including:
100BASE-TX: two pairs of high-quality twisted-pair wires
100BASE-T4: four pairs of normal-quality twisted-pair wires
100BASE-FX: fiber optic cables
AFP
The Apple Filing Protocol (AFP), formerly AppleTalk Filing Protocol, is a proprietary network protocol
that offers file services for Mac OS X and original Mac OS. In Mac OS X, AFP is one of several file
services supported, with others including Server Message Block (SMB), Network File System (NFS),
File Transfer Protocol (FTP), and WebDAV. AFP currently supports Unicode file names, POSIX and
access control list permissions, resource forks, named extended attributes, and advanced file locking. In
Mac OS 9 and earlier, AFP was the primary protocol for file services.
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Airplane mode
Airplane mode is a setting on cell phones, smartphones and other mobile devices that prevents the
device from sending or receiving calls and text messages. Airplane mode is also known as offline mode,
standalone mode and flight mode.
ATM
ATM is short for Asynchronous Transfer Mode, a network technology based on transferring data in cells
or packets of a fixed size. The cell used with ATM is relatively small compared to units used with older
technologies. The small, constant cell size allows ATM equipment to transmit video, audio, and computer
data over the same network, and assure that no single type of data hogs the line.
Current implementations of ATM support data transfer rates of from 25 to 622 Mbps (megabits per
second). This compares to a maximum of 100 Mbps for Ethernet, the current technology used for many
LANs.
ATM creates a fixed channel, or route, between two points whenever data transfer begins. This differs
from TCP/IP, in which messages are divided into packets and each packet can take a different route from
source to destination. This difference makes it easier to track and bill data usage across an ATM network,
but it makes it less adaptable to sudden surges in network traffic.
When purchasing ATM service, you generally have a choice of four different types of service:
Constant Bit Rate (CBR) specifies a fixed bit rate so that data is sent in a steady stream. This is
analogous to a leased line.
Variable Bit Rate (VBR) provides a specified throughput capacity but data is not sent evenly. This is a
popular choice for voice and videoconferencing data.
Unspecified Bit Rate (UBR) does not guarantee any throughput levels. This is used for applications, such
as file transfer, that can tolerate delays.
Available Bit Rate (ABR) provides a guaranteed minimum capacity but allows data to be bursted at higher
capacities when the network is free.
ARP
Once a common encapsulation mechanism has been selected for Ethernet, hosts must still convert a
32-bit IP address into a 48-bit Ethernet address. The Address Resolution Protocol (ARP), documented in
RFC 826, is used to do this. It has also been adapted for other media, such as FDDI.
ARP works by broadcasting a packet to all hosts attached to an Ethernet. The packet contains the IP
address the sender is interested in communicating with. Most hosts ignore the packet. The target
machine, recognizing that the IP address in the packet matches its own, returns an answer.
Hosts typically keep a cache of ARP responses, based on the assumption that IP-to-hardware address
mapping rarely change.
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ARP Bridging and Routing
ARP is transparent to bridging, since bridging will propagate ARP broadcasts like any other Ethernet
broadcast, and will transparently bridge the replies.
A router does not propagate Ethernet broadcasts, because the router is a Network Level device, and
Ethernet is a Data Link Level protocol. Therefore, an Internet host must use its routing protocols to select
an appropriate router, that can be reached via Ethernet ARPs.
After ARPing for the IP address of the router, the packet (targeted at some other Destination Address) is
transmitted to the Ethernet address of the router.
Proxy ARP
Proxy ARP is a technique that is can be used by routers to handle traffic between hosts that don't expect
to use a router as described above. Probably the most common case of its use would be the gradual
subnetting of a larger network. Those hosts not yet converted to the new system would expect to transmit
directly to hosts now placed behind a router.
A router using Proxy ARP recognizes ARP requests for hosts on the "other side" of the router that can't
reply for themselves. The router answers for those addresses with an ARP reply matching the remote IP
address with the router's Ethernet address (in essence, a lie).
Proxy ARP is best thought of as a temporary transition mechanism, and its use should not be encouraged
as part of a stable solution. There are a number of potential problems with its use, including the inability of
hosts to fall back on alternate routers if a network component fails, and the possibility of race conditions
and bizarre traffic patterns if the bridged and routed network segments are not clearly delineated.
Baseband transmission
The original band of frequencies of a signal before it is modulated for transmission at a higher frequency.
The signal is typically multiplexed and sent on a carrier with other signals at the same time.
Bluetooth
Bluetooth is a short-range radio technology aimed at simplifying communications among Internet devices
and between devices and the Internet. It also aims to simplify data synchronization between Internet
devices and other computers. Bluetooth signals typically travel between devices at a distance no more
than 10 meters maximum, and usually no more than 1 meter (three feet).
Products with Bluetooth technology must be qualified and pass interoperability testing by the Bluetooth
Special Interest Group prior to release. Bluetooth's founding members include Ericsson, IBM, Intel, Nokia
and Toshiba.
Bridge
A bridge is a device that connects two local-area networks (LANs), or two segments of the same LAN. The
two LANs being connected can be alike or dissimilar. For example, a bridge can connect an Ethernet
with a Token-Ring network.
Unlike routers, bridges are protocol -independent. They simply forward packets without analyzing and
re-routing messages. Consequently, they're faster than routers, but also less versatile.
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Broadband transmission
A type of data transmission in which a single medium (wire) can carry several channels at once. Cable
TV, for example, uses broadband transmission. In contrast, baseband transmission allows only one
signal at a time. Broadband signals can be transmitted by coaxial cable, fiber optic cable, satellite and
cellular communications.
Most communications between computers, including the majority of local-area networks, use baseband
communications. An exception is an older B-ISDN network, which employs broadband transmission.
Brouter
Short for bridge router, a brouter functions as both a router and a bridge. A brouter understands how to
route specific types of packets, such as TCP/IP packets. Any other packets it receives are simply
forwarded to other network(s) connected to the device (this is the bridge function).
CAT3, CAT5, CAT5e, CAT6, CAT6e and CAT7 cable
CAT is short for the word “category”; each of these categories of twisted pair cables have different datacarrying capacities. For example, CAT5 cable can safely transmit 10megabits per second (10Mbps),
CAT5e can transmit 100Mbps, CAT6 can transmit up to 1000Mbps, or a Gigabit per second. CAT5 and
CAT6 cables can transmit data up to 100 meters, or 330 feet. CAT7 cable can transmit data further than
CAT6 cables, and the “e” designations indicate that the cables have additional shielding to prevent
signal loss or distortion.
CIDR
Classless Inter-Domain Routing (CIDR) is a method for allocating IP addresses and routing Internet
Protocol packets. CIDR is implemented in order to slow the growth of routing tables on routers across
the Internet, and to help slow the rapid exhaustion of IPv4 addresses.
Coaxial cable
Coaxial cable, or coax, is a type of cable that has an inner conductor surrounded by a tubular insulating
layer, surrounded by a tubular conducting shield. Many coaxial cables also have an insulating outer
sheath or jacket. The term coaxial comes from the inner conductor and the outer shield sharing a
geometric axis. Coaxial cable differs from other shielded cable used for carrying lower-frequency
signals. The dimensions of the cable are controlled to give a precise, constant conductor spacing,
which is needed for it to function efficiently as a transmission line. RG-6 cable has two layers of
shielding, and RG-59 cable has a single layer of shielding.
CSU/DSU
CSU/DSU is short for Channel Service Unit/Data Service Unit. The CSU is a device that performs
protective and diagnostic functions for a telecommunications line. The DSU is a device that connects a
terminal to a digital line. Typically, the two devices are packaged as a single unit. You can think of it as a
very high-powered and expensive modem. Such a device is required for both ends of a T-1 or T-3
connection, and the units at both ends must be set to the same communications standard.
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Dial-up networking
Dial-up networking enables you to connect your computer to a network or the Internet via a modem. If
your computer is not connected to a LAN and you want to connect to the Internet, you need to configure
Dial-Up Networking (DUN) to dial a Point of Presence (POP) connection, and log into your Internet
Service Provider (ISP). Your ISP will need to provide certain information, such as the gateway address
and your computer's IP address.
Dial-up networking is quickly being phased out of existence, as the presence of fast, cheap and widely
available broadband connections grows throughout the world. Unless you have no other way to connect
to the Internet, dial-up networking should be avoided, because of its comparatively slow performance.
Digital Subscriber Line (DSL)
DSL refers collectively to all types of digital subscriber lines, the two main categories being ADSL and
SDSL. Two other types of xDSL technologies are High-data-rate DSL (HDSL) and Very high DSL
(VDSL). Most are just referred to by the term DSL, for short.
DSL technologies use sophisticated modulation schemes to pack data onto copper wires. They are
sometimes referred to as last-mile technologies because they are used only for connections from a
telephone switching station to a home or office, not between switching stations.
xDSL is similar to ISDN inasmuch as both operate over existing copper telephone lines (POTS) and both
require the short runs to a central telephone office (usually less than 20,000 feet). However, xDSL offers
much higher speeds - up to 32 Mbps for upstream traffic, and from 32 Kbps to over 1 Mbps for
downstream traffic.
Ethernet over Power (or Power-line communications), and Power over Ethernet
Power-line communication (PLC) is a communication protocol that uses electrical wiring to
simultaneously carry both data, and Alternating Current (AC) electric power transmission or electric
power distribution. It is also known as power-line carrier, power-line digital subscriber line (PDSL),
mains communication, power-line telecommunications, or power-line networking (PLN).
A wide range of power-line communication technologies are needed for different applications, ranging
from home automation to Internet access which is often called broadband over power lines (BPL).
Most PLC technologies limit themselves to one type of wire (such as premises wiring within a single
building), but some can cross between two levels (for example, both the distribution network and
premises wiring). Typically transformers prevent propagating the signal, which requires multiple
technologies to form very large networks. Various data rates and frequencies are used in different
situations.
By comparison, Power over Ethernet (PoE) describes any of several standardized or ad-hoc systems
which pass electrical power along with data on Ethernet cabling. This allows a single cable to provide
both data connection and electrical power to devices such as wireless access points or IP cameras.
Unlike standards such as Universal Serial Bus which also power devices over the data cables, PoE
allows long cable lengths. Power may be carried on the same conductors as the data, or it may be
carried on dedicated conductors in the same cable.
PoE is often used to place wireless routers or access points in locations where an electrical outlet is
not nearby, and where running such an electrical line is cost-prohibitive or otherwise not possible.
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Fiber Optic cable
Fiber optic cable uses glass (or plastic) threads (fibers) to transmit data. A fiber optic cable consists of a
bundle of glass threads, each of which is capable of transmitting messages modulated onto light waves.
Fiber optics has several advantages over traditional metal communications lines:
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Fiber optic cables have a much greater bandwidth than metal cables. This means that they can
carry more data.
Fiber optic cables are less susceptible than metal cables to interference.
Fiber optic cables are much thinner and lighter than metal wires.
Data can be transmitted digitally (the natural form for computer data) rather than analogically.
The main disadvantage of fiber optics is that the cables are expensive to install. In addition, they
are more fragile than wire and are difficult to splice.
Fiber optics is a particularly popular technology for local-area networks. In addition, telephone companies
are steadily replacing traditional telephone lines with fiber optic cables. In the near future, almost all
communications will employ fiber optics.
There are three types of fiber-optic cable connectors that are mentioned in the A+ examination: SC,
ST, and LC. SC, or Standard Connectors, have a snap (push-pull) coupling. ST, or Straight Tip
connectors have a bayonet, screw-on connector. LC, or Lucent Connectors, are a snap-on style of
connector.
The picture below shows the differences between the connector types mentioned above.
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FDDI
FDDI stands for Fiber Distributed Data Interface, a set of ANSI protocols for sending digital data over fiber
optic cable. FDDI networks are token-passing networks, and support data rates of up to 100 Mbps (100
million bits) per second. FDDI networks are typically used as backbones for wide-area networks.
An extension to FDDI, called FDDI-2, supports the transmission of voice and video information as well as
data. Another variation of FDDI, called FDDI Full Duplex Technology (FFDT) uses the same network
infrastructure but can potentially support data rates up to 200 Mbps.
Frame relay
Frame relay is a packet-switching protocol for connecting devices on a Wide Area Network (WAN).
Frame Relay networks in the U.S. support data transfer rates at T-1 (1.544 Mbps) and T-3 (45 Mbps)
speeds. In fact, you can think of Frame Relay as a way of utilizing existing T-1 and T-3 lines owned by a
service provider. Most telephone companies now provide Frame Relay service for customers who want
connections at 56 Kbps to T-1 speeds. (In Europe, Frame Relay speeds vary from 64 Kbps to 2 Mbps.
In the U.S., Frame Relay is quite popular because it is relatively inexpensive. However, it is being
replaced in some areas by faster technologies, such as ATM.
Hotspot
A hot spot (or hotspot) is a wireless LAN (local area network) node that provides Internet connection
and virtual private network (VPN) access from a given location. For example, a business traveller with
a laptop equipped for Wi-Fi can look up a local hot spot, contact it, and get connected through its
network to reach the Internet and their own company remotely with a secure connection. Increasingly,
public places, such as airports, hotels, and coffee shops are providing free wireless access for
customers.
Hub
A hub is a common connection point for devices in a network. Hubs are commonly used to connect
segments of a LAN. A hub contains multiple ports. When a packet arrives at one port, it is copied to the
other ports so that all segments of the LAN can see all packets.
A passive hub serves simply as a conduit for the data, enabling it to go from one device (or segment) to
another. So-called intelligent hubs include additional features that enables an administrator to monitor the
traffic passing through the hub and to configure each port in the hub. Intelligent hubs are also called
manageable hubs.
A third type of hub, called a switching hub (or simply a “switch”), actually reads the destination address of
each packet and then forwards the packet to the correct port.
ICMP
Short for Internet Control Message Protocol, an extension to the Internet Protocol (IP) defined by RFC
792. ICMP supports packets containing error, control, and informational messages. The PING command,
for example, uses ICMP to test an Internet connection between two networked devices.
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ISDN
ISDN stands for Integrated Services Digital Network, an international communications standard for
sending voice, video, and data over digital telephone lines or normal telephone wires. ISDN supports
data transfer rates of 64Kbps (64,000 bits per second). Most ISDN lines offered by telephone companies
give you two lines at once, called B channels. You can use one line for voice and the other for data, or you
can use both lines for data to give you data rates of 128 Kbps, three times the data rate provided by
today's fastest modems.
The original version of ISDN employs baseband transmission. Another version, called B-ISDN, uses
broadband transmission and is able to support transmission rates of 1.5 Mbps. B-ISDN requires fiber
optic cables and is not widely available. ISDN has essentially become obsolete with the advent of DSL
services from the telephone companies.
MAC Address filtering
MAC Filtering (or EUI filtering, or layer 2 address filtering) refers to a security access control methodology
whereby the 48-bit address assigned to each network card is used to determine access to the network.
MAC addresses are uniquely assigned to each card, so using MAC filtering on a network permits and
denies network access to specific devices through the use of blacklists and whitelists. While the
restriction of network access through the use of lists is straightforward, an individual person is not
identified by a MAC address, rather a device only, so an authorized person will need to have a whitelist
entry for each device that he or she would use to access the network.
While giving a wireless network some additional protection, MAC Filtering can be circumvented by
scanning a valid MAC (via the command airodump-ng) and then changing the own MAC into a validated
one. This can be done in the Windows Registry or by using command-line tools on a Linux platform.
MAU
MAU is short for Multi-station Access Unit (also abbreviated as MSAU), a token-ring network device that
physically connects network computers in a star topology while retaining the logical ring structure. One of
the problems with the token-ring topology is that a single non-operating node can break the ring. The
MAU solves this problem because it has the ability to short out non-operating nodes and maintain the ring
structure. A MAU is a special type of hub.
Multi-mode fiber optic cable
Multimode fiber optic cable has a large-diameter core and multiple pathways of light. It can be used for
most general data and voice applications, such as adding segments to an existing network.
Multimode comes in two core sizes and four varieties: 62.5-micron OM1, 50-micron OM2, 50-micron
OM3, and 50-micron OM4. (OM stands for optical mode.) All have the same cladding diameter of 125
microns, but 50-micron fiber cable has a smaller core (the light-carrying portion of the fiber). Although
all can be used in the same way, 50-micron cable, particularly laser-optimized OM3 and OM4 50micron cable, provides longer link lengths and/or higher speeds and is recommended for enterprise
applications (backbone, horizontal, and intra-building links) and should be considered for new
installations. OM3 and OM4 can also be used with LED and laser light sources.
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NAT and DNAT
Network address translation (NAT) is a static methodology of remapping one IP address space into
another by modifying network address information in Internet Protocol (IP) datagram packet headers
while they are in transit across a traffic routing device. The technique was originally used for ease of
rerouting traffic in IP networks without renumbering every host. It has become a popular and essential
tool in conserving global address space allocations in face of IPv4 address exhaustion.
Dynamic NAT (DNAT), just like static NAT, is not common in smaller networks but is found within larger
corporations with complex networks. The way dynamic NAT differs from static NAT is that where static
NAT provides a one-to-one internal to public static IP address mapping, dynamic NAT doesn't make the
mapping to the public IP address static and usually uses a group of available public IP addresses.
Repeater
A network device used to regenerate or replicate a signal. Repeaters are used in transmission systems to
regenerate analog or digital signals distorted by transmission loss. Analog repeaters frequently can only
amplify the signal while digital repeaters can reconstruct a signal to near its original quality.
In a data network, a repeater can relay messages between sub-networks that use different protocols or
cable types. Hubs can operate as repeaters by relaying messages to all connected computers. A
repeater cannot do the intelligent routing performed by bridges and routers.
RJ-11
Registered Jack-11 (RJ-11) connectors are four-wire connectors used for connecting traditional home
telephone equipment.
RJ-45
Short for Registered Jack-45, an eight-wire connector used commonly to connect computers onto a
local-area networks (LAN), especially Ethernet. RJ-45 connectors look similar to the ubiquitous RJ-11
connectors used for connecting telephone equipment, but they are somewhat wider.
Plenum cable
Cable that is run in the plenum spaces of buildings. In building construction, the plenum is the space that
is used for air circulation in heating and air conditioning systems, typically between the structural ceiling
and the suspended ceiling or under a raised floor. The plenum space is typically used to house the
communication cables for the buildings computer and telephone network(s). However, use of plenum
areas for cable storage poses a serious hazard in the event of a fire as once the fire reaches the plenum
space there are few barriers to contain the smoke and flames.
Plenum cable is coated with a fire-retardant coating (usually Teflon) so that in case of a fire it does not
give off toxic gasses and smoke as it burns. Twisted-pair and coaxial versions of cable are made in
plenum versions.
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Router
A router is a device that connects any number of LANs.
Routers use headers and a forwarding table to determine where packets go, and they use ICMP to
communicate with each other and configure the best route between any two hosts. Very little filtering of
data is done through routers. Routers do not care about the type of data they handle.
POP3
POP3 is short for Post Office Protocol 3, a protocol (or set of rules) used to retrieve e-mail from a mail
server. Most e-mail applications (sometimes called an e-mail client) use the POP protocol, although
some can use the newer IMAP (Internet Message Access Protocol).
There are two versions of POP. The first, called POP2, became a standard in the mid-80's and requires
SMTP to send messages. The newer version, POP3, can be used with or without SMTP.
PSTN or POTS
Short for Public Switched Telephone Network, which refers to the international telephone system based
on copper wires carrying analog voice data. This is in contrast to newer telephone networks base on
digital technologies, such as ISDN and FDDI. Telephone service carried by the PSTN is often called
“plain old telephone service” (POTS).
Single-mode fiber-optic cable
Single-mode cable (OS1, OS2) has a small (8–10-micron) glass core and only one pathway of light.
(OS stands for optical single-mode.) With only a single wavelength of light passing through its core,
single-mode realigns the light toward the core center instead of simply bouncing it off the edge of the
core as multimode does. OS1 is applied to inside-plant tight-buffered cable. OS2 is applied to loosetube cables.
Single-mode provides far greater distances than multimode cable and can go as far as 40 km so it’s
typically used in long-haul network links spread out over extended areas, including CATV and campus
backbone applications. Single-mode cable also provides higher bandwidth than multimode fiber.
SMB
Server Message Block (SMB), one version of which was also known as Common Internet File System,]
operates as an application-layer network protocol mainly used for providing shared access to files,
printers, and serial ports and miscellaneous communications between nodes on a network. It also
provides an authenticated inter-process communication mechanism. Most usage of SMB involves
computers running Microsoft Windows, where it was known as "Microsoft Windows Network" before the
subsequent introduction of Active Directory. Corresponding Windows services are LAN Manager Server
(for the server component) and LAN Manager Workstation (for the client component).
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SMTP
SMTP stands for Simple Mail Transfer Protocol, a protocol for sending e-mail messages between
servers. Most e-mail systems that send mail over the Internet use SMTP to send messages from one
server to another; the messages can then be retrieved with an e-mail client using either POP or IMAP.
In addition, SMTP is generally used to send messages from a mail client to a mail server. This is why you
need to specify both the POP or IMAP server and the SMTP server when you configure your e-mail
application.
SNMP
SNMP is short for Simple Network Management Protocol, a set of protocols for managing complex
networks. The first versions of SNMP were developed in the early 1980s. SNMP works by sending
messages, called protocol data units (PDUs), to different parts of a network. SNMP-compliant devices,
called agents, store data about themselves in Management Information Bases (MIBs) and return this
data to the SNMP requesters.
SNMP 1 reports only whether a device is functioning properly. The industry has attempted to define a
new set of protocols called SNMP 2 that would provide additional information, but the standardization
efforts have not been successful. Instead, network managers have turned to a related technology called
RMON that provides more detailed information about network usage.
Reverse ARP (RARP)
Reverse ARP, document in RFC 903, is a fairly simple bootstrapping protocol that allows a workstation to
broadcast using its Ethernet address, and expect a server to reply, telling it its IP address.
SSH
Secure Shell, or SSH, is a cryptographic (encrypted) network protocol to allow remote login and other
network services to operate securely over an unsecured network.
SSID
SSID is short for service set identifier, a 32-character unique identifier attached to the header of packets
sent over a WLAN that acts as a password when a mobile device tries to connect to the BSS. The SSID
differentiates one WLAN from another, so all access points and all devices attempting to connect to a
specific WLAN must use the same SSID.
A device will not be permitted to join the BSS unless it can provide the unique SSID. Because an SSID
can be sniffed in plain text from a packet it does not supply any security to the network.
An SSID is also referred to as a network name because it is a name that identifies a wireless network.
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STP
1) Acronym for Spanning Tree Protocol. STP, a link management protocol, is part of the IEEE 802.1
standard for media access control bridges. Using the spanning tree algorithm, STP provides path
redundancy while preventing undesirable loops in a network that are created by multiple active paths
between stations. Loops occur when there are alternate routes between hosts. To establish path
redundancy, STP creates a tree that spans all of the switches in an extended network, forcing redundant
paths into a standby, or blocked, state. STP allows only one active path at a time between any two
network devices (this prevents the loops) but establishes the redundant links as a backup if the initial link
should fail. If STP costs change, or if one network segment in the STP becomes unreachable, the
spanning tree algorithm reconfigures the spanning tree topology and reestablishes the link by activating
the standby path. Without spanning tree in place, it is possible that both connections may be
simultaneously live, which could result in an endless loop of traffic on the LAN.
2) Short for Shielded Twisted Pair cable, a popular type of cable that consists of 4 sets of two unshielded
wires twisted around each other, with a foil wrapper surrounding the cable. Due to its low cost, STP
cabling is used extensively for local-area networks (LANs) and telephone connections where signal loss
problems may exist.
T1 line
A T1 line is a dedicated phone connection supporting data rates of 1.544Mbits per second. A T-1 line
actually consists of 24 individual channels, each of which supports 64Kbits per second. Each
64Kbit/second channel can be configured to carry voice or data traffic. Most telephone companies allow
you to buy just some of these individual channels, known as fractional T-1 access.
T-1 lines are a popular leased line option for businesses connecting to the Internet and for Internet
Service Providers (ISPs) connecting to the Internet backbone. The Internet backbone itself consists of
faster T-3 connections.
T-1 lines are sometimes referred to as DS1 lines.
T3 line
A T3 line is a dedicated phone connection supporting data rates of about 43 Mbps. A T-3 line actually
consists of 672 individual channels, each of which supports 64 Kbps.
T-3 lines are used mainly by Internet Service Providers (ISPs) connecting to the Internet backbone and
for the backbone itself.
T-3 lines are sometimes referred to as DS3 lines.
Telnet
Telnet is a protocol which is used to establish a connection with a remote machine. For example, telnet
can be used to connect your PC to a Unix workstation via the Internet. With Telnet, you can work from
your PC as if it were a terminal physically attached to another machine. Windows has a Telnet client built
into the TCP/IP suite; click on Start, then Run, then type "Telnet" in the dialog box and click OK. You will
need to know the name of the remote computer, also called a host, in order to connect to it. Also, you will
need to have an account on the remote computer in order to begin a communications session.
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Tethering
Tethering is the process of using a cell phone or smartphone as a modem for a personal computer of
some sort - typically a laptop computer. The term gets its name from how a phone is attached, or
tethered, to the computer via a USB cable, but wireless technologies such as Bluetooth can also be
used for tethering.
Typically the network carrier and the user's account (contract) have to support tethering before it can be
used. Many networks charge an additional fee for users that wish to connect their phones as tethered
modems because it typically uses far more data than using the phone normally would.
UDP
UDP stands for User Datagram Protocol, which is a connectionless protocol that, like TCP, runs on top of
IP networks. Unlike TCP/IP, UDP/IP provides very few error recovery services, offering instead a direct
way to send and receive datagrams over an IP network. It is used primarily for broadcasting messages
over a network, or for streaming audio/video over the Internet.
uPnP
Universal Plug and Play (UPnP) is a set of networking protocols that permits networked devices, such
as personal computers, printers, Internet gateways, Wi-Fi access points and mobile devices to
seamlessly discover each other's presence on the network and establish functional network services
for data sharing, communications, and entertainment. UPnP is intended primarily for residential
networks without enterprise-class devices.
UTP
Short for Unshielded Twisted Pair, a popular type of cable that consists of four pairs of two unshielded
wires twisted around each other. Due to its low cost, UTP cabling is used extensively for local-area
networks (LANs) and telephone connections. UTP cabling does not offer as high bandwidth or as good
protection from interference as coaxial or fiber optic cables, but it is less expensive and easier to work
with.
VoIP
Short for Voice over Internet Protocol, a category of hardware and software that enables people to use
the Internet as the transmission medium for telephone calls by sending voice data in packets using IP
rather than by traditional circuit transmissions of the PSTN (the publically-switched telephone network).
One advantage of VoIP is that the telephone calls over the Internet do not incur a surcharge beyond what
the user is paying for Internet access, much in the same way that the user doesn't pay for sending
individual e-mails over the Internet. Skype and NetMeeting are examples of applications that use VoIP
technology.
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WEP
Short for Wired Equivalent Privacy, a security protocol for wireless local area networks (WLANs) defined
in the 802.11b standard. WEP is designed to provide the same level of security as that of a wired LAN.
LANs are inherently more secure than WLANs because LANs are somewhat protected by the
physicalities of their structure, having some or all part of the network inside a building that can be
protected from unauthorized access. WLANs, which are over radio waves, do not have the same physical
structure and therefore are more vulnerable to tampering. WEP aims to provide security by encrypting
data over radio waves so that it is protected as it is transmitted from one end point to another. However, it
has been found that WEP is not as secure as once believed. WEP is used at the two lowest layers of the
OSI model - the data link and physical layers; it therefore does not offer end-to-end security.
WPA/WPA2
Short for Wi-Fi Protected Access, a Wi-Fi standard that was designed to improve upon the security
features of WEP. The technology is designed to work with existing Wi-Fi products that have been enabled
with WEP (i.e., as a software upgrade to existing hardware), but the technology includes two
improvements over WEP:
●
●
Improved data encryption through the temporal key integrity protocol (TKIP). TKIP scrambles the
keys using a hashing algorithm and, by adding an integrity-checking feature, ensures that the
keys haven’t been tampered with.
User authentication, which is generally missing in WEP, through the extensible authentication
protocol (EAP). WEP regulates access to a wireless network based on a computer’s hardwarespecific MAC address, which is relatively simple to be sniffed out and stolen. EAP is
built on a more secure public-key encryption system to ensure that only authorized network users
can access the network.
WPA was replaced by WPA2 as the official, recognized networking standard by the IEEE in 2011.
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Wireless networking
Wireless networking falls under the 802.11 standard laid down by the Institute of Electrical and
Electronics Engineers (IEEE). Within the 802.11 wireless networking standard, there are several different
versions:
●
●
●
●
●
●
●
●
●
802.11 applies to wireless LANs and provides 1 or 2 Mbps transmission in the 2.4 GHz band
using either frequency hopping spread spectrum (FHSS) or direct sequence spread spectrum
(DSSS).
802.11a is an extension to 802.11 that applies to wireless LANs and provides up to 54-Mbps in
the 5GHz band. 802.11a uses an orthogonal frequency division multiplexing encoding scheme
rather than FHSS or DSSS.
802.11b (also referred to as 802.11 High Rate or Wi-Fi) C an extension to 802.11 that applies to
wireless LANS and provides 11 Mbps transmission (with a fallback to 5.5, 2 and 1-Mbps) in the
2.4 GHz band. 802.11b uses only DSSS. 802.11b was a 1999 ratification to the original 802.11
standard, allowing wireless functionality comparable to Ethernet.
802.11e is a wireless draft standard that defines the Quality of Service (QoS) support for LANs,
and is an enhancement to the 802.11a and 802.11b wireless LAN (WLAN) specifications.
802.11e adds quality of service (QoS) features and multimedia support to the existing IEEE
802.11b and IEEE 802.11a wireless standards, while maintaining full backward compatibility with
these standards.
802.11g applies to wireless LANs and is used for transmission over short distances at up to
54-Mbps in the 2.4 GHz bands.
802.11n builds upon previous 802.11 standards by adding multiple-input
multiple-output (MIMO). The additional transmitter and receiver antennas allow for increased data
throughput through spatial multiplexing and increased range by exploiting the spatial diversity
through coding schemes like Alamouti coding. The real speed would be 100 Mbit/s (even 250
Mbit/s in PHY level), and so up to 4-5 times faster than 802.11g.
802.11r, also called Fast Basic Service Set (BSS) Transition, supports VoWi-Fi handoff
between access points to enable VoIP roaming on a Wi-Fi network with 802.1X
authentication.
802.1X is NOT to be confused with 802.11x (which is the term used to describe the family of 802.11
standards) 802.1X is an IEEE standard for port-based Network Access Control that allows
network administrators to restricted use of IEEE 802 LAN service access points to secure
communication between authenticated and authorized devices.
802.11ac is a wireless networking standard in the 802.11 family (which is marketed under the
brand name Wi-Fi), developed in the IEEE Standards Association process, providing highthroughput wireless local area networks (WLANs) on the 5 GHz band. The standard was
developed from 2011 through 2013 and approved in January 2014.
Wi-fi Analyzer
Wireless networks use specific channels within the wireless spectrum. An overcrowded wireless
channel results in decreased bandwidth and/or connectivity issues for your network. A wi-fi analyzer
will allow you to see what channels are in use and to identify the best channel to set on your router.
There are a number of wi-fi analyzer applications available for you to use on Apple and Android
smartphones, since smartphones have wi-fi capabilities.
NOTES
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The OSI Model
The OSI (Open Systems Interconnection) model defines in a theoretical way a networking framework for
implementing protocols in seven layers. Control is passed from one layer to the next, starting at
the application layer in one station, proceeding to the bottom layer, over the channel to the next
station and back up the hierarchy.
You need to know the basics of the OSI model for both the A+ and Network+ certification examinations.
Application (Layer 7)
This layer supports application and end-user processes. Communication partners are identified, quality
of service is identified, user authentication and privacy are considered, and any constraints on data
syntax are identified. Everything at this layer is application-specific. This layer provides application
services for file transfers, e-mail, and other network software services.
Presentation (Layer 6)
This layer provides independence from differences in data representation (e.g., encryption) by translating
from application to network format, and vice versa. This layer formats and encrypts data to be sent across
a network, providing freedom from compatibility problems. It is sometimes called the syntax layer.
Session (Layer 5)
This layer establishes, manages and terminates connections between applications. The session layer
sets up, coordinates, and terminates conversations, exchanges, and dialogues between the applications
at each end. It deals with session and connection coordination.
Transport (Layer 4)
This layer provides transparent transfer of data between end systems, or hosts, and is responsible for
end-to-end error recovery and flow control. It ensures complete data transfer.
Network (Layer 3)
This layer provides switching and routing technologies, creating logical paths, known as virtual circuits,
for transmitting data from node to node. Routing and forwarding are functions of this layer, as well as
addressing, internetworking, error handling, congestion control and packet sequencing.
Data Link (Layer 2)
At this layer, data packets are encoded and decoded into bits. It furnishes transmission protocol
knowledge and management and handles errors in the physical layer, flow control and frame
synchronization. The data link layer is divided into two sub-layers: The Media Access Control (MAC) layer
and the Logical Link Control (LLC) layer. The MAC sub-layer controls how a computer on the network
gains access to the data and permission to transmit it. The LLC layer controls frame synchronization, flow
control and error checking.
Physical (Layer 1)
This layer conveys the bit stream - electrical impulse, light or radio signal -- through the network at the
electrical and mechanical level. It provides the hardware means of sending and receiving data on a
carrier, including defining cables, cards and physical aspects.
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Dial-Up Networking issues [obsolete]
The next few pages of the text deal with issues you may encounter when connecting to the Internet via a
dial-up networking connection. Such dial-up connections allow you to gain access to other computers,
and also to the Internet.
Note that dial-up networking has become obsolete with the advent of broadband Internet connectivity. If
you encounter customers that still are using dial-up networking systems, encourage them strongly to
investigate and purchase a high-speed, broadband Internet connection. Most dial-up Internet service
providers are scaling back or shutting down their modem-based connection services.
Modem communication terminology
Here is a list of terms commonly used in conjunction with modems and dial-up networking.
BBS
Bulletin Board System. A BBS allows you to interact with another computer via your modem, allowing you
to send/receive electronic mail (e-mail), download & upload data, and access various kinds of programs.
There are free and pay-for-access BBS systems run by individuals located throughout the world. BBS
systems were the predecessors to larger on-line systems such as Compuserve, Prodigy, and America
On-Line which charged monthly usage fees.
BPS
Bits Per Second; the rate at which data is transferred via a modem; sometimes inaccurately called the
baud rate. Standard telephone modems generally available today transfer data at speeds up to 56,000
BPS. "Cable modems" and "DSL (digital subscriber line) modems" are generally network interface cards,
and not true modems; cable and/or DSL modems transmit up to 15Mbps.
CIDR
Classless Inter-Domain Routing (CIDR) is a method for allocating IP addresses and routing Internet
Protocol packets. CIDR is implemented in order to slow the growth of routing tables on routers across
the Internet, and to help slow the rapid exhaustion of IPv4 addresses.
Data transfer protocol
A means of checking to see that your data has been transferred correctly; Common transfer protocols
include XMODEM, YMODEM, KERMIT, COMPUSERVE B, and ASCII. Refer to the Glossary of Terms in
this text for further definitions of these data transfer protocols.
Download
Transferring data to your computer from the computer with which you are communicating.
Duplexing
Setting your data communications channel so that it carries data in 1 or 2 directions; half duplex allows
data to travel in 1 direction only; full duplexing allows data to go in both directions.
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Echo
The return of transmitted data to your screen.
Modem
A device that converts digital data to analog data that can be transmitted across a telephone line; the
receiving end converts analog data back to digital data. Modem stands for MOdulator-DEModulator.
Parity
A means of checking data at the modem level to assure that data has been transferred accurately. It
involves the addition of overhead bits to ensure that the total number of 1s in a grouping of bits is always
either even for even parity, or odd for odd parity. This permits detection of single errors. No parity means
that parity checking is not performed.
RS-232
The IEEE technical name for a serial port, either a 9-pin or 25-pin version.
Stop bits
The last bit after a word, used to indicate the end of the word. There are both start and stop bits before
and after each word. Stop bits can be 1 or 2 bits long, depending on how the user wants their
communications session to be. One type is no better than another. Unix systems typically use 7-bit words
and 2 stop bits, while PC communications applications use 8-bit words with 1 stop bit.
Terminal emulation
Making your PC operate like one of several fairly common types of data (dumb) terminals. Common
emulations include VT-52, VT-100, ANSI-BBS, IBM 3101, and Wyse 100. The actual terminals
themselves are now obsolete, but the ways in which they transmit data are still in use.
Upload
Transferring data from your computer to the computer with which you are communicating.
Words
A "word" can be 7 or 8 bits long, depending upon the user and how he/she wants their communications
session to be. One type is no better than another. Unix systems typically use 7-bit words in
communications sessions, while PC-based systems use 8-bit words.
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Browser software
Once you have connected to an Internet Service Provider (ISP), you will use some type of browser
software to navigate to different places on the Internet. The two main browsers available on the market
today are Microsoft's Internet Explorer, Microsoft Edge, Mozilla Firefox, Apple Safari, and other third-party
browsers such as Google Chrome or Opera. These applications allow you to browse through HTML
documents on the web, and they utilize hypertext links within the documents to take you to different
locations on the Internet once you click on the link.
Browsers can also tie into e-mail servers and newsgroup servers; usually your ISP will provide you with
the name of your Post Office Protocol 3 (POP3), Simple Mail Transport Protocol (SMTP) or Internet Mail
Access Protocol (IMAP) server, so that you can access your e-mail and or discussion groups with the
newsgroup part of the Internet.
Any of these browsers are available for download from the Internet; going to www.microsoft.com will
enable you to obtain the latest copy of Internet Explorer, and going to www.mozilla.com will allow you to
download the newest version of Mozilla Firefox.
Domain names
The Internet has been divided into various domains, so as to make it easier for people to find different
sites on the Internet. For example:
o
o
o
o
o
o
o
o
the .COM domain is for companies
the .MIL domain is for military sites
the .ORG domain is for non-profit organizations
the .GOV domain is for governmental entities
the .NET domain is for Internet-based companies
the .EDU domain is for educational institutions
the .INFO domain is for organizations providing information via the Web
the .BIZ domain is for companies and for-profit businesses
Internet website names, such as www.washingtonpost.com, are pseudonyms for websites with a static
(unchanging) IP address. Routers on the Internet have tables of information that resolve the domain
name for a web site to an IP address that can be reached on the Internet. Browser software can find
websites by IP address or by domain names.
Searching and finding things on the Internet
Browser software offers two distinct tools to help you locate information: Internet "search" tools and page
"find" tools. A search tool helps you locate information such as web pages and discussion group
messages that resides on the Internet network. A find tool locates particular words or phrases within the
page that you're currently viewing.
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To search for information over the Internet with a browser
1.
2.
3.
Click the Search button on the toolbar. This displays a page offering access to Internet search
engines and other search services. Select a search engine from the list ... a popular search site is
called Yahoo, and it's found at http://www.yahoo.com. The leading Internet search engine is
Google, and it can be found at http://www.google.com .
Follow the instructions on the search engine site. Typically, you will type in search text, click a
button, then wait for the engine to locate occurrences of the text among a database of web pages.
Examine the search results. These usually are presented as a list of links to pages containing the
text you requested.
To find information in the current page
1.
2.
3.
Open the Edit menu and choose Find in Page.
In the resulting dialog box, type the text you want to find, then click Find Next. Located text is
highlighted and, if necessary, the page scrolls to the text's position.
Click the Edit menu's Find Again item to search for more occurrences.
The Edit menus of the Bookmarks window and Message window have similar commands, Find in
Bookmarks and Find in Message, respectively.
Using a URL to identify page locations
To understand how a single page is kept distinct in a world of electronic pages, you should recognize its
URL, short for Uniform Resource Locator. Every page has a unique URL. Not only does each page have
a unique URL, but also each image and frame on a page. You can access a page, an image, or an
individual frame by supplying its URL.
A URL is text used for identifying and addressing an item in a computer network. In short, a URL provides
location information and your browser displays a URL in the location field.
Most often you don't need to know a page's URL because the location information is included as part of a
highlighted link; your browser already knows the URL when you click highlighted text, click a toolbar
button, or select a menu item. But sometimes you won't have a link and instead have only the text of the
URL (perhaps from a friend or a newspaper article).
To enter a URL
Type the URL directly into the location text field. Alternatively, you can choose Open Page from the File
menu and type the URL in the resulting dialog box.
By entering a page's URL, your browser can bring you the specified page just as if you had clicked a link.
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Here are some sample URLs:
http://www.google.com
ftp://ftp.hp.com/pub/
news:news.announce.newusers
http://academic.pgcc.edu/~wlloyd/rta
To identify URL components
Browsers use the URL text to find a particular item, such as a page, among all the computers connected
to the Internet. Within the URL text are components that specify the protocol, server, and pathname of an
item.
Notice in the URL below http://www.google.com/index.html
that the protocol is followed by a colon (http:), the server is preceded by two slashes (//www.google.com),
and each segment of the pathname (only one here) is preceded by a single slash (/index.html).
The first component, the protocol, identifies a manner for interpreting computer information. Many
Internet pages use HTTP (short for HyperText Transfer Protocol). Other common protocols you might
come across include file (also known as FTP, which is short for File Transfer Protocol), news (the protocol
used by Usenet discussion groups), and gopher (an alternative transfer protocol).
The second component, the server, identifies the computer system that stores the information you seek
(such as www.google.com). Each server on the Internet has a unique name that identifies the location of
the server.
The last component, the pathname, identifies the location of an item on the server. For example, a
pathname usually specifies the name of the file identifying the page (such as /welcome.html), possibly
preceded by one or more directory/folder names that contain the file (such as /home/welcome.html).
Some pathnames use special characters. If you are typing a URL into the location field, you will need to
enter the characters that exactly match the URL. For example, some pathnames contain the tilde
character (~), which designates a particular home directory on a server.
Using links to pages
A link is a connection from one page to another. You find a link by looking for one or more words
highlighted with color, underlining, or both in the content area of a page.
Images and icons with colored borders also can serve as links. A link within a page that contains frames
can be a connection that displays one or more new pages within frames, or an entirely new top-level page
replacing all frames.
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To use a link in a browser
1.
2.
3.
4.
Point the mouse cursor over a link. The URL location of the link appears in the status message
area at the bottom-left of the window.
Click once on the highlighted text, image, or icon. This transfers page content from a server
location to your location.
After you click a link, a small graphic will animate to show you that the transfer of the page to your
computer is in progress.
Examine the status message area and progress bar at the bottom of the window to receive
feedback about the progress of a transfer.
To identify followed and unfollowed links
An unfollowed link is a connection to a page that you have not yet viewed. By default, unfollowed links are
blue. A followed link is a connection to a page that you have viewed. By default, followed links are purple.
You can change the colors used to denote unfollowed and followed links; from the Edit menu, choose
Preferences, then select the Colors panel. If you have a black-and-white monitor, unfollowed and
followed links are highlighted only with underlining and not differentiated.
To stop a page transfer in progress
Click the Stop button. Alternately, you can stop a link's action by choosing Stop Loading from the Go
menu.
You can stop a transfer whenever the loading process takes longer than you like. This might happen if the
content of the page is large or if the server computer is sluggish. Sometimes the page specified by a link
just is not available. You will usually get a message if a connection was not made or a page not found.
Links to content inside pages
When you bring a page to your screen, you will see the whole page or, if the content is extensive, only a
portion. (Scroll bars let you see the rest.) Often the portion you see is the beginning of the page, but
sometimes a link brings you content from the page's middle or end.
A link can display a new page or display a different portion of the same page (in effect, automatically
scrolling for you). For example, the beginning of a page might include a table of contents that links each
chapter title to its respective content further down the page.
"Mailto" links and Internet addresses
Yet another kind of link does not display a page at all. A "mailto" link whose URL begins with mailto:
produces the Message Composition window for sending mail (with the recipient's address automatically
filled in).
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Whereas a URL identifies a server's page location on the Internet, an Internet address identifies a user's
mailbox location. Here are the components of the Internet address aname@aserver.com:
o
o
o
aname identifies a user.
The @ symbol (pronounced "at") separates the user name from the location of the server
computer.
aserver.com identifies the location of the server computer.
Addresses use lowercase letters without any spaces. The name of a location contains at least a string
and, typically, a three-letter suffix, set apart by a dot (the period is pronounced "dot").
The name of a location might require several subparts to identify the server (a host name and zero or
more subdomains), each separated by dots. For example, the address aname@aserver.bserver.com
uses a subdomain.
The three-letter suffix in the location name helps identify the kind of organization operating the server.
(Some locations use a two-letter geographical suffix.) As mentioned earlier in this chapter, here are the
common suffixes and organizational affiliation:
o
o
o
o
o
o
o
o
.com (commercial)
.edu (educational)
.gov (government)
.mil (military)
.net (networking)
.org (noncommercial)
.info (informational)
.biz (business)
Mail addresses from outside the United States often use a two-letter suffix designating a country. Here
are some examples:
o
o
o
o
.jp (Japan)
.uk (United Kingdom)
.nl (the Netherlands)
.ca (Canada)
Using the Navigation toolbar in a browser
To use toolbar buttons for navigation and page control
Click one of the following buttons. Buttons on the toolbar provide quick access to commonly used
features.
Back
Click this button to display the previous page in the history list. Hold down the button to display a pop-up
menu containing the pages you can go back to in the history list. A history list contains a hierarchy of
pages you have already viewed.
You can view a subset of the history list by clicking on the Address bar’s drop-down menu.
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Forward
Click this button to display the next page in the history list. Hold down the button to display a pop-up menu
containing the history list (the pages you can go forward to). If you have retrieved a page by using the
Back button or a history menu item, using Forward displays the preceding page. Forward is only available
after you use Back or a history item.
Reload
Click this button to redisplay the current browser page, reflecting any changes made since the original
loading. To reload, your browser checks the network server to see if any change to the page has
occurred.
If there is no change, the original page is retrieved from a cache. If there is a change, the updated page is
retrieved from the network server. If you press the Reload button while holding down the Shift key (Option
key on the Mac OS), your browser retrieves the page from the network server regardless of whether the
page has been updated (the cache is not used).
Home
Click this button to display the home page designated in the browser preferences panel.
Search
Click this button to display a page containing a directory of Internet search engine sites and services.
Print
Click this button to print the content area of the currently displayed page. A dialog box lets you select
printing characteristics.
Security
Click this button to display the Security Info window. This page lets you view and interact with elements
such as encryption status, personal and site certificates, security-related applications, and passwords.
Stop
Click this button to halt any ongoing transfer of page information.
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Revisiting a page using Bookmarks
Bookmarks offer a convenient means of page retrieval. You store your bookmarks in a list. Once you add
a bookmark to your list, the item stays until you remove it or change lists. The permanence and
accessibility of bookmarks make them invaluable for personalizing your Internet access.
Browsers offer many options for creating a bookmark list. Basic options let you add and access a page
through a pop-up menu on the location toolbar or through the browser’s drop-down menu. The simplest
way to obtain direct access to a favorite page is to open the Bookmarks menu and choose Add
Bookmarks. This adds the current page as an item in the Bookmarks menu.
More advanced options, available from the Bookmarks window, let you create hierarchical menus, partial
menu displays, multiple and shared bookmark files, list descriptions, and list searches. The Bookmarks
window lists your bookmarks and offers a set of menu items to help you organize your list. In addition,
many drag-and-drop options are available for creating and filing your bookmarks.
The bookmark list you create is represented by a bookmark file on your hard disk. Each item in the list
contains the title of the page (which you can choose in a menu), the associated URL (which lets your
browser retrieve the page), and some additional date information.
The same Bookmarks menu is displayed by either the pop-up menu in the location toolbar or the
browser’s drop-down menu.
To display the Bookmarks menu
To display the Bookmarks menu using a pop-up menu, position the mouse cursor over the Bookmarks
button in the location toolbar, and press the mouse button. To display the Bookmarks menu using the
main menu bar, click on the Bookmarks drop-down menu. The Bookmarks item displays a submenu.
Add Bookmark
Adds the title of the currently displayed page as the last item in the bookmark list. The Bookmarks menu
grows as you add bookmarks.
File Bookmark
The pull-right File Bookmark menu item lets you add the current browser page to a selected bookmark
folder. The items in this menu are bookmark folders.
To edit or delete bookmarks using the Bookmarks menu
Choose Edit Bookmarks to open the Bookmarks window. You can drag and drop bookmark icons or use
the window's menu items to arrange the display of your bookmarks and bookmark folders.
To delete a bookmark, select the bookmark icon in the Bookmarks window, then press the Delete key (or
choose Delete from the Edit menu).
To display bookmarks using the Bookmarks menu
Choose one of the following items shown on the next page:
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Bookmark items
These items are the bookmarks you have created. Choose an item to display the bookmarked page.
Each time you add a bookmark, the page's title is added to this menu and links to the bookmarked page.
Navigating to pages
The Go menu allows you to navigate among pages. The menu contains the following items:
Back
Displays the previous page in the history (or frame history) list. A history list references a line of links you
have viewed; a frame history references a line of frames you have viewed within a frameset.
Forward
Displays the next page in the history (or frame history) list. If you have used Back or a history menu item
to bring back a page, Forward displays the page that's ahead in the history list. Forward is only available
after you've used Back or a history item.
Home
Displays the home page whose location is specified in the browser, available by opening the Edit menu
and choosing Preferences.
Sending and receiving electronic mail messages on your computer
Electronic mail (e-mail) is like regular mail in many ways. However, an e-mail message is transmitted
instantly across the Internet, and it costs nothing to send the message. With many e-mail programs, you
can attach files (computer programs, pictures, word processing files, etc.) to go along with the e-mail
message. Also, you can forward or send the same e-mail message to more than one person at a time,
through the use of a mailing list.
Anyone who can access the Internet can get e-mail, and sending a message to Australia is just as easy
as sending mail to someone next door. Most e-mail packages are as easy to use as standard word
processing packages, and even include features such as spell checking.
Commonly-used email client applications include Microsoft Outlook and Mozilla Thunderbird. Typical
web-based email services include Google Mail (Gmail), Yahoo Mail, and AOL Mail.
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Create new messages
To create a new mail message, start up the e-mail program ... we'll use Microsoft Outlook as an example.
There are several main groups on the program interface: the Inbox, the Sent Mail folder, the Drafts folder,
and so on. There is a button at the top of the screen that lets you create a new email message. Click on
this button to begin creating a mail message.
You will need to address the message, but for now we'll skip that part. Simply begin typing in your
message in the space provided. Email programs work just like a word processor, so just go ahead and
type your message.
Addressing messages
Once you have written your message, you will need to specify the e-mail address of the person (or
persons) to which you wish to send the message. Just as with the regular mail system, providing an
incorrect address will ensure that the letter does NOT get through. Getting the correct address is key to
making sure the message goes through. A correct e-mail address will look something like this:
LLOYDWA@pgcc.edu
william.allen.lloyd@census.gov
researchtech@juno.com
The first part of the e-mail address (the part before the "@" sign) indicates the name (or account name) of
the person who has an account on that e-mail service. The last part indicates the organization that is
providing the person with an e-mail account. Make sure that you know the exact e-mail name when
addressing your message.
You can send the same message to multiple persons at the same time. You can simply address the
message to all the individuals to which you wish to send the message, or you can create a "mailing list" to
a group of individuals that can be used over again when needed.
Attaching files to messages
In virtually all e-mail programs, you can attach any kind of file to an e-mail message, and transmit a copy
of that file with your message to the intended recipient. If your mail service supports this feature (some do
not), you would click on the "Attach" button, and then select the name of the file from wherever it is
located on your hard disk.
When you send the e-mail message, a copy of the file you selected will be sent with your message.
There is one thing to note when sending files to people over the Internet: large files may take a long time
to send through your e-mail service, and may take a long time to retrieve for the recipient. Be considerate
of this when sending files along with your mail message.
Sending and receiving messages
When you connect to your e-mail host server (that's the computer that is providing you with
e-mail service), your e-mail program will check to see if you have any new messages waiting for you
since you last logged into the server. If you do, the messages will be transmitted from the server to your
computer and stored on your hard disk. You will then be able to retrieve the mail messages and read
them.
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At the same time, the e-mail server will check to see if you have any messages on your computer that
need to be transferred to the server and sent over the Internet. Your e-mail program will handle that
automatically when you log into the server.
Reading messages
Once your e-mail service forwards your e-mail messages to your hard disk, you may read your mail
messages at your leisure. If you wish, you may print out your messages to your local printer.
Replying to and forwarding messages
If a mail message arrive that requires a response, you are able to reply back to the message's sender, or
you can forward the message on to other readers. Simply use the "Reply" option in your mail program to
send a return message; the e-mail program will automatically enter that person's e-mail address into the
address field. Type in your response, and send the message when you are done.
To forward the message to others, use the "Forward" option in your e-mail program. Specify the name of
the person (or persons) to whom you wish the message to be sent. If you wish, you may also add a note
to the message you are sending.
When you are finished, click on the "Send" button (or use the "Send" option) to mail your message.
Printing messages
Printing your mail message is as easy as selecting the "Print" option from the drop-down menu, or clicking
on the "Print" button in your e-mail program. Make sure your printer is turned on before trying to print your
messages.
Deleting, saving and storing messages
As time goes by, your inbox of mail messages may become rather large. You probably will not want to
keep EVERY message you received, so you may want to review your mail messages about once a week.
Upon this review, you will likely decide to delete some messages, and permanently store others to your
hard disk.
To delete a mail message, simply click once on the desired message on the message list, and then press
the Delete key. You can also select multiple messages for deletion by holding down the Shift key and
clicking on the desired files, and then pressing the Delete key.
To save a mail message as a file on your hard disk, open the mail message by double-clicking on it, then
click on File, then click on Save from the drop-down menu. Once you have saved the message to a file on
your hard disk, you can then delete the message from your inbox.
Finding messages and addresses
Most e-mail programs will let you search for a message by the name of the sender, by the subject of the
message, or by searching for specific text within the message.
Simply access the search feature within the e-mail program, then input the desired name or words for
which you wish to search, and press Enter ... the search engine will momentarily give you the results of
the search.
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Spam, and how to deal with it
Spam in the nickname for unsolicited e-mail, just like the junk mail that comes to you via the US Postal
Service. If you receive spam, respond back to the individual or company and let them know that you no
longer wish to receive their unsolicited e-mail. If you are receiving messages after attempting to be
dropped from the spammer’s list of “customers”, you can use spam blockers, or you can simply just
delete the messages. Unopened spam email messages typically pose no security risk to your PC.
There are also a number of anti-spam applications available via the Internet that can help you if you
receive an inordinate amount of spam e-mail.
Your e-mail client software (Outlook, Thunderbird, or your webmail providers) should have features built
into it that will allow you to block spam emails from coming into your Inbox.
What is an ISP?
An ISP is an Internet Service Provider. ISPs provide users with a gateway by which they can access the
Internet to use the world-wide web, transfer files via the File Transfer Protocol (FTP), or to send email.
ISPs provide to their clients a software package (or they use the dial-up software within Windows) that
creates either a Serial Link to the Internet Protocol (SLIP) connection or a Point-to-Point over Ethernet
Protocol (PPPoE) connection between the home (or office) computer and the ISP.
TCP/IP is the data transfer protocol used over SLIP or PPPoE connections, because TCP/IP is the sole
protocol used to transfer data over the Internet.
There are thousands of ISPs worldwide; some are large corporations, such as Verizon and Comcast, and
some are smaller, local service providers. ISPs charge a monthly (or hourly) fee to connect your
computer to the ISP and the Internet.
If you are having problems connecting to the Internet, your first contact should be to your Internet service
provider. A portion of the monthly fee you pay goes towards providing staff to assist you when you are
having problems getting connected.
If the service provider is not providing adequate service and resolving your problems, insist upon
speaking with a Tier 2 service professional. If they cannot give you adequate service, you should
consider selecting another provider that CAN provide you with support.
NOTES
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Chapter 15. iOS and Android Operating Systems, Smartphones,Tablets, and Other Mobile Devices
This portion of the text covers the newest portion of the A+ Certification examinations. Starting with the
220-801 and 220-802 exams, smartphones, tablets, phablets (phone + tablet) and the operating
systems they use will be included in the exam. iOS, the Apple operating system and Android, the other
major tablet/smartphone operating system, also will be covered in the newest examinations.
Apple devices like the iPhone and iPad use the iOS mobile operating system. Devices like the Samsung
Galaxy Tab, the Kindle Fire, the Barnes and Noble Nook, and many smartphones use the Android
operating system. These operating systems tend to be updated somewhat frequently. This textbook will
discuss the features of Apple iOS version 9 and Android version 5, code-named “Lollipop.”
The devices that run these operating systems may have subtle differences in hardware configuration, but
the operating systems will function the same way regardless of hardware and features.
Both of these mobile operating systems have a common set of features, which include the following
shown below:






















Hardware that supports WiFi, 3G and/or 4G Internet connectivity
Ports to add SD-style memory cards and USB or Thunderbolt devices
Browser(s) for Internet access
Literally hundreds of thousands of available apps for almost any need
Email client software
Messaging and chat software, and applications for access to FaceBook and other social media
Music and video playback apps, such as iTunes and Google Play
Book readers, such as the Amazon Kindle reader and the Nook reader
Access to cloud-based data storage, such as iCloud and Google Cloud
Bluetooth connectivity to speakers, microphones, printers, and keyboards
One or more cameras, to take pictures and/or have video-based chats over the Internet
Photo-editing and video-editing apps
Map and GPS-based directional apps, like Google Maps and Apple Maps
Stores, like the App Store or the Google Play store, to purchase and download new apps to the
device
Near-field communication (NFC) technology to support apps like ApplePay or GooglePay
Games, both built-in and downloadable
Calculators, contact lists, clocks, and alarm timers
Voice-recognizing apps that search for information, such as Apple Siri and Google Search
Infrared (IR) or Bluetooth data sharing between devices
Security features to lock the phone or tablet
Synchronization ability to store phone or tablet data onto a desktop PC, laptop or Mac
Standard mobile telephone features (for iPhones and Android phones)
A common problem with tablets and smartphones is that typically they are NOT upgradeable, not by the
customer, and not by the average PC technician. If the glass screen is damaged, there are firms that will
provide customers with a replacement touchscreen component (digitizer) or glass screen. However, the
process involved in replacing the damaged components usually voids any warranty from the
manufacturer. The same thing is true when it comes to replacing a defective battery.
Many Android tablets will allow the user to add a microSD card to the unit, thereby increasing the data
storage capacity. Typically, there is no way to increase the RAM or storage capacity in a tablet device or
smartphone. This being the case, most tablets and smartphones can only be repaired by
factory-authorized service technicians, and only in their authorized facilities.
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Typically, if a tablet or smartphone becomes damaged, the least expensive option is to replace the unit
altogether. Depending on the amount of damage and whether the user has backed up their data to a PC
or a cloud-based storage solution, the customer may lose a significant amount of information, pictures,
videos, or applications. If the customer insists upon repairing their damaged tablet or smartphone, refer
them to an authorized repair facility for that device’s manufacturer. Typical problems include cracked or
non-responsive touchscreens, extremely short battery life, no sound from speakers, loss of wireless or
Bluetooth connectivity, overheating, and inability to power on the system.
Connecting to networks and email services on a smartphone or tablet
Smartphones and tablets allow users to connect to 3G and/or 4G cellular phone services, as well as
available WiFi hotspots. The cellular service provider will configure the smartphone or tablet so that it will
access any 3G or 4G connectivity resources. Devices that have only WiFi capabilities may need to be
configured by the customer, or by you the technician.
Virtually all tablets and smartphones have Bluetooth capabilities built into them. To enable your
Bluetooth-capable tablet or smartphone to recognize your headset, earpiece, printer or speakers, you will
need to perform the following steps:







Enable (turn on) the Bluetooth transceiver on your tablet or smartphone
Make sure the Bluetooth-capable device is within 10 feet of your tablet or smartphone, and that
the device is charged up or connected to power
Turn on your Bluetooth-capable device (earpiece, printer, etc.)
Open the Bluetooth control application on your tablet or smartphone, and set it to Discovery mode
Within about two minutes, your tablet should identify and or automatically configure your tablet or
smartphone to recognize and use your Bluetooth device
In some cases, you may need to enter a PIN (personal identification number) code to complete
the device configuration process
Test your newly-connected device to ensure it is working properly
If you have problems getting your Bluetooth-capable device to be recognized, refer to the documentation
for that device, or search the Internet for instructions and troubleshooting tips. You also can contact the
device’s manufacturer for assistance.
To send and receive e-mail messages on your tablet or smartphone, perform the steps shown below:






Open your e-mail client application, and then open the Options (or Configuration) dialog box
Enter the POP3 (incoming mail) and SMTP (outgoing mail) server addresses, along with your
e-mail address and/or your e-mail password
If your email provider is using Secure Sockets Layer (SSL), enter the proper SSL port number and
any other required information
If your e-mail provider is using IMAP (the Internet Message Access Protocol), enter the necessary
account information, such as username/email address, password, and so forth
Attempt to access the e-mail account; open an existing or new email message, and send a test
message to verify the configuration settings are correct
Depending upon your email provider, a dedicated app will be available that will simplify this
whole process
If you have problems getting your e-mail service configured, contact your e-mail service provider for
assistance, or search the Internet for instructions and troubleshooting tips. You also can contact the
device’s manufacturer for assistance.
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Device security and antivirus protection
Your tablet or smartphone, by default, has security features enabled to prevent unauthorized access and
use of the device. For example, your device should prompt you for a four-digit number (or some other
method) that you will use to unlock the screen on your tablet or smartphone. This feature will be setup
when you initially configure the device; you can change these settings at any time as well.
With devices like the BlackBerry and the iPhone, if you have a government-owned or corporately-owned
phone or tablet, your network administrator likely has enabled the remote wiping feature. This enables
the administrator to permanently erase any confidential or proprietary information from the device in the
event it is lost or stolen. In addition, the GPS features in these devices allow the network administrator to
locate the device in the event of loss or theft. This aids in retrieving the device, and catching the person
who may have stolen it.
If the user attempts to log into the device with the incorrect passcode, after a certain number of failed
attempts the device will be locked. The lockout period can be varied from 15 minutes, to some longer
period of time, or until a secret security code is input to unlock the device. The user and/or the network
administrator can set the timeout and lockout values for the device.
Further, your network administrator can remotely backup any applications or data that may be stored on
the smartphone or tablet. In the event that the device is damaged and beyond repair, a backup resides on
the company’s server, so that little or no data is lost.
As with any other computing device, there is a possibility that a virus or piece of malicious code could
attack the operating system and corrupt the tablet or smartphone. Fortunately, the Apple iOS and the
Android operating systems are built largely upon the Linux operating system. Linux is highly impervious
to viruses and malicious software, so your device and its data are relatively safe.
There are antivirus products available for tablets and smartphones that can further enhance the safety
and security of your device and the data upon it. AVG does make an antivirus product for the Android OS,
and there are many other similar products available on the Google Play store. The same is true for
iOS-capable devices; the App Store has a number of reputable antivirus products available for download
and installation.
Finally, like any other operating system, there will be periodic updates and patches to operating systems
currently in public use. These can be downloaded and installed manually, or automatically when the
update is posted to the user community. For example: on an Android device, from the menu, select
Settings, then select About phone/device, and then press System Updates.
A message will appear if there are no updates. If updates are available, click Install Now to load them to
your device. The device will reboot several times during the update process; do NOT turn off the device
during this process. In fact, the device should be connected to the charger when performing a system
update, to ensure that the operating system is not corrupted accidentally.
Differences between Apple iOS and the Android operating systems
Both Android and iOS look and operate in very similar ways. One can launch a program (called an app)
by touching on the app’s icon on the screen. Navigating the operating system is done by “swiping” across
the screen to find an app, “pinching” to make the image smaller or “unpinching” to make the image larger,
and so forth.
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However, the Android operating system is open-source, which means that anyone can obtain the source
code that drives the inner workings of the system. Apple iOS is a closed-source operating system, as is
the Windows Mobile operating system. Android users can modify the operating system any way theu
wish (provided they know how to manipulate the program code) or develop apps that work seamlessly
with the operating system. Apple iOS does not distribute the source code for their operating system; only
the Apple corporation can upgrade or modify the system.
Major corporations and large government agencies have been moving towards open-source operating
systems and applications, specifically because they can modify (and freely distribute) the code within the
OS or the applications. Having to depend upon a company’s next OS or application revision can slow
down production systems, and the upgraded product still may not have all of the features needed by the
customer.
Both operating systems support hundreds of thousands of apps, either in the Apple iTunes App Store or
the Google Play store. However, apps written for iOS generally are not compatible with the Android OS.
As such, separate versions of a given app must be created to run on either of these operating systems.
e-Readers
The Amazon Kindle and Barnes and Noble Nook are examples of e-reader devices. While much like a
tablet, these devices primarily enable users to read books designed to be read in electronic format. The
companies that sell these devices make thousands of book titles available to customers, and they also
provide apps that will enable tablet devices to work just like an e-reader. Kindle and Nook e-readers do
have wireless connectivity and an Internet browser, but their browsing capabilities can be somewhat
limited.
GPS and geotracking features
Smartphones and tablets typically have the ability to use GPS satellite navigation information, just like a
Garmin, Magellan or TomTom GPS device used in your car. This allows the user to obtain point-to-point
directions to any given location. It also allows the user to both make available their location for others to
see, and also to get information about businesses and services in their immediate vicinity.
Many businesses “advertise” their presence on WiFi and 3G/4G cellular networks, so that a customer
can find their location and obtain information about the products and services they provide. One even
can obtain customer reviews about the quality of services of these businesses in the immediate area.
Such units typically will need to have updated maps downloaded to them, in order to provide the most
accurate information possible. Such updates are completed by downloading the new maps to a
computer, and then transferring the map to the GPS device by a USB connection to the PC.
Both the Apple iOS and Android operating systems support these GPS features, and many apps are
available that allow users to leverage this data.
With the advent of smartphones that have GPS capabilities built into them, automobile GPS navigation
devices are becoming less common. Many new cars have GPS units built into the “infotainment
system” in the vehicle as well, relieving the need for a separate GPS device.
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IMEI and IMSI numbers
On smartphones, there are two numbers that dictate how the phone will communicate and operate on a
cellular network. The International Mobile Subscriber Identity (IMSI) dictates what network that device
will work with, such as Verizon or AT&T. The International Mobile Equipment Identity (IMEI) number is
like the MAC address on a network card; it uniquely identifies each cellular phone or device. No two
cellular devices can have the same IMEI number..
Miscellaneous portable device accessories
With all of the devices mentioned in this chapter, there are a number of accessories that will protect the
device, extend the battery length, allow the device to dock to a keyboard (and perhaps also a monitor),
add a credit card reader and application to accept payments, and so forth. Protective covers keep tablet
and phones screens from being damaged, cases will protect them from impact shocks, and game pads
will enable easier game playing.
On the A+ examination, you will be expected to know about devices such as these.
Mobile hotspots
Many of the major wireless telecommunication companies (Verizon, Sprint, AT&T, T-Mobile, Cricket,
Boost, and others) provide mobile wireless “hot-spots” that allow the customer to connect to the Internet
through the use of a cellular 3G, 4G or 4GLTE signal. These provide an alternative to using a public wifi hotspot, which could be prone to hacking by unscrupulous individuals. They also provide Internet
access in more remote locations, so long as a cellular signal is present. Technical support for these
devices normally is provided by the cellular carriers that make them available.
Mobile payment services
Recently applications like ApplePay and GooglePay will enable a tablet or smartphone to make point-of
sale payments to vendors from a customer’s bank account, PayPal, or other payment services. Nearfield communications (NFC) technology built into the phones, along with some form of biometric
fingerprint reader, ensure that payments made are done securely.
Screen orientation and screen calibration
Tablet devices and smartphones can display information in either portrait mode (longer than wider) or
landscape mode (wider than longer). The device contains an accelerometer and/or a gyroscope that
senses whether the tablet or phone is being held in portrait or landscape mode, and adjusts the display
automatically. This accelerometer also can be used to enable game playing to sense the motions of the
person holding the device.
In order for the operating system to properly launch any application, the screen needs to be calibrated, so
that the touch input on the screen is recognized correctly. For example: in the Android OS, one can
recalibrate the touchscreen by going to Menu, Settings, Language and keyboard, Touch Input, Text
Input, under Finger touch precision, and choose the Calibration Tool. The user also can select the Reset
calibration option to return to the default settings. Devices using iOS will use a similar process to
recalibrate the touch screen.
If the user still has a problem with the screen not being calibrated properly, the screen may have become
defective. The user should check with their cellular service provider or store where the device was
purchased and determine if the device is still covered under warranty.
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SDKs and APK files
An SDK is a software development kit, that allows a programmer to develop an application (or app) for
a mobile device. The resulting application is compiled into an .APK file, which stands for Android
Application package. APK files can be downloaded from an app store, and then installed onto the
device. Apps developed for iOS devices have an .IPA extension, and perform the same function.
Synchronizing data from a smartphone or tablet to a PC or Mac
Typically a smartphone or tablet will allow the user to synchronize data onto a laptop, desktop PC or a
Mac, and also to cloud services like Apple iCloud or Google Cloud. The data will be transferred from
the device to the computer by USB, Firewire, or some proprietary cable connection. In some cases,
special software may need to be installed to the computer to enable the data synchronization process
(such as iTunes for music and video files).
This software should come with the device when purchased. If the installation CD or DVD is missing, the
manufacturer’s website should have that software available for download.
Types of data that can be synchronized include:






Telephone, email and address contact lists
Application programs and the data files created by these apps
Email messages
Pictures
Music files (in iTunes, .MP3 or some other format)
Video files (in a variety of formats)
It is important to remember that once data is synchronized between a smartphone/tablet and a computer,
ANY change to that data made on one device will be transferred to the other at the next synchronization
session. If conflicting changes are made to the same data record (for example, the person’s mailing
address was changed two different ways, one way on the tablet, and another on the PC), the
synchronizing application may have difficulties when attempting to create one single data record. This
can cause duplicate records to appear in BOTH the computer and the smartphone/tablet, some of which
will contain incorrect or old data.
If records need to be added or changed, try to be consistent in the method you use to make these
changes. Either make the additions or changes on the smartphone/tablet, or on the computer, but not
both. This will reduce the likelihood of duplicate and/or inaccurate records.
Wearable Devices
There now is a class of web-enabled, tablet-accessible devices called “wearables.” Devices like the
Apple Watch will synchronize with a user’s iPhone. FitBit devices will monitor aspects of your physical
health (heart rate, blood pressure, number of steps walked per day) and relay this information to an
application on your tablet or PC. Headset devices like the Oculus Rift will allow you to interact with
tablets and gaming devices and provide an immersive, 3D-like virtual experience. In your work to
support the IT needs of customers, you will need to understand what these devices are, how they
connect to other kinds of computing devices, and how to trouble-shoot problems with them.
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WiFi calling
Since tablets and smartphones can access wireless networks, a number of applications have been
developed to allow these devices to make calls over the Internet. MagicJack, Skype, and Vonage are
some examples of applications that allow for Wi-fi calls.
If you want further information about tablet devices, smartphones or iPhones, or any of the other devices
mentioned in this chapter, click the following links shown below:
Apple website: http://www.apple.com
Samsung website: https://www.samsung.com/us/
HTC website: http://www.htc.com/us/
LG website: http://www.lg.com/us
Nokia website: http://www.nokia.com/us-en/
BlackBerry website: http://us.blackberry.com/
FitBit website: http://www.fitbit.com/
Garmin website: http://www.garmin.com/en-US
Amazon website: http://www.amazon.com/
Barnes and Noble website: http://www.barnesandnoble.com/
NOTES
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Chapter 16. Glossary of Terms
This portion of the text provides the definitions for hundreds of different terms related to personal
computing, computer hardware, software, and applications.
The author recommends to the reader that if there are terms missing from the glossary that should be
included, please let him know, and they will be included in the next edition of the text.
The glossary begins on the next page.
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80286
An Intel microprocessor with 16-bit registers, a 16-bit data bus, and a 24-bit address bus. Can operate in
real and protected virtual modes.
80287
An Intel math coprocessor designed to perform floating-point math with much greater speed and
precision than the main CPU. The 80287 can be installed in most 286- and some 386DX-based systems,
and adds more than 50 new instructions to what is available in the primary CPU alone.
80386DX
An Intel microprocessor with 32-bit registers, a 32-bit data bus, and a 32-bit address bus. This processor
can operate in real, protected virtual, and virtual real modes.
80386SX
An Intel microprocessor with 32-bit registers, a 16-bit data bus, and a 24-bit address bus. This processor,
designed as a low-cost version of the 386DX, can operate in real, protected virtual, and virtual real
modes.
80387DX
An Intel math coprocessor designed to perform floating-point math with much greater speed and
precision than the main CPU. The 80387DX can be installed in most 386DX-based systems, and adds
more than 50 new instructions to what is available in the primary CPU alone.
80387SX
An Intel math coprocessor designed to perform floating-point math with much greater speed and
precision than the main CPU. The 80387SX can be installed in most 386SX-based systems, and adds
more than 50 new instructions to what is available in the primary CPU alone.
80486DX
An Intel microprocessor with 32-bit registers, a 32-bit data bus, and a 32-bit address bus. The 486DX has
a built-in cache controller with 8K of cache memory as well as a built-in math co-processor equivalent to
a 387DX. The 486DX can operate in real, protected virtual, and virtual real modes.
80486DX2
A version of the 486DX with an internal clock doubling circuit that causes the chip to run at twice the
motherboard clock speed. If the motherboard clock is 33MHz, then the DX2 chip will run at 66MHz. The
DX2 designation applies to chips sold through the OEM market, while a retail version of the DX2 is sold
as an Overdrive processor.
80486SX
An Intel microprocessor with 32-bit registers, a 32-bit data bus, and a 32-bit address bus. The 486SX is
the same as the 486DX except that it lacks the built-in math coprocessor function, and was designed as a
low-cost version of the 486DX. The 486SX can operate in real, protected virtual, and virtual real modes.
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80487SX
An Intel microprocessor with 32-bit registers, a 32-bit data bus, and a 32-bit address bus. The 487SX has
a built-in cache controller with 8K of cache memory as well as a built-in math coprocessor equivalent to a
387DX. The 486DX can operate in real, protected virtual, and virtual real modes. This processor is a
complete processor and math coprocessor unit, not just a math coprocessor. The 487SX is designed to
upgrade systems with the 486SX processor, which lacks the math coprocessor function. When a 487SX
is installed in a system, it shuts down the 486SX and takes over the system. In effect, the 487SX is a
full-blown 486DX modified to be installed as an upgrade for 486SX systems.
8086
An Intel microprocessor with 16-bit registers, a 16-bit data bus, and a 20-bit address bus. This processor
can operate only in real mode.
8087
An Intel math coprocessor designed to perform floating-point math with much greater speed and
precision than the main CPU. The 8087 can be installed in most 8086- and 8088-based systems, and
adds more than 50 new instructions to what is available in the primary CPU alone.
8088
An Intel microprocessor with 16-bit registers, an 8-bit data bus, and a 20-bit address bus. This processor
can operate only in real mode, and was designed as a low-cost version of the 8086.
8514/A
An analog video display adapter from IBM for the PS/2 line of personal computers. Compared to previous
display adapters such as EGA and VGA, it provides a high resolution of 1024x768 pixels with as many as
256 colors or 64 shades of gray. It provides a video coprocessor that performs two-dimensional graphics
functions internally, thus relieving the CPU of graphics tasks. It is an interlaced monitor: It scans every
other line every time the screen is refreshed.
Abend
Short for abnormal end. Used when the execution of a program or task is terminated unexpectedly
because of a bug or crash.
AC
Alternating current. The frequency is measured in cycles per seconds (cps), or hertz. The standard value
running through the wall outlet is 120 volts at 60 Hertz, through a fuse or circuit breaker that usually can
handle about 20 amps.
Accelerator board
An add-in board replacing the computer's CPU with circuitry that enables the system to run faster.
ACL
Stands for Access Control List, which is used to control permissions on networked resources.
AP
Stands for Access Point, typically referring to wireless networks.
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Access time
The time that elapses from the instant information is requested to the point that delivery is completed.
Usually described in nanoseconds for memory chips. The IBM PC requires memory chips with an access
time of 200 nanoseconds, and the AT requires 150-nanosecond chips. For hard disk drives, access time
is described in milliseconds. Most manufacturers rate average access time on a hard disk as the time
required for a seek across one-third of the total number of cylinders plus one-half of the time for a single
revolution of the disk platters (latency).
Accumulator
A register (temporary storage) in which the result of an operation is formed.
ACPI
Stands for Advanced Configuration Power Interface, which controls power-saving features on PCs and
laptops; this feature is configurable within the OS and within the BIOS.
Acronym
An acronym is a word or group of letters formed from the first or first few letters of a series of words. For
example, CPU is an acronym for Central Processing Unit. This glossary contains definitions for many
acronyms popular in the personal computer industry.
ACT
Short for the term Activity.
Active high
Designates a digital signal that has to go to a high value to produce an effect. Synonymous with positive
true.
Active low
Designates a digital signal that has to go to a low value to produce an effect. Synonymous with negative
true.
Actuator
The device that moves a disk drive's read/write heads across the platter surfaces. Also known as an
access mechanism.
Adapter
The device that serves as an interface between the system unit and the devices attached to it. Used by
IBM to be synonymous with circuit board, circuit card, or card.
Address
Refers to where a particular piece of data or other information is found in the computer. Also can refer to
the location of a set of instructions.
Address bus
One or more electrical conductors used to carry the binary-coded address from the microprocessor
throughout the rest of the system.
ADSL
Stands for Asymmetrical Digital Subscriber Line; also known as simply DSL; a method of providing
Internet access through traditional telephone lines.
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AGP
Stands for Accelerated Graphics Port, a type of video card and motherboard bus interface.
AHCI
Stands for Advanced Host Controller Interface, used to allow input/output between disk devices and/or
USB data storage devices.
Alphanumeric characters
A character set that contains only letters (A-Z) and digits (0-9). Other characters, such as punctuation
marks, also may be allowed.
Ampere
The basic unit for measuring electrical current. Also called amp.
Analog loopback
A modem self-test in which data from the keyboard is sent to the modem's transmitter, modulated into
analog form, looped back to the receiver, demodulated into digital form, and returned to the screen for
verification.
Analog signals
Continuously variable signals in which the slightest change may be significant. Analog circuits are more
subject to distortion and noise but are capable of handling complex signals with relatively simple circuitry.
An alternative to analog is digital, in which signals are in only one of two states.
AND
A logic operator having the property that if P is a statement, Q is a statement, R is a statement,..., then the
AND of P,Q,R,... is true if all statements are true and is false if any statement is false.
AND gate
A logic gate in which the output is 1 only if all inputs are 1.
ANSI
Acronym for American National Standards Institute, a non-governmental organization founded in 1918 to
propose, modify, approve, and publish data processing standards for voluntary use in the United States.
Also the U.S. representative to the International Standards Organization (ISO) in Paris and the
International Electrotechnical Commission (IEC).
Answer mode
A state in which the modem transmits at the predefined high frequency of the communications channel
and receives at the low frequency. The transmit/receive frequencies are the reverse of the calling
modem, which is in originate mode.
Anti-glare filter
A piece of semi-transparent plastic that attaches to a monitor to reduce glare from ambient light.
APA
All points addressable. A mode in which all points of a displayable image can be controlled by the user or
a program.
API
An acronym for application program interface. A system call (routine) that gives programmers access to
the services provided by the operating system. In IBM-class systems, the ROM BIOS and DOS together
present an API that programmers can use to control system hardware.
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APIPA
Short for Automatic Private IP Addressing, a feature of later Windows operating systems. With APIPA,
DHCP clients can automatically self-configure an IP address and subnet mask when a DHCP server isn't
available. When a DHCP client boots up, it first looks for a DHCP server in order to obtain an IP address
and subnet mask. If the client is unable to find the information, it uses APIPA to automatically configure
itself with an IP address from a range that has been reserved especially for Microsoft.
The IP address range is 169.254.0.1 through 169.254.255.254. The client also configures itself with a
default class B subnet mask of 255.255.0.0. A client uses the self-configured IP address until a DHCP
server becomes available.
The APIPA service also checks regularly for the presence of a DHCP server (every five minutes,
according to Microsoft). If it detects a DHCP server on the network, APIPA stops, and the DHCP server
replaces the APIPA networking addresses with dynamically assigned addresses.
APIPA is meant for nonrouted small business environments, usually less than 25 clients.
APM
Stands for Advanced Power Management.
Arbitration
A method by which multiple devices attached to a single bus can bid or arbitrate to get control of that bus.
Archive bit
The bit in a file's attribute byte that sets the archive attribute. Tells whether the file has been changed
since it last was backed up.
Archive medium
A storage medium (floppy disk, tape cartridge, or removable cartridge) to hold files that need not be
accessible instantly.
ARCnet
An acronym for Attached Resource Computer Network, a baseband, token-passing local area network
technology offering a flexible bus/star topology for connecting personal computers. Operates at 2.5
megabits per second, is one of the oldest LAN systems, and has become popular in low-cost networks.
Originally developed by John Murphy, of Datapoint Corporation, although ARCnet interface cards are
available from a variety of vendors. ARCNet is now obsolete.
Areal Density
Areal Density is a calculation of the Bit Density (Bits Per Inch, or BPI) multiplied by the Track Density
(Tracks Per Inch, or TPI), which results in a figure indicating how many bits per square inch are present
on the disk surface.
ARP
Stands for Address Resolution Protocol, a part of the TCP/IP protocol suite. Allows the user to map an IP
address to a computer recognized on a network.
ARQ
Automatic repeat request. A general term for error-control protocols that feature error detection and
automatic retransmission of defective blocks of data.
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ASCII
An acronym for American Standard Code for Information Interchange, a standard seven-bit code created
in 1965 by Robert W. Bemer to achieve compatibility among various types of data processing equipment.
The standard ASCII character set consists of 128 decimal numbers, ranging from 0 through 127,
assigned to letters, numbers, punctuation marks, and the most common special characters. In 1981 IBM
introduced the extended ASCII character set with the IBM PC, extending the code to eight bits and adding
characters from 128 through 255 to represent additional special mathematical, graphics, and foreign
characters.
ASCII character
A 1-byte character from the ASCII character set, including alphabetic and numeric characters,
punctuation symbols, and various graphics characters.
ASR
Stands for Automated System Recovery.
ASME
An acronym for the American Society of Mechanical Engineers.
Assemble
To translate a program expressed in an assembler language into a computer machine language.
Assembler language
A computer-oriented language whose instructions are usually in one-to-one correspondence with
machine language instructions.
Asymmetrical modulation
A duplex transmission technique that splits the communications channel into one high-speed channel
and one slower channel. During a call under asymmetrical modulation, the modem with the greatest
amount of data to transmit is allocated the high-speed channel. The modem with less data is allocated the
slow, or back, channel (450 bps). The modems dynamically reverse the channels during a call if the
volume of data transfer changes.
Asynchronous communication
Data transmission in which the length of time between transmitted characters may vary. Timing is
dependent on the actual time for the transfer to take place, as opposed to synchronous communication,
which is timed rigidly by an external clock signal. Because the receiving modem must be signaled about
when the data bits of a character begin and end, start and stop bits are added to each character.
ATA
An acronym for AT Attachment interface, an IDE disk interface standard introduced in March 1989 that
defines a compatible register set and a 40-pin connector and its associated signals.
ATAPI
Stands for Advanced Technology Attachment Packet Interface; synonym for IDE/EIDE drives.
ATM
Stands for Asynchronous Transfer Mode, a means of data transfer on networks.
ATX
Stands for Advanced Technology eXtended, a style/size of computer cases and motherboards.
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Attribute byte
A byte of information, held in the directory entry of any file, that describes various attributes of the file,
such as whether it is read-only or has been backed up since it last was changed. Attributes can be set by
the DOS ATTRIB command.
Audio
A signal that can be heard, such as through the speaker of the PC. Many PC diagnostics tests use both
visual (on-screen) codes and audio signals.
Audio frequencies
Frequencies that can be heard by the human ear (approximately 20 to 20,000 hertz).
AUP
Stands for Acceptable Use Policy, an agreement between clients and managers concerning the proper
use of networked technology.
Auto answer
A feature in modems enabling them to answer incoming calls over the phone lines without the use of a
telephone receiver.
Auto dial
A feature in modems enabling them to dial phone numbers without the use of a telephone transmitter.
AUTOEXEC.BAT
A special batch file that DOS executes at start-up. Contains any number of DOS commands that are
executed automatically.
Automatic head parking
Disk drive head parking performed whenever the drive is powered off. Found in all hard disk drives with a
voice-coil actuator.
A/V
Stands for Audio/Visual.
Average Access Time
The average time it takes a disk drive to begin reading any data placed anywhere on the drive. This
includes the Average Seek time, which is when the heads are moved, as well as the Average Latency,
which is the average amount of time required for any given data sector to pass underneath the heads.
Together these make up the Average Access Time.
Average Latency
The average time required for any byte of data stored on a disk to rotate under the disk drive's read/write
head. Equal to one-half the time required for a single rotation of a platter.
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Average Seek Time
Average seek time for a drive is the average amount of time it takes to move the heads from one random
cylinder location to another, usually including any head settling time. In many cases, the average seek is
tested across one third of the total number of cylinders for consistency in measurement.
AVI
AVI is an acronym for Audio Video Interleave, a storage technique developed by Microsoft for their "Video
for Windows" product that combines audio and video into a single frame or track, saving valuable disk
space and keeping audio in synchronization with the corresponding video.
Backup
The process of duplicating a file or library onto a separate piece of media. Good insurance against loss of
an original.
Backup disk
Contains information copied from another disk. Used to make sure that original information is not
destroyed or altered.
Bad sector
A disk sector that cannot hold data reliably because of a media flaw or damaged format markings.
Bad track table
A label affixed to the casing of a hard disk drive that tells which tracks are flawed and cannot hold data.
The listing is entered into the low-level formatting program.
Balanced signal
A term referring to signals consisting of equal currents moving in opposite directions. When balanced or
nearly balanced signals pass through twisted pair lines, the electromagnetic interference effects such as
crosstalk caused by the two opposite currents largely cancel each other out. Differential signaling is a
method that uses balanced signals.
Balun
Short for balanced/unbalanced. A type of transformer that enables balanced cables to be joined with
unbalanced cables. For example, a twisted pair (balanced) cable can be joined with a coaxial cable
(unbalanced) if the proper balun transformer is used.
Bandwidth
Generally the measure of the range of frequencies within a radiation band required to transmit a particular
signal. Measures in millions of cycles per second the difference between the lowest and highest signal
frequencies. The bandwidth of a computer monitor is a measure of the rate that a monitor can handle
information from the display adapter. The wider the bandwidth, the more information the monitor can
carry, and the greater the resolution.
Bank
The collection of memory chips that make up a block of memory readable by the processor in a single bus
cycle. This block therefore must be as large as the data bus of the particular microprocessor. In IBM
systems, the processor data bus is usually 8, 16, or 32 bits, plus a parity bit for each 8 bits, resulting in a
total of 9, 18, or 36 bits for each bank.
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Bar code
The code used on consumer products and inventory parts for identification purposes. Consists of bars of
varying thicknesses to represent characters and numerals that are read with an optical reader. The most
common version is called the Universal Product Code (UPC).
Baseband
The transmission of digital signals over a limited distance. ARCnet and EtherNet local area networks
utilize baseband signaling. Contrasts with broadband transmission, which refers to the transmission of
analog signals over a greater distance.
BASIC
An acronym for Beginner's All-purpose Symbolic Instruction Code, a popular computer programming
language. Originally developed by John Kemeny and Thomas Kurtz, in the mid-1960s at Dartmouth
College. Normally an interpretive language, meaning that each statement is translated and executed as it
is encountered; but can be a compiled language, in which all the program statements are compiled before
execution.
Batch file
A set of commands stored in a disk file for execution by the operating system. A special batch file called
AUTOEXEC.BAT is executed by IBM DOS each time the system is started. All DOS batch files have a
.BAT file extension.
Baud
A unit of signaling speed denoting the number of discrete signal elements that can be transmitted per
second. The word baud is derived from the name of J.M.E. Baudot (1845-1903), a French pioneer in the
field of printing telegraphy and the inventor of Baudot code. Although technically inaccurate, baud rate
commonly is used to mean bit rate. Because each signal element or baud may translate into many
individual bits, bits per second (bps) normally differs from baud rate. A rate of 2400 baud means that 2400
frequency or signal changes per second are being sent, but each frequency change may signal several
bits of information. Most people are surprised to learn that 2400 and 1200 bps modems transmit at 600
baud, and that 9600 and 14400 bps modems transmit at 2400 baud.
Baudot code
A 5-bit code used in many types of data communications including teletype (TTY), radio teletype (RTTY),
and telecommunications devices for the deaf (TDD). Baudot code has been revised and extended
several times.
Bay
An opening in a computer cabinet that holds disk drives.
BBS
An acronym for bulletin board system, a computer that operates with a program and a modem to enable
other computers with modems to communicate with it, often on a round-the-clock basis. Thousands of
IBM- and Apple-related bulletin board systems offered a wealth of information and public-domain
software that can be downloaded in the era when they were in use.
Bezel
A cosmetic panel that covers the face of a drive or some other device.
Bezier Curve
A mathematical method for describing a curve, often used in illustration and CAD programs to draw
complex shapes.
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Bidirectional
Refers to lines over which data can move in two directions, like a data bus or a telephone line. Also refers
to the capability of a printer to print from right to left and from left to right
alternately.
Binary
Refers to the computer numbering system that consists of two numerals, 0 and 1. Also called base-2.
BIOS
Basic input-output system. The part of an operating system that handles the communications between
the computer and its peripherals. Often burned into read-only memory (ROM) chips.
Bisynchronous
Binary synchronous control. An earlier protocol developed by IBM for software applications and
communicating devices operation in synchronous environments. The protocol defines operations at the
link level of communications--for example, the format of data frames exchanged between modems over a
phone line.
Bit
A binary digit. Represented logically by 0 or 1 and electrically by 0 volts and (typically) 5 volts. Other
methods are used to represent binary digits physically (tones, different voltages, lights, and so on), but
the logic is always the same.
Bit Density
Expressed as Bits Per Inch (BPI), bit density defines how many bits can be written onto one linear inch of
a track. Sometimes also called linear density.
Bit map
A method of storing graphics information in memory in which a bit devoted to each pixel (picture element)
on-screen indicates whether that pixel is on or off. A bit map contains a bit for each point or dot on a video
display screen and allows for fine resolution because any point or pixel on-screen can be addressed. A
greater number of bits can be used to describe each pixel's color, intensity, and other display
characteristics.
Block
A string of records, words, or characters formed for technical or logic reasons and to be treated as an
entity.
Block diagram
The logical structure or layout of a system in graphics form. Does not necessarily match the physical
layout and does not specify all the components and their interconnections.
BNC
An acronym for British National Connector, a type of connector plug and jack system. Originally designed
in England for television set antennas, the BNC is a type of connector designed for use with coaxial
cabling. Male and female BNCs are available. Although the term is redundant, BNCs usually are
referred to as BNC connectors. Often used in local area network cabling systems that use coaxial cable,
such as EtherNet and ARCnet, and also used frequently for video cabling systems.
Boolean operation
Any operation in which each of the operands and the result take one of two values.
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Boot
Load a program into the PC. The term comes from the phrase "pulling up by the bootstrap."
Boot record
A one-sector record that tells the computer's built-in operating system (BIOS) the most fundamental facts
about a disk and DOS. Instructs the computer how to load the operating system files into memory, thus
booting the machine.
Bootstrap
A technique or device designed to bring itself into a desired state by means of its own action.
BPS
Bits per second. The number of binary digits, or bits, transmitted per second. Sometimes confused with
baud.
Bridge
In local area networks, an interconnection between two networks. Also the hardware equipment used to
establish such an interconnection.
Broadband
A term used to describe analog transmission. Requires modems for connecting terminals and computers
to the network. Using frequency division multiplexing, many different signals or sets of data can be
transmitted simultaneously. The alternate transmission scheme is baseband, or digital, transmission.
BTX
Stands for Balanced Technology eXtended, a form factor for motherboards and computer cases.
Bubble memory
A special type of nonvolatile read/write memory introduced by Intel in which magnetic regions are
suspended in crystal film and data is maintained when the power is off. A typical bubble memory chip
contains about 512K, or more than 4 million bubbles. Failed to catch on because of slow access times
measured in several milliseconds. Has found a niche use as solid-state disk emulators in environments in
which conventional drives are unacceptable, such as military or factory use.
Buffer
A block of memory used as a holding tank to store data temporarily. Often positioned between a slower
peripheral device and the faster computer. All data moving between the peripheral and the computer
passes through the buffer. A buffer enables the data to be read from or written to the peripheral in larger
chunks, which improves performance. A buffer that is x bytes in size usually holds the last x bytes of data
that moved between the peripheral and CPU. This method contrasts with that of a cache, which adds
intelligence to the buffer so that the most often accessed data rather than the last accessed data remains
in the buffer (cache). A cache can improve performance greatly over a plain buffer.
Bug
An error or defect in a program.
Burn-in
The operation of a circuit or equipment to stabilize components and to screen for failures.
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Bus
A linear electrical signal pathway over which power, data, and other signals travel and are capable of
connection to three or more attachments. A bus is generally considered to be distinct from radial or
point-to-point signal connections. The term bus comes from the Latin "omnibus" meaning "for all." When
used to describe a topology, bus always implies a linear structure.
Bus master
An intelligent device that when attached to the PCI bus can bid for and gain control of the bus to perform
its specific task.
Byte
A collection of bits that makes up a character or other designation. Generally, a byte is eight data bits plus
one parity (error-checking) bit.
Cache
An intelligent buffer. By using an intelligent algorithm, a cache contains the data that is accessed most
often between a slower peripheral device and the faster CPU.
CAM
An acronym for Common Access Method, a committee formed in 1988 consisting of a number of
computer peripheral suppliers and dedicated to developing standards for a common software interface
between SCSI peripherals and host adapters. The CAM committee also has set a standard for IDE drives
called the ATA interface.
Capacitor
A device consisting of two plates separated by insulating material and designed to store an electrical
charge.
Card
A printed circuit board containing electronic components that form an entire circuit, usually designed to
plug into a connector or slot. Sometimes also called an adapter.
Carpal tunnel syndrome
A painful hand injury that gets its name from the narrow tunnel in the wrist which connects ligament and
bone. When undue pressure is put on the tendons, they can swell and compress the median nerve, which
carries impulses from the brain to the hand, causing numbness, weakness, tingling, and burning in the
fingers and hands. Computer users get carpal tunnel syndrome primarily from improper keyboard
ergonomics that result in undue strain on the wrist and hand.
Carrier
A continuous frequency signal capable of being either modulated or impressed with another
information-carrying signal. The reference signal used for the transmission or reception of data. The most
common use of this signal with computers involves modem communications over phone lines. The carrier
is used as a signal on which the information is superimposed.
Carrier detect signal
A modem interface signal which indicates to the attached data terminal equipment (DTE) that it is
receiving a signal from the distant modem. Defined in the RS-232 specification. Same as the received
line-signal detector.
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CAT3, CAT5, CAT5e, CAT6, CAT6e and CAT7 cable
CAT is short for the word “category”; each of these categories of twisted pair cables have different datacarrying capacities. For example, CAT5 cable can safely transmit 10megabits per second (10Mbps),
CAT5e can transmit 100Mbps, CAT6 can transmit up to 1000Mbps, or a Gigabit per second. CAT5 and
CAT6 cables can transmit data up to 100 meters, or 330 feet. CAT7 cable can transmit data further than
CAT6 cables, and the “e” designations indicate that the cables have additional shielding to prevent
signal loss or distortion.
Cathode ray tube
A device that contains electrodes surrounded by a glass sphere or cylinder and displays information by
creating a beam of electrons that strike a phosphor coating inside the display unit.
CAV
CAV is an acronym for Constant Angular Velocity, an optical disk recording format where the data is
recorded on the disk in concentric circles. CAV disks are rotated at a constant speed. This is similar to the
recording technique used on floppy disk drives. CAV limits the total recorded capacity compared to CLV
(Constant Linear Velocity), which is also used in optical recording.
CCFL
Stands for Cold Cathode Fluorescent Lamp.
CCITT
An acronym for the Comite Consultatif Internationale de Telegraphique et Telephonique (in English, the
International Telegraph and Telephone Consultative Committee or the Consultative Committee for
International Telegraph and Telephone). An international committee organized by the United Nations to
set international communications recommendations, which frequently are adopted as standards, and to
develop interface, modem, and data network recommendations. The Bell 212A standard for 1200 bps
communication in North America, for example, is observed internationally as CCITT V.22. For 2400 bps
communication, most U.S. manufacturers observe V.22bis, and V.32 and V.32bis are standards for 9600
and 14400 bps, respectively. Work is now under way to define a new standard for 19200 bps called
V.32fast.
CCS
An acronym for the Common Command Set, a set of SCSI commands specified in the ANSI SCSI-1
Standard X3.131-1986 Addendum 4.B. All SCSI devices must be capable of using the CCS in order to be
fully compatible with the ANSI SCSI-1 standard.
CD-DA
CD-DA is an acronym for Compact Disc Digital Audio. CD-DA is also known as "Red Book Audio", and is
the digital sound format used by audio CDs. CD-DA uses a sampling rate of 44.1KHz and stores 16 bits of
information for each sample. CD audio is not played through the computer, but through a special chip in
the CD-ROM drive. Fifteen minutes of CD-DA sound can require about 80 MB. The highest quality sound
that can be utilized by Multimedia PC is the CD-DA format at 44.1KHz sample rate.
CD-R
CD-R is an acronym for Compact Disk Recordable, sometimes also called CD-Writable. CD-R disks are
compact disks that can be recorded several times and read as many times as desired. CD-R is part of the
Orange Book Standard defined by ISO. CD-R technology is used for mass production of multimedia
applications. CD-R disks can be compatible with CD-ROM, CD-ROM XA and CD audio. Orange Book
specifies multi-session capabilities, which allows data recording on the disk at different times in several
recording sessions. Kodak's Photo CD is an example of CD-R technology, and fits up to 100 digital
photographs on a single CD. Multi-session capability allows several rolls of 35MM film to be added to a
single disk on different occasions.
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CD-ROM
An acronym for compact disc read-only memory. A computer peripheral device that employs compact
disc (CD) technology to store large amounts of data for later retrieval. Phillips and Sony developed
CD-ROM in 1983. Current CD-ROM discs hold approximately 600M of information. CD-ROM drives are
much slower than conventional hard disks, with normal average-access times of 380 milliseconds or
greater and data transfer rates of about 1.2 megabits per second. Most CD-ROM drives use the IDE or
SATA interface bus for connection to a system.
CD-ROM XA
CD-ROM XA is an acronym for Compact Disk Read Only Memory eXtended Architecture. The XA
standard was developed jointly by Sony, Philips and Microsoft in 1988 and is now part of the Yellow Book
Standard. XA is a built in feature of newer CD-ROM drives which supports simultaneous sound playback
with data transfer. Non-XA drives support either sound playback OR data transfer, but not both
simultaneously. XA also provides for data compression right on the disk, which can also increase data
transfer rates.
CDFS
Stands for Compact Disc File System, which is the method used to store data onto optical discs.
Ceramic substrate
A thin, flat, fired ceramic part used to hold an IC chip (usually made of beryllium oxide or aluminum oxide).
CFS
Stands for Central File System, Common File System, and/or Command File System.
CGA
An acronym for Color Graphics Adapter, a type of PC video display adapter introduced by IBM on August
12, 1981, that supports text and graphics. Text is supported at a maximum resolution of 80x25 characters
in 16 colors with a character box of 8x8 pixels. Graphics is supported at a maximum resolution of
320x200 pixels in 16 colors or 640x200 pixels in 2 colors. The CGA outputs a TTL (digital) signal with a
horizontal scanning frequency of 15.75 KHz, and supports TTL color or NTSC composite displays. See
also pixel.
Channel
A path along which signals can be sent.
Character
A representation, coded in binary digits, of a letter, number, or other symbol.
Checksum
Short for summation check, a technique for determining whether a package of data is valid. The package,
a string of binary digits, is added up and compared with the expected number.
Chip
Another name for an IC, or integrated circuit. Housed in a plastic or ceramic carrier device with pins for
making electrical connections. See also ceramic substrate and chip carrier.
Chip carrier
A ceramic or plastic package that carries an integrated circuit, or IC.
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CIDR
Classless Inter-Domain Routing (CIDR) is a method for allocating IP addresses and routing Internet
Protocol packets. The Internet Engineering Task Force introduced CIDR in 1993 to replace the
previous addressing architecture of classful network design in the Internet. Its goal was to slow the
growth of routing tables on routers across the Internet, and to help slow the rapid exhaustion of IPv4
addresses. Classless Inter-Domain Routing allocates address space to Internet service providers and
end users on any address bit boundary, instead of on 8-bit segments. In IPv6, however, the interface
identifier has a fixed size of 64 bits by convention, and smaller subnets are never allocated to end
users.
CIFS
Stands for Common Internet File System
Circuit
A complete electronic path.
Circuit board
The collection of circuits gathered on a sheet of plastic, usually with all electrical contacts made through a
strip of pins. The circuit board usually is made by chemically etching metal-coated plastic.
CISC
An acronym for complex instruction-set computer. Refers to traditional computers that operate with large
sets of processor instructions. Most modern computers, including the Intel 80xxx processors, are in this
category. CISC processors have expanded instruction sets that are complex in nature and require
several to many execution cycles to complete. This structure contrasts with RISC (reduced instruction-set
computer) processors, which have far fewer instructions that execute quickly.
Clean room
A dust-free room in which certain electronic components (such as hard disk drives) must be
manufactured and serviced to prevent contamination. Rooms are rated by Class numbers. A Class 100
clean room must have fewer than 100 particles larger than .5 microns per cubic foot of space.
Clock
The source of a computer's timing signals. Synchronizes every operation of the CPU.
Clock speed
A measurement of the rate at which the clock signal for a device oscillates, usually expressed in millions
of cycles per second (MHz).
Clone
An IBM-compatible computer system that physically as well as electrically emulates the design of one of
IBM's personal computer systems, usually the AT or XT. For example, an AT clone has parts
(motherboard, power supply, and so on) that are physically interchangeable with the same parts in the
IBM AT system.
Cluster
Also called allocation unit. A group of sectors on a disk that forms a fundamental unit of storage to the
operating system. Cluster or allocation unit size is determined by DOS when the disk is formatted.
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CLV
CLV is an acronym for Constant Linear Velocity, an optical recording format where the spacing of data is
consistent throughout the disk, and the rotational speed of the disk varies depending on what track is
being read. Additionally, more sectors of data are placed on the outer tracks compared to the inner tracks
of the disk, which is similar to Zone Recording on hard drives. CLV drives will adjust the rotational speed
to maintain a constant track velocity as the diameter of the track changes. CLV drives rotate faster near
the center of the disk and slower towards the edge. Rotational adjustment maximizes the amount of data
that can be stored on a disk. CD-DA audio and CD-ROM use CLV recording.
CMOS
Complementary Metal-Oxide Semiconductor. A type of chip design that requires little power to operate. In
an AT-type system, a battery-powered CMOS memory and clock chip is used to store and maintain the
clock setting and system configuration information.
CNR
Stands for Communications and Networking Riser, a type of bus connection and card used on
motherboards to allow networking and modem communications.
Coated media
Hard disk platters coated with a reddish iron-oxide medium on which data is recorded.
Coaxial cable
Coaxial cable, or coax, is a type of cable that has an inner conductor surrounded by a tubular insulating
layer, surrounded by a tubular conducting shield. Many coaxial cables also have an insulating outer
sheath or jacket. The term coaxial comes from the inner conductor and the outer shield sharing a
geometric axis. Coaxial cable differs from other shielded cable used for carrying lower-frequency
signals. The dimensions of the cable are controlled to give a precise, constant conductor spacing,
which is needed for it to function efficiently as a transmission line. RG-6 cable has two layers of
shielding, and RG-59 cable has a single layer of shielding.
COBOL
An acronym for Common business-oriented language, a high-level computer programming language.
The business world's preferred programming language on mainframe computer systems, it has never
achieved popularity on smaller computers.
Code page switching
A DOS feature in versions 3.3 and later that changes the characters displayed on-screen or printed on an
output device. Primarily used to support foreign-language characters. Requires an EGA or better video
system and an IBM-compatible graphics printer.
Coercivity
A measurement in units of oersteads of the amount of magnetic energy to switch or coerce the flux
change in the magnetic recording media. High-coercivity disk media requires a stronger write current.
COM port
A port on a PC that conforms to the RS-232 standard.
Command
An instruction that tells the computer to start, stop, or continue an operation.
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COMMAND.COM
An operating system file that is loaded last when the computer is booted. The command interpreter or
user interface and program-loader portion of DOS.
Common
The ground or return path for an electrical signal. If a wire, usually is colored black.
Common mode noise
Noise or electrical disturbances that can be measured between a current- or signal-carrying line and its
associated ground. Common mode noise is frequently introduced to signals between separate computer
equipment components through the power distribution circuits. It can be a problem when single-ended
signals are used to connect different equipment or components that are powered by different circuits.
Compiler
A program that translates a program written in a high-level language into its equivalent machine
language. The output from a compiler is called an object program.
Composite video
Television picture information and sync pulses combined. The IBM Color Graphics Adapter (CGA)
outputs a composite video signal.
Computer
Device capable of accepting data, applying prescribed processes to this data, and displaying the results
or information produced.
CONFIG.SYS
A file that can be created to tell DOS how to configure itself when the machine starts up. Can load device
drivers, set the number of DOS buffers, and so on.
Configuration file
A file kept by application software to record various aspects of the software's configuration, such as the
printer it uses.
Console
The unit, such as a terminal or a keyboard, in your system with which you communicate with the
computer.
Contiguous
Touching or joined at the edge or boundary, in one piece.
Continuity
In electronics, an unbroken pathway. Testing for continuity normally means testing to determine whether
a wire or other conductor is complete and unbroken (by measuring 0 ohms). A broken wire shows infinite
resistance (or infinite ohms).
Control cable
The wider of the two cables that connect an ST-506/412 or ESDI hard disk drive to a controller card. A
34-pin cable that carries commands and acknowledgments between the drive and controller.
Controller
The electronics that control a device such as a hard disk drive and intermediate the passage of data
between the device and the computer.
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Controller card
An adapter holding the control electronics for one or more devices such as hard disks. Ordinarily
occupies one of the computer's slots, or is built into the motherboard.
Convergence
Describes the capability of a color monitor to focus the three colored electron beams on a single point.
Poor convergence causes the characters on-screen to appear fuzzy and can cause headaches and
eyestrain.
Coprocessor
An additional computer processing unit designed to handle specific tasks in conjunction with the main or
central processing unit. See also CPU.
Core
An old-fashioned term for computer memory.
CP/M
An acronym for Control Program/Microcomputer, an operating system created by Gary Kildall, the
founder of Digital Research. Created for the old 8-bit microcomputers that used the 8080, 8085, and Z-80
microprocessors. Was the dominant operating system in the late 1970s and early 1980s for small
computers used in a business environment.
CPS
Characters per second. A data transfer rate generally estimated from the bit rate and the character
length. At 2400 bps, for example, 8-bit characters with start and stop bits (for a total of 10 bits per
character) are transmitted at a rate of approximately 240 characters per second (cps). Some protocols,
such as V.42 and MNP, employ advanced techniques such as longer transmission frames and data
compression to increase cps.
CPU
Central processing unit. The computer's microprocessor chip, the brains of the outfit. Typically, an IC
using VLSI (very-large-scale integration) technology to pack several different functions into a tiny area.
The most common electronic device in the CPU is the transistor, of which several thousand to several
million or more are found.
Crash
A malfunction that brings work to a halt. A system crash usually is caused by a software malfunction, and
ordinarily you can restart the system by rebooting the machine. A head crash, however, entails physical
damage to a disk and probable data loss.
CRC
An acronym for cyclic redundancy checking, an error-detection technique consisting of a cyclic algorithm
performed on each block or frame of data by both sending and receiving modems. The sending modem
inserts the results of its computation in each data block in the form of a CRC code. The receiving modem
compares its results with the received CRC code and responds with either a positive or negative
acknowledgment. In the ARQ protocol implemented in high-speed modems, the receiving modem
accepts no more data until a defective block is received correctly.
Crosstalk
The electromagnetic coupling of a signal on one line with another nearby signal line. Cross talk is caused
by electromagnetic induction, where a signal traveling through a wire creates a magnetic field that then
induces a current in other nearby wires.
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CRT
Cathode-ray tube. A term used to describe a television or monitor screen tube.
Current
The flow of electrons, measured in amperes. See ampere.
Cursor
The small flashing hyphen that appears on-screen to indicate the point at which any input from the
keyboard will be placed.
Cylinder
The set of tracks on a disk that are on each side of all the disk platters in a stack and are the same
distance from the center of the disk. The total number of tracks that can be read without moving the
heads. A floppy drive with two heads usually has 160 tracks, which are accessible as 80 cylinders. A
typical 20M hard disk has 2 platters with 4 heads and 615 cylinders, in which each cylinder is 4 tracks.
Daisy chain
Stringing up components in such a manner that the signals move serially from one to the other. Most
microcomputer multiple disk drive systems are daisy-chained. The SCSI bus system is a daisy-chain
arrangement, in which the signals move from computer to disk drives to tape units, and so on.
Daisywheel printer
An impact printer that prints fully formed characters one at a time by rotating a circular print element
composed of a series of individual spokes, each containing two characters that radiate from a center hub.
Produces letter-quality output.
DAT
An acronym for digital audio tape, a small cassette tape for storing large amounts of digital information.
Also sometimes called 4mm tape. DAT technology emerged in Europe and Japan in 1986 as a way to
produce high-quality, digital audio recordings. One DAT cassette can hold approximately 1.3 gigabytes of
data.
Data
Groups of facts processed into information. A graphic or textural representation of facts, concepts,
numbers, letters, symbols, or instructions used for communication or processing.
Data cable
Any cable that connects a hard disk or CD/DVD drive to a controller interface or card.
Data communications
A type of communication in which computers and terminals can exchange data over an electronic
medium.
Data compression
Data compression is a technique where mathematical algorithms are applied to the data in a file to
eliminate redundancies and therefore reduce the size of the file. There are two types of compression:
Lossy and Lossless. Lossy compression deletes some of the original (uncompressed) data needed to
reconstruct a file, and is normally used only for graphic image or sound files, where the loss of some
resolution or information is acceptable. Lossless compression maintains completely the integrity of the
original file, allowing it to be reconstructed exactly, and is most commonly used for program or data files.
DAC
Stands for Digital-to-Analog Converter, or for Discretionary Access Control.
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Data separator
A device that separates data and clock signals from a single encoded signal pattern. Usually the same
device does both data separation and combination and is sometimes called an "endec" for
Encoder/Decoder.
Data transfer rate
The maximum rate at which data can be transferred from one device to another.
DB-9 and DB-25
Stands for serial communications D-shell, either a 9-pin or 25-pin connector.
DC
Direct current, such as that provided by a power supply or batteries.
DC-600
Data Cartridge 600, a data-storage medium invented by 3M in 1971 that uses a quarter-inch-wide tape
600 feet in length.
DCE
Data communications equipment. The hardware that does the communication; usually a dial-up modem
that establishes and controls the data link through the telephone network. See also DTE.
DDE
An acronym for Dynamic Data Exchange, a form of inter-process communications used by Microsoft
Windows to support the exchange of commands and data between two applications running
simultaneously. This capability has been enhanced further with Object Linking and Embedding (OLE).
DDOS
Stands for Distributed Denial Of Service, a type of hacking attack against web hosts on the Internet.
DDR
Stands for Double-Data-Rate, a type of random access Memory (RAM) or synchronous dynamic random
access memory (SDRAM).
DEBUG
The name of a utility program included with DOS and used for specialized purposes such as altering
memory locations, tracing program execution, patching programs and disk sectors, and performing other
low-level tasks.
Dedicated line
A user-installed telephone line used to connect a specified number of computers or terminals within a
limited area, such as a single building. The line is a cable rather than a public-access telephone line. The
communications channel also may be referred to as non-switched because calls do not go through
telephone company switching equipment.
Dedicated servo surface
In voice-coil-actuated hard disk drives, one side of one platter given over to servo data that is used to
guide and position the read/write heads.
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Default
Any setting assumed at start-up or reset by the computer's software and attached devices and
operational until changed by the user. An assumption the computer makes when no other parameters are
specified. When you type DIR without specifying the drive to search, for example, the computer assumes
that you want it to search the default drive. The term is used in software to describe any action the
computer or program takes on its own with imbedded values.
Density
The amount of data that can be packed into a certain area on a specific storage media.
Device driver
A memory-resident program, loaded by CONFIG.SYS, that controls a device, such as a CD-ROM drive or
network interface card.
DFS
Stand for Distributed File System.
DHCP
Stands for Dynamic Host Configuration Protocol, which distributes dynamically-assigned IP addresses to
computers or devices on a network.
Dhrystone
A benchmark program used as a standard figure of merit indicating aspects of a computer system's
performance in areas other than floating-point math performance. Because the program does not use
any floating-point operations, performs no I/O, and makes no operating system calls, it is most applicable
to measuring the processor performance of a system. The original Dhrystone program was developed in
1984 and was written in Ada, although the C and Pascal versions became more popular by 1989.
Diagnostics
Programs used to check the operation of a computer system. These programs enable the operator to
check the entire system for any problems and to indicate in what area the problems lie.
Differential
An electrical signaling method where a pair of lines are used for each signal in "push-pull" fashion. In
most cases differential signals are balanced so that the same current flows on each line in opposite
directions. This is unlike Single-ended signals which use only one line per signal referenced to a single
ground. Differential signals have a large tolerance for common-mode noise, and little cross-talk when
used with twisted pair wires even in long cables. Differential signaling is expensive because two pins are
required for each signal.
Digital loopback
A test that checks the RS-232 interface on a modem and the cable that connects the terminal or computer
and the modem. The modem receives data (in the form of digital signals) from the computer or terminal
and immediately returns the data to the screen for verification.
Digital signals
Discrete, uniform signals. In this book, the term refers to the binary digits 0 and 1.
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Digitize
Digitizing refers to transforming an analog wave to a digital signal that a computer can store. Conversion
to digital data and back is performed by a Digital to Analog Converter (DAC), often a single chip device.
How closely a digitized sample represents an analog wave depends on the number of times the
amplitude of a wave is measured and recorded, or the rate of digitization, as well as the number of
different levels that can be specified at each instance. The number of possible signal levels is dictated by
the resolution in bits.
DIMM
Dual in-line memory module. An array of memory chips on a small PC board with 2 rows of I/O contacts.
DIN
Stands for Deutsche Industrie Norm.
DIP
Dual In-line Package. A family of rectangular, integrated-circuit flat packages that have leads on the two
longer sides. Package material is plastic or ceramic.
DIP switch
A tiny switch (or group of switches) on a circuit board. Named for the form factor of the carrier device in
which the switch is housed.
Direct memory access (or DMA)
A process by which data moves between a disk drive (or other device) and system memory without direct
control of the central processing unit (CPU), thus freeing it up for other tasks.
Directory
An area of a disk that stores the titles given to the files saved on the disk and serves as a table of contents
for those files. Contains data that identifies the name of a file, the size, the attributes (system, hidden,
read-only, and so on), the date and time of creation, and a pointer to the location of the file. Each entry in
a directory is 32 bytes long.
Dithering
Dithering is the process of creating more colors and shades from a given color palette. In monochrome
displays or printers, dithering will vary the black and white dot patterns to simulate shades of gray. Gray
scale dithering is used to produce different shades of gray when the device can only produce limited
levels of black or white outputs. Color screens or printers use dithering to create colors by mixing and
varying the dot sizing and spacing.
DLL
An acronym for Dynamic Link Library, an executable driver program module for Microsoft Windows that
can be loaded on demand and linked in at run time, and subsequently unloaded when the driver is no
longer needed.
DLP
Stands for Digital Light Processing, and also Data Loss Prevention.
DLT
Stands for Digital Linear Tape.
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Diskette
A floppy disk. Made of a flexible material coated with a magnetic substance, the disk spins inside its
protective jacket, and the read/write head comes in contact with the recording surface to read or write
data.
DMA
Direct memory access. A circuit by which a high-speed transfer of information may be facilitated between
a device and system memory. This transfer is managed by a specialized processor that relieves the
burden of managing the transfer from the main CPU.
DMZ
Stands for Demilitarized Zone; a physical or logical subnetwork that contains and exposes an
organization's external-facing services to a larger and untrusted network, usually the Internet.
DNS
Stands for Domain Name Service or Domain Name Server.
DOS
An acronym for disk operating system. A collection of programs stored on the DOS disk that contain
routines enabling the system and user to manage information and the hardware resources of the
computer. DOS must be loaded into the computer before other programs can be started.
Dot pitch
A measurement of the width of the dots that make up a pixel. The smaller the dot pitch, the sharper the
image.
Dot-matrix printer
An impact printer that prints characters composed of dots. Prints characters one at a time by pressing the
ends of selected wires against an inked ribbon and paper.
Double density (DD)
An indication of the storage capacity of a floppy drive or disk in which eight or nine sectors per track are
recorded using MFM encoding.
Down-time
Operating time lost because of a computer malfunction.
DPMI
An acronym for DOS Protected Mode Interface, an industry standard interface that allows DOS
applications to execute program code in the protected mode of the 286 or higher Intel processor. The
DPMI specification is available from Intel.
Drive
A mechanical device that manipulates data storage media.
DRAM
Stands for Dynamic Random Access Memory.
DRM
Digital Rights Management is a technology that seeks to prevent the unauthorized copying and
distribution of copyrighted materials in electronic format.
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DSL
Stands for Digital Subscriber Line; also called asynchronous digital subscriber line; a method of
providing Internet access through traditional telephone lines.
DTE
Data terminal (or terminating) equipment. The device, usually a computer or terminal, that generates or is
the final destination of data. See also DCE.
Duplex
Indicates a communications channel capable of carrying signals in both directions.
DVD
Stands for Digital Video Disc or Digital Versatile Disc.
DVD-RAM
Stands for Digital Video Disc – Random Access Memory.
DVD-RAM
Stands for Digital Video Disc – Read Only Memory.
DVD-R
Stands for Digital Video Disc – Recordable
DVD-RW
Stands for Digital Video Disc – Rewritable
DVI
DVI is an acronym for Digital Video Interactive, a standard that was originally developed at RCA
Laboratories, and sold to Intel in 1988. DVI integrates digital motion, still video, sound, graphics and
special effects in a compressed format. DVI is a highly sophisticated hardware compression technique
used in interactive multimedia applications.
Dvorak keyboard
A keyboard design by August Dvorak that was patented in 1936 and approved by ANSI in 1982. Provides
increased speed and comfort and reduces the rate of errors by placing the most frequently used letters in
the center for use by the strongest fingers. Finger motions and awkward strokes are reduced by more
than 90 percent in comparison with the familiar QWERTY keyboard. The Dvorak keyboard has the five
vowel keys, AOEUI, together under the left hand in the center row, and the five most frequently used
consonants, DHTNS, under the fingers of the right hand.
EBCDIC
An acronym for Extended Binary Coded Decimal Interchange Code, an IBM developed 8-bit code for the
representation of characters. It allows 256 possible character combinations within a single byte. EBCDIC
is the standard code on IBM mini-computers and mainframes, but not on the IBM microcomputers, where
ASCII is used instead.
ECC
Stands for Error Correction Code, used in modem and network communications.
ECP
Stands for Extended Capabilities Port, a mode of data transfer on 25-pin parallel ports.
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EEPROM
Stands for Electrically-Erasable Programmable Read-Only Memory.
Edit
The process of rearranging data or information.
EFS
Stands for Encrypting File System.
EGA
An acronym for Enhanced Graphics Adapter, a type of PC video display adapter first introduced by IBM
on September 10, 1984, that supports text and graphics. Text is supported at a maximum resolution of
80x25 characters in 16 colors with a character box of 8x14 pixels. Graphics is supported at a maximum
resolution of 640x350 pixels in 16 (from a palette of 64) colors. The EGA outputs a TTL (digital) signal
with a horizontal scanning frequency of 15.75, 18.432, or 21.85 KHz, and supports TTL color or TTL
monochrome displays.
EIA
Electronic Industries Association, which defines electronic standards in the United States.
EIDE
Stands for Enhanced Integrated Drive Electronics, a type of hard drive and disk interface.
EISA
An acronym for Extended Industry Standard Architecture, an extension of the Industry Standard
Architecture (ISA) bus developed by IBM for the AT. The EISA design was led by COMPAQ
Corporation. Later, eight other manufacturers (AST, Epson, Hewlett-Packard, NEC, Olivetti, Tandy,
Wyse, and Zenith) joined COMPAQ in a consortium founded September 13, 1988. This group became
known as the "gang of nine." The EISA design was patterned largely after IBMÆs Micro Channel
Architecture (MCA) in the PS/2 systems, but unlike MCA, EISA allows for backward compatibility with
older plug-in adapters.
Electronic mail / E-mail
A method of transferring messages form one computer to another.
Electrostatic discharge (ESD)
Static electricity, a sudden flow of electricity between two objects at different electrical potentials. ESD is
a primary cause of integrated circuit damage or failure.
Embedded servo data
Magnetic markings embedded between or inside tracks on disk drives that use voice-coil actuators.
These markings enable the actuator to fine-tune the position of the read/write heads.
EMI
Stands for Electro-Magnetic Interference.
EMM
An acronym for Expanded Memory Manager, a driver that provides a software interface to expanded
memory. EMMs were originally created for expanded memory boards, but can also use the memory
management capabilities of the 386 or higher processors to emulate an Expanded Memory board.
EMM386.EXE is an example of an EMM that comes with DOS.
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EMP
Stands for Electro-Magnetic Pulse, which can destroy electronic equipment.
EMS
An acronym for Expanded Memory Specification. Sometimes also called the LIM spec. because it was
developed by Lotus, Intel, and Microsoft. Provides a way for microcomputers running under DOS to
access additional memory. EMS memory management provides access to a maximum of 32M of
expanded memory through a small (usually 64K) window in conventional memory. EMS is a cumbersome
access scheme designed primarily for pre-286 systems that could not access extended memory.
Emulator
A piece of test apparatus that emulates or imitates the function of a particular chip.
Encoding
The protocol by which data is carried or stored by a medium.
Encryption
The translation of data into unreadable codes to maintain security.
Endec (Encoder/Decoder)
A device that takes data and clock signals and combines or encodes them using a particular encoding
scheme into a single signal for transmission or storage. The same device also later separates or decodes
the data and clock signals during a receive or read operation. Sometimes called a Data separator.
EPROM
Erasable programmable read-only memory. A type of read-only memory (ROM) in which the data pattern
can be erased to allow a new pattern. Usually is erased by ultraviolet light and recorded by a higher than
normal voltage programming signal.
EPP
Stands for Enhanced Parallel Port, a mode of data transfer on 25-pin parallel ports.
Equalization
A compensation circuit designed into modems to counteract certain distortions introduced by the
telephone channel. Two types are used: fixed (compromise) equalizers and those that adapt to
channel conditions (adaptive). Good-quality modems use adaptive equalization.
ERD
Stands for Emergency Repair Disk, which is created using Windows Backup.
Error control
Various techniques that check the reliability of characters (parity) or blocks of data. V.42, MNP, and HST
error-control protocols use error detection (CRC) and retransmission of errored frames (ARQ).
Error message
A word or combination of words to indicate to the user that an error has occurred somewhere in the
program.
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ESD
Stands for Electro-Static Discharge, which can damage sensitive electronic components.
ESDI
An acronym for Enhanced Small Device Interface, a hardware standard developed by Maxtor and
standardized by a consortium of 22 disk drive manufacturers on January 26, 1983. A group of 27
manufacturers formed the ESDI steering committee on September 15, 1986, to enhance and improve the
specification. A high-performance interface used primarily with hard disks, ESDI provides for a maximum
data transfer rate to and from a hard disk of between 10 and 24 megabits per second.
EtherNet
A type of network protocol developed in the late 1970s by Bob Metcalf, at Xerox Corporation, and
endorsed by the IEEE. One of the oldest LAN communications protocols in the personal computing
industry. EtherNet networks use a collision-detection protocol to manage contention.
EULA
Stands for End-User Licensing Agreement, which dictates how an software application or operating
system can be installed and used.
EVGA
Stands for Extended Video Graphics Array (or Adapter), a type of video card and display format.
EV-DO
Stands for Evolution Data Optimized, a method of sending data to/from the Internet using cellular data
distribution systems.
Expanded memory
Otherwise known as EMS memory, memory that conforms to the EMS specification. Requires a special
device driver and conforms to a standard developed by Lotus, Intel, and Microsoft.
Extended memory
Direct processor-addressable memory that is addressed by an Intel (or compatible) 286, 386, 486 or
Pentium processor in the region beyond the first megabyte. Addressable only in the processor's
protected mode of operation.
Extended partition
A non-bootable DOS partition containing DOS volumes. Starting with DOS V3.3, the DOS FDISK
program can create two partitions that serve DOS: an ordinary, bootable partition (called the primary
partition) and an extended partition, which may contain as many as 23 volumes from D: through Z:.
Extra-high density (ED)
An indication of the storage capacity of a floppy drive or disk in which 36 sectors per track are recorded
using a vertical recording technique with MFM encoding.
FAT
Stands for File Allocation Table; a means of listing filename data and data locations on a disc.
FAT-12
Stands for 12-bit File Allocation Table; used with floppy disks.
FAT-16
Stands for 16-bit File Allocation Table; maximum partition size is 2GB.
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FAT-32
Stands for 32-bit File Allocation Table; maximum partition size is 4TB.
FDD
Stands for Floppy Disk Drive.
FIFO
An acronym for first-in first-out, a method of storing and retrieving items from a list, table, or stack such
that the first element stored is the first one retrieved.
File
A collection of information kept somewhere other than in random-access memory.
File allocation table
A table held near the outer edge of a disk that tells which sectors are allocated to each file and in what
order.
File attribute
Information held in the attribute byte of a file's directory entry.
File defragmentation
The process of rearranging disk sectors so that files are compacted on consecutive sectors in adjacent
tracks.
File name
The name given to the disk file. Must be one to eight characters long and may be followed by a file-name
extension, which can be one to three characters long. Can be made up of any combination of letters and
numbers but should be descriptive of the information contained in the file. Starting with Windows95,
filenames can be as many as 255 characters in length.
Firmware
Software contained in a read-only memory (ROM) device. A cross between hardware and software.
Fixed disk
Also called a hard disk, a disk that cannot be removed from its controlling hardware or housing. Made of
rigid material with a magnetic coating and used for the mass storage and retrieval of
data.
Floppy tape
A tape standard that uses drives connecting to an ordinary floppy disk controller.
Flow control
A mechanism that compensates for differences in the flow of data input to and output from a modem or
other device.
FM encoding
Frequency modulation encoding. An outdated method of encoding data on the disk surface that uses up
half the disk space with timing signals.
Form factor
The physical dimensions of a device. Two devices with the same form factor are physically
interchangeable. The IBM PC, XT, and XT Model 286, for example, all use power supplies that are
internally different but have exactly the same form factor.
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FORMAT.COM
The DOS format program that performs both low- and high-level formatting on floppy disks but only
high-level formatting on hard disks.
Formatted capacity
The total number of bytes of data that can fit on a formatted disk. The unformatted capacity is higher
because space is lost defining the boundaries between sectors.
Formatting
Preparing a disk so that the computer can read or write to it. Checks the disk for defects and constructs
an organizational system to manage information on the disk.
FORTRAN
An acronym for formula translator, a high-level programming language for programs dealing primarily
with mathematical formulas and expressions, similar to algebra and used primarily in scientific and
technical applications. One of the oldest languages but still widely used because of its compact notation,
the many mathematical subroutines available, and the ease with which arrays, matrices, and loops can
be handled. FORTRAN was written in 1954 by John Backus at IBM, and the first successful FORTRAN
program was executed by Harlan Herrick.
FPM
Stands for Fast-Page Mode, a means of reading/writing data in RAM.
FQDN
Stands for Fully Qualified Domain Name.
Frame
A data communications term for a block of data with header and trailer information attached. The added
information usually includes a frame number, block size data, error-check codes, and start/end
indicators.
Freeware
Copyrighted software given away for free by the author. Although it is available for free, the author retains
the copyright, which means that you cannot do anything with it that is not expressly allowed by the author.
Usually, the author allows people to use the software, but not sell it.
FRU
Stands for Field Replaceable Unit, or a spare/replacement part.
FSB
Stands for Front-Side Bus, the data path between the CPU and RAM.
FTP
Stands for File Transfer Protocol, a part of the TCP/IP suite of applications.
Full duplex
Signal flow in both directions at the same time. In microcomputer communications, also may refer to the
suppression of the on-line local echo.
Full-height drive
A drive unit that is 3.25 inches high, 5.75 inches wide, and 8.00 inches deep.
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Function keys
Special-purpose keys that can be programmed to perform various operations. Serve many different
functions depending on the program being used.
Gas-plasma display
Commonly used in portable systems, a type of display that operates by exciting a gas, usually neon or an
argon-neon mixture, through the application of a voltage. When sufficient voltage is applied at the
intersection of two electrodes, the gas glows an orange-red. Because gas-plasma displays generate
light, they require no backlighting.
Gateway
A node on a network that serves as an entrance to another network. In enterprises, the gateway is the
computer that routes the traffic from a workstation to the outside network that is serving the Web pages.
In homes, the gateway is the ISP that connects the user to the internet.
In enterprises, the gateway node often acts as a proxy server and a firewall. The gateway is also
associated with both a router, which use headers and forwarding tables to determine where packets are
sent, and a switch, which provides the actual path for the packet in and out of the gateway.
GDI
Stands for Graphics Device Interface.
GHz
Stands for Gigahertz, a measurement of speed by a wavelength.
Giga
A multiplier indicating 1 billion (1,000,000,000) of some unit. Abbreviated as g or G. When used to
indicate a number of bytes of memory storage, the multiplier definition changes to 1,073,741,824. One
gigabit, for example, equals 1,000,000,000 bits, and one gigabyte equals 1,073,741,824 bytes.
Gigabyte (GB)
A unit of information storage equal to 1,073,741,824 bytes. A gigabit (Gb) is 1 billion bits of data.
Global backup
A backup of all information on a hard disk, including the directory tree structure.
Green Book
Green Book is the standard for Compact Disc-Interactive (CD-I). Philips developed CD-I technology for
the consumer market, to be connected to a television instead of a computer monitor. CD-I is not a
computer system, but a consumer device. CD-I disks require special code and are not compatible with
standard CD-ROM. A CD-ROM cannot be played on the CD-I machine, but Red Book audio can be
played on CD-I devices.
GPS
Stands for Global Positioning Satellite (or System).
GSM
Stands for Global System for mobile Communications, a data communications mode for cellular devices.
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GUI
An acronym for Graphical User Interface, a type of program interface that allows users to choose
commands and functions by pointing to a graphical icon using either a keyboard or pointing
device such as a mouse. Windows and OS/2 are popular GUIs available for PC systems.
HAL
Stands for Hardware Abstraction Layer, used by the Windows operating system to create a similar
platform on various kinds of hardware devices.
Half duplex
Signal flow in both directions but only one way at a time. In microcomputer communications, may refer to
activation of the on-line local echo, which causes the modem to send a copy of the transmitted data to the
screen of the sending computer.
Half-height drive
A drive unit that is 1.625 inches high, and either 5.75 or 4.00 inches wide and 4.00 or 8.00 inches deep.
Halftone
Halftoning is a process that uses dithering to simulate a continuous tone image such as a photograph or
shaded drawing using various sizes of dots. Newspapers, magazines and many books use halftoning.
The human eye will merge the dots to give the impression of gray shades.
Hard disk
A high-capacity disk storage unit characterized by a normally non-removable rigid substrate media. The
platters in a hard disk normally are constructed of aluminum or glass.
Hard error
An error in reading or writing data that is caused by damaged hardware.
Hardware
Physical components that make up a microcomputer, monitor, printer, and so on.
HAV
Stands for Hardware-Assisted Virtualization.
HCL
Stands for Hardware Compatibility List.
HDLC
High-Level Data Link Control. A standard protocol developed by the International Standards Organization
(ISO) for software applications and communicating devices operating in synchronous environments.
Defines operations at the link level of communications; for example, the format of data frames exchanged
between modems over a phone line.
HDMi
Stands for High Definition Media Interface, a type of video connection and display format.
Head
A small electromagnetic device inside a drive that reads, records, and erases data on the media.
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Head actuator
The device that moves read/write heads across a disk drive's platters. Most drives use a stepper-motor or
a voice-coil actuator. See drive and head.
Head crash
A (usually) rare occurrence in which a read/write head strikes a platter surface with sufficient force to
damage the magnetic medium.
Head parking
A procedure in which a disk drive's read/write heads are moved to an unused track so that they will not
damage data in the event of a head crash or other failure. See drive and head.
Head seek
The movement of a drive's read/write heads to a particular track. See also drive and head.
Heat sink
A mass of metal attached to a chip carrier or socket for the purpose of dissipating heat.
Helical scan
A type of recording technology that has vastly increased the capacity of tape drives. Invented for use in
broadcast systems and now used in VCRs. Conventional longitudinal recording records a track of data
straight across the width of a single-track tape. Helical scan recording packs more data on the tape by
positioning the tape at an angle to the recording heads. The heads spin to record diagonal stripes of
information on the tape.
Hexadecimal number
A number encoded in base-16, such that digits include the letters A through F as well as the numerals 0
through 9 (for example, 8BF3, which equals 35,827 in base-10).
Hidden file
A file that is not displayed in DOS directory listings because the file's attribute byte holds a special setting.
High density (HD)
An indication of the storage capacity of a floppy drive or disk in which 15 or 18 sectors per track are
recorded using MFM encoding.
High-level formatting
Formatting performed by the DOS FORMAT.COM program. Among other things, it creates the root
directory and file allocation tables. See also file allocation table.
History file
A file created by utility software to keep track of earlier use of the software. Many backup programs, for
example, keep history files describing earlier backup sessions. The program you are using now has a
history file that allows you to "back up" to previous topics.
HMA
An acronym for High Memory Area, the first 64K of extended memory which is controlled typically by the
HIMEM.SYS device driver. Real mode programs can be loaded into the HMA to conserve conventional
memory. Normally DOS 5.0 and higher use the HMA exclusively to reduce the DOS conventional
memory footprint.
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HPFS
Stands for High Performance File System, used with the OS/2 operating system by IBM.
HPT
High-pressure tin. A PLCC socket that promotes high forces between socket contacts and PLCC
contacts for a good connection.
HST
High-speed technology. The USRobotics proprietary high-speed modem-signaling scheme, developed
as an interim protocol until the V.32 protocol could be implemented in a cost-effective manner.
Incorporates trellis-coded modulation for greater immunity from variable phone-line conditions, and
asymmetrical modulation for more efficient use of the phone channel at speeds of 4800 bps and above.
The forward channel transmits at either 9600 bps (older designs) or 14400 bps, and the reverse channel
transmits at 450 bps. This technique eliminated the need for the V.32 echo-cancellation hardware that
was more costly at the time HST was developed. HST also incorporates MNP-compatible error-control
procedures adapted to the asymmetrical modulation.
HTML
Stands for Hyper-Text Markup Language, which browsers use to display data on websites.
HTPC
Stands for Home Theater Personal Computer.
HTTP
Stands for Hyper-Text Transfer Protocol, which allows for embedded links to other web locations within a
document.
HTTPS
Stands for Hyper-Text Transfer Protocol Secure, which uses encryption when data is passed over the
Internet between websites.
Hz
A mnemonic for hertz, a frequency measurement unit used internationally to indicate one cycle per
second.
I/O
Input/output. A circuit path that enables independent communications between the processor and
external devices.
IBMBIO.COM
One of the IBM DOS system files required to boot the machine. The first file loaded from disk during the
boot. Contains extensions to the ROM BIOS. Called IO.SYS for Microsoft operating systems.
IBMDOS.COM
One of the IBM DOS system files required to boot the machine. Contains the primary DOS routines.
Loaded by IBMBIO.COM, it in turns loads COMMAND.COM. Called MSDOS.SYS for Microsoft operating
systems.
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IC
An acronym for integrated circuit, a complete electronic circuit contained on a single chip. May consist of
only a few transistors, capacitors, diodes, or resistors, or thousands of them, and generally is classified
according to the complexity of the circuitry and the approximate number of circuits on the chip. SSI
(small-scale integration) equals 2 to 10 circuits. MSI (medium-scale integration) equals 10 to 100 circuits.
LSI (large-scale integration) equals 100 to 1,000 circuits. VLSI (very-large-scale integration) equals 1,000
to 10,000 circuits. ULSI (ultra-large-scale integration) equals more than 10,000 circuits.
ICMP
Stands for Internet Control Message Protocol.
ICR
Stands for Intelligent Character Recognition, used when scanning paper documents.
IDE
An acronym for integrated drive electronics. Describes a hard disk with the disk controller circuitry
integrated within it. The first IDE drives commonly were called hard cards. Also refers to the ATA interface
standard, the standard for attaching hard disk drives to ISA bus IBM-compatible computers. IDE drives
typically operate as though they were standard ST-506/412 drives. See also ATA.
IDS
Stands for Intrusion Detection System.
IEEE
Stands for the Institute of Electrical and Electronics Engineers.
IIS
Stands for Internet Information Services, Microsoft’s method for supporting content on the Web.
IMAP
Stands for Internet Mail Access Protocol
IMEI
Stands for International Mobile Equipment Identity, used with cellular devices.
IMSI
Stands for International Mobile Subscriber Identity, an identifier used with cellular services providers.
Incremental backup
A backup of all files that have changed since the last backup.
Infrared or IR
Infrared or IR devices use the IR electromagnetic spectrum for wireless communications, such as are
found in television remote controls, or “presentation clickers” used with PCs and laptops.
Initiator
A device attached to the SCSI bus that sends a command to another device (the target) on the SCSI bus.
The SCSI host adapter plugged into the system bus is an example of an SCSI initiator.
Inkjet printer
A type of printer that sprays one or more colors of ink on the paper. Can produce output with quality
approaching that of a laser printer at a lower cost.
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Input
Data sent to the computer from the keyboard, the telephone, the video camera, another computer,
paddles, joysticks, and so on.
Instruction
Program step that tells the computer what to do for a single operation.
Interface
A communications device or protocol that enables one device to communicate with another. Matches the
output of one device to the input of the other device.
Interlacing
Interlacing is a method of scanning alternate lines of pixels on a display screen. The odd lines are
scanned first from top to bottom and left to right. The electron gun goes back to the top and makes a
second pass scanning the even lines. Interlacing requires two scan passes to construct a single image.
Because of this additional scanning, interlaced screens are often seen to flicker unless a long persistence
phosphor is used in the display.
Interleave ratio
The number of sectors that pass beneath the read/write heads before the next numbered sector arrives.
When the interleave ratio is 3:1, for example, a sector is read, two pass by, and then the next is read. A
proper interleave ratio, laid down during low-level formatting, enables the disk to transfer information
without excessive revolutions due to missed sectors. See sector and head.
Internal command
In DOS, a command contained in COMMAND.COM so that no other file must be loaded in order to
perform the command. DIR and COPY are two examples of internal commands.
Internal drive
A disk or tape drive mounted inside one of a computer's disk drive bays (or a hard disk card, which is
installed in one of the computer's slots).
Interpreter
A translator program for a high-level language that translates and executes the program at the same
time. The program statements that are interpreted remain in their original source language, the way the
programmer wrote them; that is, the program does not need to be compiled before execution. Interpreted
programs run slower than compiled programs and must be run with the interpreter loaded in memory.
Interrupt
A suspension of a process, such as the execution of a computer program, caused by an event external to
that process and performed in such a way that the process can be resumed. An interrupt can be caused
by internal or external conditions such as a signal indicating that a device or program has completed a
transfer of data.
Interrupt vector
A pointer in a table that gives the location of a set of instructions that the computer should execute when
a particular interrupt occurs.
IO.SYS
One of the MS-DOS system files required to boot the machine. The first file loaded from disk during the
boot. Contains extensions to the ROM BIOS. Called IBMBIO.COM in IBM operating systems.
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IP
Stands for Internet Protocol
IPCONFIG
A command-line request that will display a host’s IP configuration data.
IPP
Stands for Internet Printing Protocol
IPS (or IDS)
Stands for Intrusion Protection System, which typically is integrated into an Internet appliance as a part
of a Unified Threat Management (UTM) system. IDS stands for Intrusion Detection System.
Also can stand for In-Plane Switching, a screen display technology for LCD screens.
IPSEC
Stands for Internet Protocol Security.
IR
Stands for Infrared (or infra-red).
IRDA
Stands for the Infrared Data Association, an industry standards-setting group.
IRP
Stands for Incident Response Plan.
IRQ
An acronym for interrupt request. Physical connections between external hardware devices and the
interrupt controllers. When a device such as a floppy controller or a printer needs the attention of the
CPU, an IRQ line is used to get the attention of the system to perform a task. On PC and XT
IBM-compatible systems, 8 IRQ lines are included, numbered IRQ0 through IRQ7. On the AT and PS/2
systems, 16 IRQ lines are numbered IRQ0 through IRQ15. IRQ lines must be used by only a single
adapter in the ISA bus systems, but Micro Channel Architecture (MCA) adapters can share interrupts.
ISDN
An acronym for Integrated Services Digital Network, an international telecommunications standard that
enables a communications channel to carry digital data simultaneously with voice and video information.
ISO
An acronym for International Standards Organization. The ISO, based in Paris, develops standards for
international and national data communications. The U.S. representative to the ISO is the American
National Standards Institute (ANSI).
ISO 9660
ISO 9660 is an international standard that defines file systems for CD-ROM disks, independent of the
operating system. ISO (International Standards Organization) 9660 has two levels. Level one provides
for DOS file system compatibility, while Level two allows file names of up to 32 characters.
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ISP
Short for Internet Service Provider, a company that provides access to the Internet. For a monthly fee, the
service provider gives you a software package, username, password and access phone number.
Equipped with a modem and telephone line or a network card and broadband connection, you can then
log on to the Internet and browse the World Wide Web and USENET, and send and receive e-mail.
In addition to serving individuals, ISPs also serve large companies, providing a direct connection from the
company's networks to the Internet. ISPs themselves are connected to one another through Network
Access Points (NAPs).
ISPs are also called IAPs (Internet Access Providers).
J-lead
J-shaped leads on chip carriers. Can be surface-mounted on a PC board or plugged into a socket that
then is mounted on a PC board, usually on .050-inch centers.
JEDEC
Joint Electron Devices Engineering Council. A group that establishes standards for the electronics
industry.
JPEG or JPG
JPEG is an acronym for the Joint Photographic Experts Group, a lossy data compression standard that
was originally designed for still images, but can also compress real-time video (30 frames per second)
and animation. Lossy compression permanently discards unnecessary data, resulting in some loss of
precision.
Jumper
A small, plastic-covered, metal clip that slips over two pins protruding from a circuit board. Sometimes
also called a shunt. When in place, the jumper connects the pins electrically and closes the circuit. By
doing so, it connects the two terminals of a switch, turning it on.
Kermit
A protocol designed for transferring files between microcomputers and mainframes. Developed by Frank
DaCruz and Bill Catchings, at Columbia University (and named after the talking frog on The Muppet
Show). Widely accepted in the academic world. The complete Kermit protocol manual and the source for
various versions is available from Kermit Distribution, Columbia University Center for Computing
Activities, 612 West 115 Street, New York, NY 10025, (212) 854-3703.
Key disk
In software copy protection, a distribution floppy disk that must be present in a floppy disk drive for an
application program to run.
Keyboard macro
A series of keystrokes automatically input when a single key is pressed.
Kilo
A multiplier indicating one thousand (1,000) of some unit. Abbreviated as k or K. When used to indicate a
number of bytes of memory storage, the multiplier definition changes to 1,024. One kilobit, for example,
equals 1,000 bits, and one kilobyte equals 1,024 bytes.
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Kilobyte (KB)
A unit of information storage equal to 1,024 bytes. A kilobit (Kb) is 1024 bits, not bytes.
KVM switch box
A keyboard-video-mouse (KVM) switch box allows you to connect several computers to one keyboard,
monitor and mouse.
LAN
Stands for Local Area Network.
Landing zone
An unused track on a disk surface on which the read/write heads can land when power is shut off. The
place that a parking program or a drive with an autopark mechanism parks the heads. See also head.
LAPM
Link-access procedure for modems, an error-control protocol incorporated in CCITT Recommendation
V.42. Like the MNP and HST protocols, uses cyclic redundancy checking (CRC) and retransmission of
corrupted data (ARQ) to ensure data reliability.
Laptop computer
A computer system smaller than a briefcase but larger than a notebook, and that usually has a clamshell
design in which the keyboard and display are on separate halves of the system, which are hinged
together. These systems normally run on battery power.
Laser printer
A type of printer that is a combination of an electrostatic copying machine and a computer printer. The
output data from the computer is converted by an interface into a raster feed, similar to the impulses that
a TV picture tube receives. The impulses cause the laser beam to scan a small drum that carries a
positive electrical charge. Where the laser hits, the drum is discharged. A toner, which also carries a
positive charge, then is applied to the drum. This toner, a fine black powder, sticks only to the areas of the
drum that have been discharged electrically. As it rotates, the drum deposits the toner on a negatively
charged sheet of paper. Another roller then heats and bonds the toner to the page.
Latency
The amount of time required for a disk drive to rotate half of a revolution. Represents the average amount
of time to locate a specific sector after the heads have arrived at a specific track. Latency is part of the
average access time for a drive.
LBA
Stands for Logical Block Addressing, a method of getting the BIOS to recognize hard disks having
greater than 1,024 cylinders, which is an addressing limit in IBM-class PCs.
LC
Stands for Lucent Connector, a type of fiber-optic cable connector.
LCC
Leadless chip carrier. A type of integrated circuit package that has input and output pads rather than
leads on its perimeter.
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LCD
An acronym for liquid crystal display, a display that uses liquid crystal sealed between two pieces of
polarized glass. The polarity of the liquid crystal is changed by an electric current to vary the amount of
light that can pass through. Because LCD displays do not generate light, they depend on either the
reflection of ambient light or backlighting the screen. The best type of LCD, the active-matrix or thin-film
transistor (TFT) LCD, offers fast screen updates and true color capability.
LDAP
Stands for Lightweight Directory Address Protocol, used by email and directory systems on networks
and the Internet.
LED
An acronym for light-emitting diode, a semiconductor diode that emits light when a current is passed
through it.
LIF
Low insertion force. A type of socket that requires only a minimum of force to insert a chip carrier.
Light pen
A hand-held input device with a light-sensitive probe or stylus, connected to the computer's graphics
adapter board by a cable. Used for writing or sketching on-screen or as a pointing device tool for making
selections. Unlike mice, not widely supported by software applications.
Li-on
Stands for Lithium-Ion, a type of battery used in laptops and other devices.
Local echo
A modem feature that enables the modem to send copies of keyboard commands and transmitted data to
the screen. When the modem is in command mode (not on-line to another system), the local echo
normally is invoked through an ATE1 command, which causes the modem to display your typed
commands. When the modem is on-line to another system, the local echo is invoked by an ATF0
command, which causes the modem to display the data it transmits to the remote system.
Logical drive
A drive as named by a DOS drive specifier, such as C: or D:. Under DOS 3.3 or later, a single physical
drive can act as several logical drives, each with its own specifier.
Loopback address
A loopback address is a special IP number (127.0.0.1) that is designated for the software loopback
interface of a machine. The loopback interface has no hardware associated with it, and it is not physically
connected to a network.
The loopback interface allows IT professionals to test IP software without worrying about broken or
corrupted drivers or hardware.
Lost clusters
Clusters that have been marked accidentally as unavailable in the file allocation table even though they
belong to no file listed in a directory.
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Low-level formatting
Formatting that divides tracks into sectors on the platter surfaces. Places sector-identifying information
before and after each sector and fills each sector with null data (usually hex F6). Specifies the sector
interleave and marks defective tracks by placing invalid checksum figures in each sector on a defective
track. See formatting.
LPD
Stands for Line Printer Daemon.
LPR
Stands for Line Printer Remote. Similar to Line Printer Daemon.
LPT
Stands for Line Printer Terminal, a synonym for a parallel port.
LUN
An acronym for logical unit number, a number given to a device (a logical unit) attached to a SCSI
physical unit and not directly to the SCSI bus. Although as many as eight logical units can be attached to
a single physical unit, normally a single logical unit is a built-in part of a single physical unit. A SCSI hard
disk, for example, has a built-in SCSI bus adapter that is assigned a physical unit number or SCSI ID, and
the controller and drive portions of the hard disk are assigned a logical unit number (usually 0).
LVD
Stands for Low Voltage Differential, a type of SCSI hard disk interface.
MAC
Stands for Media Access Control, an identification number unique to all network interface cards.
Magnetic domain
A tiny segment of a track just large enough to hold one of the magnetic flux reversals that encode data on
a disk surface.
Magneto-optical recording
An erasable optical disk recording technique that uses a laser beam to heat pits on the disk surface to the
point at which a magnet can make flux changes.
Malware
Short for malicious software, software designed specifically to damage or disrupt a system, such as a
virus or a Trojan horse.
MAPI
Stands for Messaging Application Programming Interface.
Master partition boot sector
On hard disks, a one-sector record that gives essential information about the disk and tells the starting
locations of the various partitions. Always the first physical sector of the disk.
MAU
Stands for Media Access Unit or Media Attachment Unit.
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MB
Stands for Megabyte, which is a storage capacity of 1,048,576 bytes. A megabit (Mb) by comparison is
equal to 1,048,576 bits, not bytes.
MBR
Stands for Master Boot Record, which is a component of a disk partition table.
MBSA
Stands for Microsoft Baseline Security Analyzer.
MCA
An acronym for Micro Channel Architecture. Developed by IBM for the PS/2 line of computers and
introduced on April 2, 1987. Features include a 16- or 32-bit bus width and multiple master
control. By allowing several processors to arbitrate for resources on a single bus, the MCA is optimized
for multitasking, multiprocessor systems. Offers switchless configuration of adapters, which eliminates
one of the biggest headaches of installing older adapters.
MCGA
An acronym for MultiColor Graphics Array, a type of PC video display circuit introduced by IBM on April 2,
1987, that supports text and graphics. Text is supported at a maximum resolution of 80x25 characters in
16 colors with a character box of 8x16 pixels. Graphics is supported at a maximum resolution of 320x200
pixels in 256 (from a palette of 262,144) colors or 640x480 pixels in 2 colors. The MCGA outputs an
analog signal with a horizontal scanning frequency of 31.5 KHz, and supports analog color or analog
monochrome displays.
MCI
MCI is an acronym that stands for Media Control Interface, a device-independent specification for
controlling multimedia devices and files. MCI is a part of the multimedia extensions and offers a standard
interface set of device control commands, making it easy to program multimedia applications. MCI
commands are used for audio recording and playback and animation playback. Videodisk players and
other optional devices are controlled by MCI. Device types include CD audio, digital audio tape players,
scanners, MIDI sequencers, videotape players or recorder and audio devices that play digitized
waveform files. MCI classifies compound and simple device drivers. Compound drivers require a device
element (usually a file and a path) during operation. Simple devices do not require a device element for
playback.
MDA
An acronym for Monochrome Display Adapter, a type of PC video display adapter introduced by IBM on
August 12, 1981, that supports text only. Text is supported at a maximum resolution of 80x25 characters
in four colors with a character box of 9x14 pixels. Colors, in this case, indicates black, white, bright white,
and underlined. Graphics modes are not supported. The MDA outputs a digital signal with a horizontal
scanning frequency of 18.432 KHz, and supports TTL monochrome displays. The IBM MDA also
included a parallel printer port.
Medium
The magnetic coating or plating that covers a disk or tape.
Mega
A multiplier indicating 1 million (1,000,000) of some unit. Abbreviated as m or M. When used to indicate a
number of bytes of memory storage, the multiplier definition changes to 1,048,576. One megabit, for
example, equals 1,000,000 bits, and one megabyte equals 1,048,576 bytes.
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Megabyte
A unit of information storage equal to 1,048,576 bytes. A megabit (Mb) is by comparison equal to
1,048,576 bits, not bytes.
Memory
Any component in a computer system that stores information for future use.
Memory caching
A service provided by extremely fast memory chips that keeps copies of the most recent memory
accesses. When the CPU makes a subsequent access, the value is supplied by the fast memory
rather than by relatively slow system memory.
Memory-resident program
A program that remains in memory after it has been loaded, consuming memory that otherwise might be
used by application software.
Menu software
Utility software that makes a computer easier to use by replacing DOS commands with a series of menu
selections.
MFD
Stands for a Multi-Function Device, such as an all-in-one printer.
MFM
Modified Frequency Modulation encoding. A method of encoding data on the surface of a disk. The
coding of a bit of data varies by the coding of the preceding bit to preserve clocking information.
MFP
Stands for a Multi-Function printer, such as an all-in-one printer.
MHz
An abbreviation for megahertz, a unit of measurement for indicating the frequency of one million cycles
per second. One hertz (Hz) is equal to one cycle per second. Named after Heinrich R. Hertz, a German
physicist who first detected electromagnetic waves in 1883.
MI/MIC
Mode Indicate/Mode Indicate Common, also called forced or manual originate. Provided for installations
in which equipment other than the modem does the dialing. In such installations, the modem operates in
dumb mode (no auto-dial capability) yet must go off-hook in originate mode to connect with answering
modems.
Micro
A prefix indicating one millionth (1/1,000,000 or .000001) of some unit. Abbreviated as u.
MicroDIMM
Stands for a Micro Dual In-line Memory Module, a type of memory stick.
Microprocessor
A solid-state central processing unit much like a computer on a chip. An integrated circuit that accepts
coded instructions for execution.
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Microsecond
A unit of time equal to one millionth (1/1,000,000 or .000001) of a second. Abbreviated as us.
MIDI
An acronym for Musical Instrument Digital Interface, an interface and file format standard for connecting a
musical instrument to a microcomputer and storing musical instrument data. Multiple musical instruments
can be daisy-chained and played simultaneously with the help of the computer and related software. The
various operations of the instruments can be captured, saved, edited, and played back. A MIDI file
contains note information, timing (how long a note is held), volume and instrument type for as many as 16
channels. Sequencer programs are used to control MIDI functions such as recording, playback and
editing. MIDI files store only note instructions and not actual sound data.
Milli
A prefix indicating one thousandth (1/1,000 or .001) of some unit. Abbreviated as m.
Millisecond
A unit of time equal to one thousandth (1/1,000 or .001) of a second. Abbreviated as ms.
MIME
Stands for Multi-purpose Internet Mail Extension, which is a standard for formatting files of different types,
such as text, graphics, or audio, so they can be sent over the Internet and seen or played by a web
browser or e-mail application.
MIMO
Stands for Multiple Input Multiple Output.
MIPS
An acronym for million instructions per second. Refers to the average number of machine-language
instructions a computer can perform or execute in one second. Because different processors can perform
different functions in a single instruction, MIPS should be used only as a general measure of performance
among different types of computers.
MMC
Stands for Microsoft Management Console.
Mnemonic
A mnemonic is an abbreviated name for something, which is used in a manner similar to an acronym.
Computer processor instructions are often abbreviated with a mnemonic such as JMP (Jump), CLR
(Clear), STO (Store), INIT (Initialize). A mnemonic name for an instruction or an operation makes it easy
to remember and convenient to use.
MNP
Microcom Networking Protocol. Asynchronous error-control and data-compression protocols developed
by Microcom, Inc. and now in the public domain. Ensure error-free transmission through error detection
(CRC) and retransmission of errored frames. MNP Levels 1 through 4 cover error control and have been
incorporated into CCITT Recommendation V.42. MNP Level 5 includes data compression but is eclipsed
in superiority by V.42bis, an international standard that is more efficient. Most high-speed modems will
connect with MNP Level 5 if V.42bis is unavailable.
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MO
MO is an acronym for Magneto Optical. MO drives utilize both magnetic and optical storage properties.
MO technology is erasable and recordable, as opposed to CD-ROM (Read Only) and WORM (Write
Once) drives. MO uses laser and magnetic field technology to record and erase data. The laser is used to
heat an area on the disk which can then be recorded magnetically. MO drives are most commonly used in
removable storage applications.
Modem
Modulator-demodulator. A device that converts electrical signals from a computer into an audio form
transmittable over telephone lines, or vice versa. Modulates, or transforms, digital signals from a
computer into the analog form that can be carried successfully on a phone line; also demodulates signals
received from the phone line back to digital signals before passing them to the receiving computer.
Module
An assembly that contains a complete circuit or sub-circuit.
Morphing
Morphing is a pseudo slang term for metamorphosis, the transformation of one object into another.
Morphing is performed by software that analyzes an two images and creates several in-between images
such that one image appears to become the other. Originally requiring expensive, high powered
computer hardware, morphing can now be done on PC systems with sophisticated software now
available.
MOS
An acronym for Metal-Oxide Semiconductor. Refers to the three layers used in forming the gate structure
of a field-effect transistor (FET). MOS circuits offer low power dissipation and enable transistors to be
jammed close together before a critical heat problem arises. PMOS, the oldest type of MOS circuit, is a
silicon-gate P-channel MOS process that uses currents made up of positive charges. NMOS is a
silicon-gate N-channel MOS process that uses currents made up of negative charges and is at least twice
as fast as PMOS. CMOS, Complementary MOS, is nearly immune to noise, runs off almost any power
supply, and is an extremely low-power circuit technique.
Motherboard
The main circuit board in the computer. Also called planar, system board, or backplane.
MP3 / MP4
Stands for Moving Picture Experts Group Layer 3 Audio (or Layer 4 Audio).
MPEG
MPEG is an acronym for the Moving Pictures Experts Group, a lossy data compression standard for
motion-video and audio. Lossy compression permanently discards unnecessary data, resulting in some
loss of precision. MPEG compression produces about a 50% volume reduction in file size.
MSCONFIG
A Microsoft application that allows the user to configure or change various aspects of the system bootup sequence.
MSDOS.SYS
One of the MS-DOS system files required to boot the machine. Contains the primary DOS routines.
Loaded by IO.SYS, it in turns loads COMMAND.COM. Called IBMCOM.COM in IBM operating systems.
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MSDS
Stands for Material Safety Data Sheet, which is promoted by the Occupational Safety and Health
Administration (OSHA).
MTBF
An acronym for mean time between failure, a statistically derived measure of the probable time a device
will continue to operate before a hardware failure occurs, usually given in hours. Because no standard
technique exists for measuring MTBF, a device from one manufacturer can be significantly more or
significantly less reliable than a device with the same MTBF rating from another manufacturer.
MTTR
An acronym for mean time to repair, a measure of the probable time it will take a technician to service or
repair a specific device, usually given in hours.
MUI
Stands for Multilingual User Interface.
Multimedia
Multimedia is the integration of sound, graphic images, animation, motion video and/or text in one
environment on a computer. It is a set of hardware and software technologies that are rapidly changing
and enhancing the computing environment.
Multitask
Run several programs simultaneously.
Multiuser system
A system in which several computer terminals share the same central processing unit (CPU).
Nano
A prefix indicating one billionth (1/1,000,000,000 or .000000001) of some unit. Abbreviated as n.
Nanosecond
A unit of time equal to one billionth (1/1,000,000,000 or .000000001) of a second. Abbreviated as ns.
NAC
Stands for Network Access Control.
NAS
Stands for Network-Attached Storage.
NAT
Short for Network Address Translation, an Internet standard that enables a local-area network (LAN) to
use one set of IP addresses for internal traffic and a second set of addresses for external traffic. A NAT
box located where the LAN meets the Internet makes all necessary IP address translations.
NAT serves three main purposes:
●
●
●
Provides a type of firewall by hiding internal IP addresses
Enables a company to use more internal IP addresses. Since they're used internally only, there's
no possibility of conflict with IP addresses used by other companies and organizations.
Allows a company to combine multiple ISDN connections into a single Internet connection.
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Near Field Communications (NFC) devices
Near field communication (NFC) is a set of communication protocols that enable two electronic devices,
one of which is usually a portable device such as a smartphone, to establish communication by bringing
them within 10 cm (4 in) of each other.
Similar ideas in advertising and industrial applications were not generally successful commercially,
outpaced by technologies such as barcodes and UHF RFID tags. NFC protocols established a generallysupported standard. When one of the connected devices has Internet connectivity, the other can
exchange data with online services. NFC-enabled portable devices can be provided with apps, for
example to read electronic tags or make payments when connected to an NFC-compliant apparatus.
Earlier close-range communication used technology that was proprietary to the manufacturer, for
applications such as stock ticket, access control and payment readers.
Like other 'proximity card' technologies, NFC employs electromagnetic induction between two loop
antennae when NFC devices—for example a smartphone and a 'smartposter'—exchange information,
operating within the globally available unlicensed radio frequency ISM band of 13.56 MHz on ISO/IEC
18000-3 air interface at rates ranging from 106 to 424 kbit/s. NFC tags contain data and are typically
read-only, but may be writeable. They can be custom-encoded by their manufacturers or use NFC
Forum specifications. The tags can securely store personal data such as debit and credit card
information, loyalty program data, PINs and networking contacts, among other information. NFC devices
are full-duplex—they are able to receive and transmit data at the same time. Thus, they can check for
potential collisions if the received signal frequency does not match the transmitted signal's frequency.
Examples of ways that NFC devices can be used include smartphone payments at a retail establishment
using ApplePay or GooglePay, or using a “SmartTrip card” to pay for a subway fare.
NetBIOS
Stands for Networked Basic Input-Output System.
NETBEUI
Stands for Networked Basic Input-Output System Extended User Interface.
Network
A system in which a number of independent computers are linked in order to share data and peripherals,
such as hard disks and printers.
NFS
Stands for Network File System.
NIC
Stands for Network Interface Card.
Ni-CD
Stands for Nickel-Cadmium, a type of battery used in laptops and other devices.
NiMH
Stands for Nickel-Metal-Hydride, a type of battery used in laptops and other devices.
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NLX
Stands for New Low-profile eXtended, a type of motherboard and computer case form factor.
NNTP
Stands for Network News Transfer Protocol
NTFS
Stands for New Technology File System, the default filesystem type for current Windows operating
systems.
NTLDR
Stands for New technology Loader; the bootstrap loader program for Windows operating systems.
NTP
Stands for Network Time Protocol.
Nonvolatile memory (NVRAM)
Random-access memory whose data is retained when power is turned off. Sometimes nonvolatile RAM
is retained without any power whatsoever, as in EEPROM or flash memory devices. In other cases the
memory is maintained by a small battery. Nonvolatile RAM that is battery maintained is sometimes also
called CMOS memory. CMOS NVRAM is used in IBM-compatible systems to store configuration
information. True NVRAM often is used in intelligent modems to store a user-defined default
configuration loaded into normal modem RAM at power-up.
Nonvolatile RAM disk
A RAM disk powered by a battery supply so that it continues to hold its data during a power outage.
NTSC
An acronym for the National Television Standards Committee, which governs the standard for television
and video playback and recording in the United States. The NTSC was originally organized in 1941 when
TV broadcasting first began on a wide scale. The original standard they created was called RS-170A,
which is now simply referred to as NTSC. The NTSC standard provides for 525 scan lines of resolution
and is transmitted at 60 half-frames per second. It is an interlaced signal, which means that it scans every
other line each time the screen is refreshed. The signal is generated as a composite of red, green, and
blue signals for color and includes an FM frequency for audio and a signal for stereo. Twenty years later,
higher standards were adopted in Europe with the PAL and SECAM systems, both incompatible with the
NTSC standard of North America. NTSC is also called composite video.
Null modem
A serial cable wired so that two data terminal equipment (DTE) devices, such as personal computers, or
two data communication equipment (DCE) devices, such as modems or mice, can be connected. Also
sometimes called a modem-eliminator. To make a null-modem cable with DB-25 connectors, you wire
these pins together: 1-1, 2-3, 3-2, 4-5, 5-4, 6-20, 20-6, and 7-7.
Object hierarchy
Object hierarchy occurs in a graphical program when two or more objects are linked and one object's
movement is dependent on the other object. This is known as a parent-child hierarchy. In an example
using a human figure, the fingers would be child objects to the hand, which is a child object to the arm,
which is a child to the shoulder and so on. Object hierarchy provides much control for an animator in
moving complex figures.
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OCR
An acronym for optical character recognition, an information-processing technology that converts
human-readable text into computer data. Usually a scanner is used to read the text on a page, and OCR
software converts the images to characters.
OEM
An acronym for original equipment manufacturer, any manufacturer that sells its product to a reseller.
Usually refers to the original manufacturer of a particular device or component. Most COMPAQ hard
disks, for example, are made by Conner Peripherals, who is considered the OEM.
OLE
An acronym for Object Linking and Embedding, an enhancement to the original Dynamic Data Exchange
(DDE) protocol that allows you to embed or link data created in one application in a document created in
another application, and subsequently edit that data directly from the final document.
OLED
Stands for Organic Light-Emitting Diode, used in newer LED monitors.
OS
Stands for Operating System.
On-line fallback
A feature that enables high-speed error-control modems to monitor line quality and fall back to the next
lower speed if line quality degrades. The modems fall forward as line quality improves.
Operating system (or OS)
A collection of programs for operating the computer. Operating systems perform housekeeping tasks
such as input and output between the computer and peripherals and accepting and interpreting
information from the keyboard. DOS and OS/2 are examples of popular operating systems.
Optical disk
A disk that encodes data as a series of reflective pits that are read (and sometimes written) by a laser
beam.
Orange Book
Orange Book is the standard for recordable compact disks (like CD-ROM, but recordable instead of Read
Only). Recordable compact disks are called CD-R and are becoming popular with the widespread use of
multimedia. Publishers use CD-R when transferring paper books to electronic publishing tools. Part of the
Orange Book standard defines rewritable Magneto Optical disks and another section defines optical
Write Once Read Many (WORM) disks. Publishers usually record a master onto a CD-R WORM disk
prior to mass distribution. Titles recorded on WORM can be played by any standard CD-ROM drive
(Yellow Book).
Originate mode
A state in which the modem transmits at the predefined low frequency of the communications channel
and receives at the high frequency. The transmit/receive frequencies are the reverse of the called
modem, which is in answer mode.
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OS/2
A universal operating system developed through a joint effort by IBM and Microsoft Corporation. OS/2
was intended as the successor to DOS (developed also by Microsoft and IBM) and Windows. OS/2 uses
the protected mode operation of the processor to expand memory from 1M to 16M and to support fast,
efficient multitasking. The OS/2 Presentation Manager, an integral part of the system, is a graphical
interface similar to Microsoft Windows and the Apple Macintosh system. The latest version runs DOS,
Windows, and OS/2-specific software.
Output
Information processed by the computer; or the act of sending that information to a mass storage device
such as a video display, a printer, or a modem.
Overlay
Part of a program that is loaded into memory only when it is required.
Overrun
A situation in which data moves from one device faster than a second device can accept it.
Overwrite
To write data on top of existing data, thus erasing the existing data.
Package
A device that includes a chip mounted on a carrier and sealed.
PAL
An acronym for phase alternating line system. Invented in 1961 and refers to a system of TV
broadcasting used in England and other European countries. With its 625-line picture delivered at 25
frames/second, PAL provides a better image and an improved color transmission over the NTSC
system used in North America. PAL also can stand for Programmable Array Logic, a type of chip that has
logic gates specified by a device programmer.
Palmtop computer
A computer system smaller than a notebook that is designed so that it can be held in one hand while
being operated by the other.
Parallel
A method of transferring data characters in which the bits travel down parallel electrical paths
simultaneously; for example, eight paths for eight-bit characters. Data is stored in computers in
parallel form but may be converted to serial form for certain operations.
PAN
Stands for Personal Area Network.
Parity
A method of error checking in which an extra bit is sent to the receiving device to indicate whether an
even or odd number of binary 1 bits were transmitted. The receiving unit compares the received
information with this bit and can obtain a reasonable judgment about the validity of the character. The
same type of parity (even or odd) must be used by two communicating computers, or both may omit
parity. When parity is used, a parity bit is added to each transmitted character. The bit's value is 0 or 1, to
make the total number of 1s in the character even or odd, depending on which type of parity is used.
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Park program
A program that executes a seek to the highest cylinder or just past the highest cylinder of a drive so that
the potential of data loss is minimized if the drive is moved. See head parking.
Partition
A section of a hard disk devoted to a particular operating system. Most hard disks have only one partition,
devoted to DOS. A hard disk can have as many as four partitions, each occupied by a different operating
system. DOS V3.3 or higher can occupy two of these four partitions.
Pascal
A high-level programming language named for the French mathematician Blaise Pascal (1623-1662).
Developed in the early 1970s by Niklaus Wirth for teaching programming and designed to support the
concepts of structured programming. Easy to learn and often the first language taught in schools.
PATA
Stands for Parallel Advanced Technology Attachment; synonym for IDE/EIDE and ATAPI.
PC
Stands for Personal Computer.
PCI
Stands for Peripheral Component Interconnect, a type of bus connection on a motherboard.
PCIe
Stands for Peripheral Component Interconnect Express, a type of bus connection on a motherboard.
PCI-X
Stands for Peripheral Component Interconnect eXtended, a type of bus connection on a motherboard.
PCL
Stands for Printer Control Language, used between computers and laser printers.
PCMCIA
Stands for Personal Computer Memory Card International Association, a standard for cards that attach
to laptops and PCs.
PE
Stands for Pre-installation Environment.
Pentium
A series of CPUs built by Intel; now being produced at under a million units per year. Intel began highcapacity production in late 1995. The 60+-Mhz Pentium was the first true 64-bit system.
Peripheral
Any piece of equipment used in computer systems that is an attachment to the computer. Disk drives,
terminals, and printers are all examples of peripherals.
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PGA (and PGA2)
Pin-grid array. A chip package that has a large number of pins on the bottom designed for socket
mounting. Also can mean Professional Graphics Adapter, a limited-production, high-resolution graphics
card for XT and AT systems from IBM.
Photo CD
Photo CD is a technology developed by Eastman Kodak and Philips that provides for storing
photographic images from 35mm film on a CD-R recordable compact disk. Images stored on the Photo
CD may have resolutions as high as 2,048 x 3,072 pixels. Up to 100 true-color images (24-bit color) can
be stored on one disk. Photo CD images are created by scanning 35mm film and digitally recording the
images on compact disks (CDs). The digitized images are indexed (given a 4-digit code) and thumbnails
of each image on the disk are shown on the front of the case along with its index number. Multi-session
capability allows several rolls of 35mm film to be added to a single disk on different occasions.
Physical drive
A single disk drive. DOS defines logical drives, which are given a specifier, such as C: or D:. A single
physical drive may be divided into multiple logical drives. Conversely, special software can span a single
logical drive across two physical drives.
PIF
An acronym for Program Information File, a file that contains information about a non-Windows
application specifying optimum settings for running the program under Windows.
PII
Stands for Personally-Identifiable Information.
PIN
Stands for Personal Identification Number.
Pixel
A mnemonic term meaning picture element. Any of the tiny elements that form a picture on a video
display screen. Also called a pel.
PKI
Stands for Public Key Infrastructure, used in encryption of data and files.
Planar board
A term equivalent to motherboard, used by IBM in some of its literature.
Plated media
Hard disk platters plated with a form of thin metal film media on which data is recorded.
Platter
A disk contained in a hard disk drive. Most drives have two or more platters, each with data recorded on
both sides.
PLCC
Plastic leaded-chip carrier. A popular chip-carrier package with J-leads around the perimeter of the
package. See J-lead.
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PnP
Stands for Plug-and-Play.
POP3
Stands for Post Office Protocol 3, used in sending email via the Internet.
Port
Plug or socket that enables an external device such as a printer to be attached to the adapter card in the
computer. Also a logical address used by a microprocessor for communications between itself and
various devices.
Port address
One of a system of addresses used by the computer to access devices such as disk drives or printer
ports. You may need to specify an unused port address when installing any adapter boards
in a system unit.
Portable computer
A computer system smaller than a transportable system, but larger than a laptop system. Most portable
systems conform to the lunchbox style popularized by COMPAQ, or the briefcase style popularized by
IBM, each with a fold-down (removable) keyboard and built-in display. These systems characteristically
run on AC power and not on batteries, include several expansion slots, and can be as powerful as
full-blown desktop systems.
POS
An acronym for Programmable Option Select. The Micro Channel Architecture's POS eliminates switches
and jumpers from the system board and adapters by replacing them with programmable registers.
Automatic configuration routines store the POS data in a battery-powered CMOS memory for system
configuration and operations. The configuration utilities rely on adapter description (ADF) files that
contain the setup data for each card. See MCA.
Also stands for Point-of-Sale.
POST
Power-On Self-Test. A series of tests run by the computer at power-on. Most computers scan and test
many of their circuits and sound a beep from the internal speaker if this initial test indicates proper system
performance.
PostScript
A page-description language developed primarily by John Warnock, of Adobe Systems, for converting
and moving data to the laser-printed page. Instead of using the standard method of transmitting graphics
or character information to a printer, telling it where to place dots one-by-one on a page, PostScript
provides a way for the laser printer to interpret mathematically a full page of shapes and curves.
POTS
Stands for Plain-Old Telephone System; also called the Public Switched Telephone Network (PSTN).
Power supply
An electrical/electronic circuit that supplies all operating voltage and current to the computer system.
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PPP
Stands for Point-to-Point Protocol, used when connecting to the Internet.
PPTP
Stands for Point-to-Point Tunneling Protocol, which enables data security over the Internet.
Presentation Manager
The graphical, icon- and window-based software interface offered with IBM’s OS/2 operating system.
Primary partition
An ordinary, single-volume bootable partition. See also extended partition.
PRI
Stands for Primary Rate Interface.
Privacy filter
A piece of polarized semi-transparent plastic that obscures the view of the monitor when viewed at an
angle.
Processor speed
The clock rate at which a microprocessor processes data. The original IBM PC, for example, operates at
4.77 MHz (4.77 million cycles per second).
Program
A set of instructions or steps telling the computer how to handle a problem or task.
PROM
Programmable read-only memory. A type of memory chip that can be programmed to store information
permanently--information that cannot be erased.
Proprietary
Anything invented by a company and not used by any other company. Especially applies to cases in
which the inventing company goes to lengths to hide the specifications of the new invention. The opposite
of standard.
Protected mode
A mode available in all Intel 80286- or 80386-compatible processors. In this mode, memory addressing is
extended to 16 or 4096 megabytes, and restricted protection levels can be set to trap software crashes
and control the system.
Protocol
A system of rules and procedures governing communications between two or more devices. Protocols
vary, but communicating devices must follow the same protocol in order to exchange data. The data
format, readiness to receive or send, error detection, and error correction are some of the operations that
may be defined in protocols.
Proxy
A server that sits between a client application, such as a Web browser, and a real server. It intercepts all
requests to the real server to see if it can fulfill the requests itself. If not, it forwards the request to the real
server.
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PS/2
Stands for Personal System/2 connector, used for keyboards and mice.
PSTN
Stands for called the Public Switched Telephone Network (PSTN).
PSU
Stands for Power Supply Unit.
PUN
An acronym for physical unit number, a term used to describe a device attached directly to the SCSI bus.
Also known as a SCSI ID. As many as eight SCSI devices can be attached to a single SCSI bus, and
each must have a unique PUN or ID assigned from 7 to 0. Normally the SCSI host adapter is assigned the
highest-priority ID, which is 7. A bootable hard disk is assigned an ID of 6, and other non-bootable drives
are assigned lower priorities.
PVC
Stands for Permanent Virtual Circuit. Also stands for poly-vinyl chloride, a component in plastic items.
QAM
An acronym for quadrature amplitude modulation, a modulation technique used by high-speed modems
that combines both phase and amplitude modulation. This technique enables multiple bits to be encoded
in a single time interval. The V.32bis standard-codes six data bits plus an additional trellis coding bit for
each signal change. An individual signal is evaluated with respect to phase and amplitude compared to
the carrier wave. A plot of all possible QAM signal points is referred to as the signal constellation pattern.
The V.32bis constellation pattern has 128 discrete signal points.
QIC
Quarter-Inch Committee. An industry association that sets hardware and software standards for
tape-backup units that use quarter-inch-wide tapes.
QoS
Stands for Quality of Service, a key component for voice-over-IP systems (like telephones).
QWERTY keyboard
The standard typewriter or computer keyboard, with the characters Q, W, E, R, T, and Y on the top row of
alpha keys. Because of the haphazard placement of characters, this keyboard can hinder fast typing.
Rails
Plastic strips attached to the sides of disk drives mounted in IBM ATs and compatibles so that the drives
can slide into place. These rails fit into channels in the side of each disk drive bay
position.
RAM
An acronym for random-access memory, all memory accessible at any instant (randomly) by a
microprocessor.
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RAM disk
A phantom disk drive in which a section of system memory (RAM) is set aside to hold data, just as though
it were a number of disk sectors. To DOS, a RAM disk looks like and functions like any other drive.
Random-access file
A file in which all data elements (or records) are of equal length and written in the file end to end, without
delimiting characters between. Any element (or record) in the file can be found directly by calculating the
record's offset in the file.
RAS
Stands for Remote Access Service.
RDP
Stands for Remote Desktop Protocol.
Read-only file
A file whose attribute setting in the file's directory entry tells DOS not to allow software to write into or over
the file.
Read/write head
A tiny magnet that reads and writes data on a disk track.
Real mode
A mode available in all Intel 8086-compatible processors that enables compatibility with the original 8086.
In this mode, memory addressing is limited to one megabyte.
Real time
When something is recorded or processed as it is happening in the outside world.
Red Book
Red Book is more commonly known as Compact Disc Digital Audio (CD-DA) and is one of four compact
disk standards. Red Book got its name from the color of the manual used to describe the CD Audio
specifications. The Red Book audio standard requires that digital audio is sampled at a 44.1KHz sample
rate using 16 bits for each sample. This is the standard used by audio CDs and many CD ROMs. Sample
rates this high require enormous amounts of disk space.
Refresh cycle
A cycle in which the computer accesses all memory locations stored by dynamic RAM chips so that the
information remains intact. Dynamic RAM chips must be accessed several times a second, or else the
information fades.
Register
Storage area in memory having a specified storage capacity, such as a bit, a byte, or a computer word,
and intended for a special purpose.
Remote digital loopback
A test that checks the phone link and a remote modem's transmitter and receiver. Data entered from the
keyboard is transmitted from the initiating modem, received by the remote modem's receiver, looped
through its transmitter, and returned to the local screen for verification.
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Remote echo
A copy of the data received by the remote system, returned to the sending system, and displayed
on-screen. A function of the remote system.
Resolution
A reference to the size of the pixels used in graphics. In medium-resolution graphics, pixels are large. In
high-resolution graphics, pixels are small.
RF
Stands for Radio Frequency.
RFI
An acronym for Radio Frequency Interference, a high frequency signal radiated by improperly shielded
conductors, particularly when signal path lengths are comparable to or longer than the signal
wavelengths. The Federal Communications Commission now regulates RFI in computer equipment sold
in the US under FCC Regulations Part 15, Subpart J.
RGB
Stands for Red, Green, Blue.
RIP
Stands for Routing Information Protocol.
RIS
Stands for Remote Installation Service.
RISC
An acronym for Reduced Instruction Set Computer, as differentiated from CISC, Complex Instruction Set
Computer. RISC processors have simple instruction sets requiring only one or a few execution cycles.
These simple instructions can be utilized more effectively than CISC systems with appropriately designed
software, resulting in faster operations.
RLL
1) An acronym for Run-Length Limited, a type of encoding that derives its name from the fact that the
techniques used limit the distance (run length) between magnetic flux reversals on the disk platter.
Several types of RLL encoding techniques exist, although only two are commonly used. (1,7)RLL
encoding increases storage capacity by about 30 percent over MFM encoding and is most popular in the
very highest capacity drives due to a better window margin, while (2,7)RLL encoding increases storage
capacity by 50 percent over MFM encoding and is used in the majority of RLL implementations. Most IDE,
ESDI, and SCSI hard disks use one of these forms of RLL encoding.
2) An acronym for Run length limited, a data encoding scheme which guarantees that there is some
maximum period between signal transitions whatever the data. In this sense, RLL is roughly synonymous
with self-clocking. Nearly all serial recording is done using some form of RLL code, however the term is
usually reserved for those more sophisticated group codes which allow comparatively long maximum
runs between transitions, but also guarantee some minimum run length of at least two code bit periods
between transitions, allowing higher storage densities.
RMA number
Return-merchandise authorization number. A number given to you by a vendor when you arrange to
return an item for repairs. Used to track the item and the repair.
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ROM
An acronym for read-only memory, a type of memory that has values permanently or semi-permanently
burned in. These locations are used to hold important programs or data that must be available to the
computer when the power initially is turned on.
ROM BIOS
An acronym for Read Only Memory-Basic Input Output System. A BIOS encoded in a form of read-only
memory for protection. Often applied to important start-up programs that must be present in a system for
it to operate.
Root directory
The main directory of any hard or floppy disk. Has a fixed size and location for a particular disk volume
and cannot be resized dynamically the way subdirectories can.
Routine
Set of frequently used instructions. May be considered as a subdivision of a program with two or more
instructions that are related functionally.
RS-232
An interface introduced in August 1969 by the Electronic Industries Association. The RS-232 interface
standard provides an electrical description for connecting peripheral devices to PCs.
RTC
Stands for Real-Time Clock.
S-Video (Y/C)
Y/C video is a video signal in which the luminance and chrominance (Y/C) components are kept
separate, providing greater control and quality of each image. The luminance (Y) channel controls light
intensity. The greater the luminance, the lighter the color. Chrominance (C) contains hue (color) and
saturation (depth) information on an image. Examples of Y/C (S-Video) include S-VHS (Super-VHS) and
Hi8 (High band 8mm) video.
SAN
Stands for Storage Area Network
SAS
Stands for Serial-Attached SCSI, a type of hard drive array.
SATA
Stands for Serial Advanced Technology Attachment, a type of hard drive and disk interface.
SC
Stands for Subscription Channel.
SCP
Stands for Secure Copy Protection.
Scratch disk
A disk that contains no useful information and can be used as a test disk. IBM has a routine on the
Advanced Diagnostics disks that creates a specially formatted scratch disk to be used for testing floppy
drives.
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SCSI
An acronym for Small Computer System Interface, a standard originally developed by Shugart
Associates (then called SASI for Shugart Associates System Interface) and later approved by ANSI in
1986. Uses a 50-pin connector (or 68-pin connector) and permits multiple devices (up to eight including
the host) to be connected in daisy-chain fashion using ID jumpers similar to IDE master/slave jumpers.
SD Card
A type of memory storage card found primarily in cameras, tablets and smartphones.
SDLC
Synchronous Data Link Control. A protocol developed by IBM for software applications and
communicating devices operation in IBM's Systems Network Architecture (SNA). Defines operations at
the link level of communications; for example, the format of data frames exchanged between modems
over a phone line.
SEC
Stands for Single Edge Connector.
SECAM
A mnemonic term for sequential and memory. Refers to a system of TV broadcasting used in France and
in a modified form in the USSR. Uses an 819-line picture that provides a better resolution than the
(British) PAL 625-line and (U.S.) NTSC 525-line formats.
Sector
A section of one track, defined with identification markings and an identification number. Most sectors
hold 512 bytes of data.
Security software
Utility software that uses a system of passwords and other devices to restrict an individual’s access to
subdirectories and files.
Seek time
The amount of time required for a disk drive to move the heads across one-third of the total number of
cylinders. Represents the average time it takes to move the heads from one cylinder to another randomly
selected cylinder. Seek time is a part of the average access time for a drive. See head seek.
Semiconductor
A substance, such as germanium or silicon, whose conductivity is poor at low temperatures but is
improved by minute additions of certain substances or by the application of heat, light, or
voltage. Depending on the temperature and pressure, a semiconductor can control a flow of electricity.
Semiconductors are the basis of modern electronic-circuit technology.
Sequencer
A sequencer is a software program that controls MIDI (Musical Instrument Digital Interface) file messages
and keeps track of music timing. Since MIDI files store note instructions instead of actual sounds, a
sequencer is needed to play, record and edit MIDI sounds. Sequencer programs allow for recording and
playback of MIDI files by storing the instrument, the note pitch (frequency), the duration in real time that
each note is held and the loudness (amplitude) of each musical or sound effect note.
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Sequential file
A file in which varying-length data elements are recorded end to end, with delimiting characters placed
between each element. To find a particular element, you must read the whole file up to that element.
Serial
The transfer of data characters one bit at a time, sequentially, using a single electrical path.
Servo data
Magnetic markings written on disk platters to guide the read/write heads in drives that use voice-coil
actuators.
Session (Single or Multi-Session)
A term used in CD-ROM recording to describe a recording event. In a single session, data is recorded
on a CD-ROM disk and an index is created. If additional space is left on the disk, another session can be
used to record additional files along with another index. The original index cannot be updated because
recordable CD-ROM drives are normally Write Once Read Many (WORM) type drives. Many CD-ROM
drives do not expect additional recording sessions and therefore will be unable to read the additional
session data on the disk. The advent of Kodak's Photo CD propelled the desire for multisession CD-ROM
XA (extended architecture) drives. The first generation of XA drives were capable of single session reads
only. Multi-session CD-ROM XA drives will read all the indices created when images are recorded many
times on the same CD-ROM XA drive.
Settling time
The time required for read/write heads to stop vibrating after they have been moved to a new track.
SFC
Stands for System File Checker, a Microsoft utility program.
SFF
Stands for Small Form Factor.
Shadow ROM
A copy of a system's slower access ROM BIOS placed in faster access RAM, usually during the start-up
or boot procedure. This setup enables the system to access BIOS code without the penalty of additional
wait states required by the slower ROM chips.
Shell
The generic name of any user interface software. COMMAND.COM is the standard shell for DOS. OS/2
comes with three shells: a DOS command shell, an OS/2 command shell, and the OS/2 Presentation
Manager, a graphical shell. Explorer is the graphical shell for Windows 9x and later Windows versions.
Shock rating
A rating (usually expressed in G force units) of how much shock a disk drive can sustain without damage.
Usually two different specifications exist for a drive powered on or off.
SIMM
Single in-line memory module. An array of memory chips on a small PC board with a single row of I/O
contacts.
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Single-ended
An electrical signaling method where a single line is used referenced to a ground path common to other
signals. In a single-ended bus intended for moderately long distances there is commonly one ground line
between groups of signal lines to provide some resistance to signal cross-talk. Single-ended signals only
require one driver or receiver pin per signal, plus one ground pin per group of signals. Single-ended
signals are vulnerable to common mode noise and cross talk, but are much less expensive than
differential signaling methods.
SIP
Single In-line Package. A DIP-like package with only one row of leads.
Skinny dip
Twenty-four- and 28-position DIP devices with .300-inch row-to-row centerlines.
SLI
Stands for Scalable Link Interface.
SMART
Stands for Self-Monitoring, Analysis and Reporting Technology, which hard drives use to determine the
unit’s health or lack thereof.
SMB
Stands for Server Message Block, or small-to-midsize business.
SMPTE Time Code
SMPTE is an acronym for the Society of Motion Picture and Television Engineers. The SMPTE time code
is a standard used to identify individual video frames in the video editing process. SMPTE time code
controls such functions as play, record, rewind and forward of video tapes. SMPTE time code displays
video in terms of hours, minutes, seconds and frames for accurate video editing.
SMTP
Stands for Simple Mail Transfer Protocol, used in sending email message over the Internet.
SNMP
Stands for Simple Network Management Protocol.
SODIMM
Small-order dual in-line memory module. An array of memory chips on a small PC board with 2 rows of
I/O contacts, used in laptop computers.
SOHO
Stands for Small Office/Home Office, a type of small network of computers and devices.
SO-J
Small Outline J-lead. A small DIP package with J-shaped leads for surface mounting or socketing.
Soft error
An error in reading or writing data that occurs sporadically, usually because of a transient problem such
as a power fluctuation.
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Software
A series of instructions loaded in the computer's memory that instructs the computer in how to accomplish
a problem or task.
SP
Stands for Service Pack, and updating program.
SPDIF
Stands for Sony-Philips Digital Interface Format.
SPGA
Stands for Staggered Pin-Grid Array, used in the design of CPU chips.
Spindle
The central post on which a disk drive's platters are mounted.
Spyware
Any software that covertly gathers user information through the user's Internet connection without his or
her knowledge, usually for advertising purposes. Spyware applications are typically bundled as a hidden
component of freeware or shareware programs that can be downloaded from the Internet; however, it
should be noted that the majority of shareware and freeware applications do not come with spyware.
Once installed, the spyware monitors user activity on the Internet and transmits that information in the
background to someone else. Spyware can also gather information about e-mail addresses and even
passwords and credit card numbers.
SQL
An acronym for structured query language. A standard relational database language used especially on
midrange and mainframe computers.
SRAM
Stands for Static Random Access Memory, a fast type of memory used in CMOS chips.
SSH
Stands for Secure Shell, used for encrypted transfers of data files over the Internet or network.
SSID
Stands for Service Set Identifier, or the name of your home (or business) wireless router.
SSL
Stands for Secure Sockets Layer.
ST
Stands for Straight Tip, a type of fiber optic cable connector.
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ST-506/412
A hard disk interface invented by Seagate Technology and introduced in 1980 with the ST-506 5M hard
drive. The ST-506 interface requires that the read/write head be stepped or moved across the disk one
track at a time by carefully timed pulses. Because these pulses cause the read/write head-stepper motor
to advance a notch, they cannot be sent faster than the disk drive can move the heads. The ST-412
interface introduced with the ST-412 10M drive adds buffered seeking, which eliminates this problem.
Instead of requiring the controller to slow the pulse rate to whatever the mechanism can handle, ST-412
simply counts the pulses as they come in and then decides how far to step the head to move the required
number of tracks. ST-506/412 was formerly the interface of choice for IBM-compatible systems but has
since been superseded by the ESDI, IDE, and SCSI interfaces.
Standby power supply
A backup power supply that quickly switches into operation during a power outage.
Start/stop bits
The signaling bits attached to a character before the character is transmitted during asynchronous
transmission.
Starting cluster
The number of the first cluster occupied by a file. Listed in the directory entry of every file.
Stepper motor actuator
An assembly that moves disk drive read/write heads across platters by a sequence of small partial turns
of a stepper motor.
Storage
Device or medium on or in which data can be entered or held, and retrieved at a later time. Synonymous
with memory.
STP
Stands for Shielded Twisted Pair, a type of network cable.
Streaming
In tape backup, a condition in which data is transferred from the hard disk as quickly as the tape drive can
record the data so that the drive does not start and stop or waste tape.
String
A sequence of characters composed of both alphabetical characters and numerals treated as a set in a
program.
Subnet mask
Used to determine what subnet an IP address belongs to. An IP address has two components, the
network address and the host address. Subnetting enables the network administrator to further divide the
host part of the address into two or more subnets.
Subdirectory
A directory listed in another directory. Subdirectories themselves exist as files.
Subroutine
A segment of a program that can be executed by a single call. Also called program module.
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Surface mount
Chip carriers and sockets designed to mount to the surface of a PC board. See chip carrier.
Surge protector
A device in the power line that feeds the computer, that provides minimal protection against voltage
spikes and other transients.
SXGA
Stands for Super eXtended Graphics Array, a type of video card and display format.
Synchronous communication
A form of communication in which blocks of data are sent at strictly timed intervals. Because the timing is
uniform, no start or stop bits are required. Compare with asynchronous communication. Some
mainframes support only synchronous communications unless a synchronous adapter and appropriate
software have been installed.
System crash
A situation in which the computer freezes up and refuses to proceed without rebooting. Usually caused by
faulty software. Unlike a hard disk crash, no permanent physical damage occurs.
System files
The two hidden DOS files IBMBIO.COM / IO.SYS and IBMDOS.COM / MSDOS.SYS; they represent the
interface between the BIOS and DOS (IBMBIO) and the interface between DOS and other applications
(IBMDOS).
System integrator
A computer consultant or vendor who tests available products and combines them into highly optimized
systems.
Target
A device attached to a SCSI bus that receives and processes commands sent from another device (the
initiator) on the SCSI bus. A SCSI hard disk is an example of a target.
TCM
An acronym for trellis-coded modulation, an error-detection and correction technique employed by
high-speed modems to enable higher-speed transmissions that are more resistant to line impairments. In
TCM encoding, the first two data bits of an encoded group are used to generate a third TCM bit that is
added to the group. For example, in V.32bis, the first two bits of a 6-bit group are used to generate the
TCM bit, which then is placed as the first bit of a new 7-bit group. By reversing the encoding at the other
end, the receiving modem can determine whether the received group is valid.
TCP/IP
Stands for Transmission Control Protocol/Internet Protocol, which allows computers to communicate
over the Internet and networks.
TDR
Stands for Time Domain Reflector.
Temporary backup
A second copy of a work file, usually having the extension BAK. Created by application software so that
you easily can return to a previous version of your work. See backup.
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Temporary file
A file temporarily (and usually invisibly) created by a program for its own use.
Tera
A multiplier indicating 1 trillion (1,000,000,000,000) of some unit. Abbreviated as t or T. When used to
indicate a number of bytes of memory storage, the multiplier definition changes to 1,099,511,627,776.
One terabit, for example, equals 1,000,000,000,000 bits, and one terabyte equals 1,099,511,627,776
bytes.
Terabyte (TB)
A unit of information storage equal to 1,099,511,627,776 bytes.
Terminal
A device whose keyboard and display are used for sending and receiving data over a communications
link. Differs from a microcomputer in that it has no internal processing capabilities. Used to enter data
into or retrieve processed data from a system or network.
Terminal mode
An operational mode required for microcomputers to transmit data. In terminal mode, the computer acts
as though it were a standard terminal such as a teletypewriter rather than a data processor. Keyboard
entries go directly to the modem, whether the entry is a modem command or data to be transmitted over
the phone lines. Received data is output directly to the screen. The more popular communications
software products control terminal mode and enable more complex operations, including file transmission
and saving received files.
Terminator
A piece of hardware that must be attached to both ends of an electrical bus. Functions to prevent the
reflection or echoing of signals that reach the ends of the bus and to ensure that the correct impedance
load is placed on the driver circuits on the bus.
TFTP
Stands for Trivial File Transfer Protocol.
Thin-film media
Hard disk platters that have a thin film (usually 3 millionths of an inch) of medium deposited on the
aluminum substrate through a sputtering or plating process.
Through-hole
Chip carriers and sockets equipped with leads that extend through holes in a PC board. See chip carrier.
Throughput
The amount of user data transmitted per second without the overhead of protocol information such as
start and stop bits or frame headers and trailers.
TIFF
An acronym for Tagged Image File Format, a way of storing and exchanging digital image data.
Developed by Aldus Corporation, Microsoft Corporation, and major scanner vendors to help link
scanned images with the popular desktop publishing applications. Supports three main types of image
data: black-and-white data, halftones or dithered data, and gray-scale data.
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TKIP
Stands for Temporal Key Integrity Protocol.
Token ring
A type of local area network in which the workstations relay a packet of data called a token in a logical ring
configuration. When a station wants to transmit, it takes possession of the token, attaches its data, then
frees the token after the data has made a complete circuit of the electrical ring. IBM's token ring system is
a standard network hardware implementation supported by many manufacturers. Because of the
token-passing scheme, access to the network is controlled, unlike the EtherNet system, in which
collisions of data can occur, wasting time. The token ring network also uses twisted-pair wiring.
TPI
Tracks per inch. Used as a measurement of magnetic track density. Standard 51/4-inch 360K floppy
disks have a density of 48 TPI, and the 1.2M disks have a 96-TPI density. All 31/2-inch disks have a
135.4667-TPI density, and hard disks can have densities greater than 3,000 TPI.
TPM
Stands for Trusted Platform Module, used with encryption and security programs.
Track
One of the many concentric circles that hold data on a disk surface. Consists of a single line of magnetic
flux changes and is divided into some number of 512-byte sectors.
Track density
Expressed as Tracks Per Inch (TPI), track density defines how many tracks are recorded in one inch of
space measured radially from the center of the disk. Sometimes also called radial density
Track-to-track seek time
The time required for read/write heads to move between adjacent tracks.
Transportable computer
A computer system larger than a portable system, and similar in size and shape to a portable sewing
machine. Most transportable computers conformed to a design similar to the original COMPAQ portable,
with a built-in CRT display. These systems are characteristically very heavy, and run only on AC power.
Because of advances primarily in LCD and plasma-display technology, these systems are obsolete and
have been replaced by portable systems.
Troubleshooting
The task of determining the cause of a problem.
True-Color Images
True-color images are also called 24-bit color images since each pixel is represented by 24 bits of data.
allowing for 16.7 million colors. The number of colors possible is based on the number of bits used to
represent the color. If 8-bits are used, there are 256 possible color values (2 to the 8th power). To obtain
16.7 million colors, each of the primary colors (red, green and blue) is represented by 8-bits per pixel,
which allows for 256 possible shades for each of the primary red, green and blue colors or 256x256x256
= 16.7 million total colors.
TSR
An acronym for terminate-and-stay-resident, a program that remains in memory after being loaded.
Because they remain in memory, TSR programs can be reactivated by a predefined keystroke sequence
or other operation while another program is active. Usually called resident programs.
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TTL
An acronym for transistor-to-transistor logic. Digital signals often are called TTL signals. A TTL display is
a monitor that accepts digital input at standardized signal voltage levels.
Tweens
Tweens are the name given to a series of animation or video frames between the key frames. When one
object is transformed (morphed) into another, the initial object and the final object are set on the
computer. Tweens are the frames that transpose the first object into the final image.
Twisted pair
A type of wire in which two small insulated copper wires are wrapped or twisted around each other to
minimize interference from other wires in the cable. Two types of twisted-pair cables are available:
unshielded and shielded. Unshielded twisted-pair wiring commonly is used in telephone cables and
provides little protection against interference. Shielded twisted-pair wiring is used in some networks or
any application in which immunity from electrical interference is more important. Twisted-pair wire is
easier to use with than coaxial cable and is cheaper as well.
UAC
Stands for User Account Control.
UART
An acronym for Universal Asynchronous Receiver Transmitter, a chip device that controls the RS-232
serial port in a PC-compatible system. Originally developed by National Semiconductor, several UART
versions are in PC-compatible systems: the 8250B is used in PC- or XT-class systems, and the 16450
and 16550A are used in AT-class systems.
UDF
Stands for User-Defined Functions, or universal disk format.
UDP
Stands for User Datagram Protocol, which allows audio/video streaming on the Internet.
UEFI
Stands for Unified Extensible Firmware Interface, used with newer system BIOS chips on motherboards.
UNC
Stands for Universal Naming Convention.
Unformatted capacity
The total number of bytes of data that can be fit on a disk. The formatted capacity is lower because space
is lost defining the boundaries between sectors.
UPC
An acronym for Universal Product Code, a ten-digit computer-readable bar code used in labeling retail
products. The code in the form of vertical bars includes a five-digit manufacturer identification number
and a five-digit product code number.
Update
To modify information already contained in a file or program with current information.
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UPS
An acronym for uninterruptible power supply. A device that supplies power to the computer from batteries
so that power will not stop, even momentarily, during a power outage. The batteries are recharged
constantly from a wall socket.
URL
Stands for Uniform Resource Locator.
USB
Stands for Universal Serial Bus, a connection standard for devices.
USMT
Stands for User State Migration Tool, a Microsoft utility program.
Utility
Programs that carry out routine procedures to make computer use easier.
UTM (or USM)
Unified threat management (UTM) or unified security management (USM), is a solution in the network
security industry. It has become established as a primary network gateway defense solution for
organizations. In theory, UTM is the evolution of the traditional firewall into an all-inclusive security
product able to perform multiple security functions within one single system: network firewalling, network
intrusion prevention and gateway antivirus (AV), gateway anti-spam, VPN, content filtering, load
balancing, data loss prevention and on-appliance reporting.
UTP
An acronym for unshielded twisted pair, a type of wire often used indoors to connect telephones or
computer devices. Comes with two or four wires twisted inside a flexible plastic sheath or conduit and
utilizes modular plugs and phone jacks.
UXGA
Stands for Ultra eXtended Graphics Array, a type of video card and display format.
V.21
A CCITT standard for modem communications at 300 bps. Modems made in the U.S. or Canada follow
the Bell 103 standard but can be set to answer V.21 calls from overseas. The actual transmission rate is
300 baud and employs FSK (frequency shift keying) modulation, which encodes a single bit per baud.
V.22
A CCITT standard for modem communications at 1200 bps, with an optional fallback to 600 bps. V.22 is
partially compatible with the Bell 212A standard observed in the United States and Canada. The actual
transmission rate is 600 baud, using DPSK (differential-phase shift keying) to encode as much as 2 bits
per baud.
V.22bis
A CCITT standard for modem communications at 2400 bps. Includes an automatic link-negotiation
fallback to 1200 bps and compatibility with Bell 212A/V.22 modems. The actual transmission rate is 600
baud, using QAM (quadrature amplitude modulation) to encode as much as 4 bits per baud.
V.23
A CCITT standard for modem communications at 1200 or 600 bps with a 75-bps back channel. Used in
the United Kingdom for some videotext systems.
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V.25
A CCITT standard for modem communications that specifies an answer tone different from the Bell
answer tone used in the U.S. and Canada. Most intelligent modems can be set with an ATB0
command so that they use the V.25 2100 Hz tone when answering overseas calls.
V.32
A CCITT standard for modem communications at 9600 bps and 4800 bps. V.32 modems fall back to 4800
bps when line quality is impaired and fall forward again to 9600 bps when line quality improves. The
actual transmission rate is 2400 baud, using QAM (quadrature amplitude modulation) and optional TCM
(trellis-coded modulation) to encode as much as 4 data bits per baud.
V.32bis
A CCITT standard that extends the standard V.32 connection range and supports 4800-, 7200-, 9600-,
12000-, and 14400-bps transmission rates. V.32bis modems fall back to the next lower speed when line
quality is impaired, fall back further as necessary, and fall forward to the next higher speed when line
quality improves. The actual transmission rate is 2400 baud, using QAM (quadrature amplitude
modulation) and TCM (trellis-coded modulation) to encode as much as 6 data bits per baud.
V.32fast
A CCITT standard that extends the standard V.32bis connection range, supporting 28800-bps
transmission rates as well as all the functions and rates of V.32bis.
V.32terbo
A proprietary standard proposed by several modem manufacturers which will be cheaper to implement
than the standard V.32 fast protocol, but which will only support transmission speeds of up to 18800-bps.
Since it is not an industry standard, it is not likely to have widespread industry support.
V.42
A CCITT standard for modem communications that defines a two-stage process of detection and
negotiation for LAPM error control. Also supports MNP error-control protocol, Levels 1 through 4.
V.42bis
An extension of CCITT V.42 that defines a specific data-compression scheme for use with V.42 and MNP
error control.
Vaccine
A type of program used to locate and eradicate virus code from infected programs or systems.
VCPI
An acronym for Virtual Control Program Interface, a 386 and higher processor memory management
standard created by Phar Lap software in conjunction with other software developers. VCPI provides an
interface between applications using DOS extenders and 386 memory managers.
VESA
An acronym for the Video Electronics Standards Association. Founded in the late 1980s by NEC Home
Electronics and eight other leading video board manufacturers, with the main goal to standardize the
electrical, timing, and programming issues surrounding 800-by-600 resolution video displays, commonly
known as Super VGA. VESA has also developed the Video Local Bus (VL-Bus) standard for connecting
high speed adapters directly to the local processor bus.
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VFAT
Stands for Virtual File Allocation Table.
VGA
An acronym for Video Graphics Array, a type of PC video display circuit (and adapter) first introduced by
IBM on April 2, 1987, that supports text and graphics. Text is supported at a maximum resolution of 80x25
characters in 16 colors with a character box of 9x16 pixels. Graphics is supported at a maximum
resolution of 320x200 pixels in 256 (from a palette of 262,144) colors or 640x480 pixels in 16 colors. The
VGA outputs an analog signal with a horizontal scanning frequency of 31.5 KHz, and supports analog
color or analog monochrome displays.
Virtual disk
A RAM disk or phantom disk drive in which a section of system memory (usually RAM) is set aside to hold
data, just as though it were a number of disk sectors. To DOS, a virtual disk looks like and functions like
any other real drive.
Virtual memory
A technique by which operating systems (including OS/2) load more programs and data into memory
than they can hold. Parts of the programs and data are kept on disk and constantly swapped back and
forth into system memory. The applications software programs are unaware of this setup and act as
though a large amount of memory is available.
Virtual real mode
A mode available in all Intel 80386-compatible processors. In this mode, memory addressing is limited to
4,096 megabytes, restricted protection levels can be set to trap software crashes and control the system,
and individual real mode compatible sessions can be set up and maintained separately from one another.
Virus
A type of resident program designed to attach itself to other programs. Usually at some later time, when
the virus is running, it causes an undesirable action to take place.
VM
Stands for Virtual Machine.
VMM
An acronym for Virtual Memory Manager, a facility in Windows enhanced mode that manages the task of
swapping data in and out of 386 and higher processor virtual real mode memory space for multiple
non-Windows applications running in virtual real mode.
Voice-coil actuator
A device that moves read/write heads across hard disk platters by magnetic interaction between coils of
wire and a magnet. Functions somewhat like an audio speaker, from which the name originated.
VoIP
Stands for Voice-Over-Internet Protocol, used with systems like Skype, Vonage, and so forth.
Voltage regulator
A device that smooths out voltage irregularities in the power fed to the computer.
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Volume
A portion of a disk signified by a single drive specifier. Under DOS V3.3 and later, a single hard disk can
be partitioned into several volumes, each with its own logical drive specifier (C:,D:,E:, and so on).
Volume label
An identifier or name of up to 11 characters that names a disk.
VRAM
An acronym for video random-access memory. VRAM chips are modified DRAMs on video boards that
enable simultaneous access by the host system's processor and the processor on the video board. A
large amount of information thus can be transferred quickly between the video board and the system
processor. Sometimes also called dual-ported RAM.
Wait states
Pause cycles during system operation that require the processor to wait one or more clock cycles until
memory can respond to the processor's request. Enables the microprocessor to synchronize with
lower-cost, slower memory. A system that runs with zero wait states requires none of these cycles
because of the use of faster memory or a memory cache system.
WAN
Stands for Wide Area Network.
WAP
Stands for Wireless Access Point, or wireless access protocol.
WEP
Stands for Wired Equivalent Privacy, an early wireless security protocol.
Whetstone
A benchmark program developed in 1976 and designed to simulate arithmetic-intensive programs used
in scientific computing. Remains completely CPU-bound and performs no I/O or system calls.
Originally written in ALGOL, although the C and Pascal versions became more popular by the late 1980s.
The speed at which a system performs floating-point operations often is measured in units of
Whetstones.
Whitney technology
A term referring to a magnetic disk design which usually has oxide or thin film media, thin film read/write
heads, low floating height sliders, and low mass actuator arms that together allow higher bit densities
than the older Winchester technology. Whitney technology was first introduced with the IBM 3370 disk
drive circa 1979.
WiFi
Stands for Wireless Fidelity, a standard for wireless networking.
Winchester drive
Any ordinary, nonremovable (or fixed) hard disk drive. The name originates from a particular IBM drive in
the 1960s that had 30M of fixed and 30M of removable storage. This 30-30 drive matched the caliber
figure for a popular series of rifles made by Winchester, so the slang term Winchester was applied to any
fixed platter hard disk.
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Winchester technology
The term "winchester" is loosely applied to mean any disk with a fixed or non-removable recording
medium. More precisely, the term applies to a ferrite read/write head and slider design with oxide media
that was first employed in the IBM 3340 disk drive, circa 1973. Most drives today actually use Whitney
technology.
WINS
Stands for Windows Internet Name Service; similar to domain name service, but applies only to Windows
domains.
Wire Frames
Wire frames are the most common technique used to construct a 3-dimensional object for animation. A
wire frame is given coordinates of length, height and width. Wire frames are then filled with textures,
colors and movement. Transforming a wire frame into a textured object is called "rendering".
WLAN
Stands for Wireless Local Area Network.
Word length
The number of bits in a data character without parity, start, or stop bits.
WORM
An acronym for write once, read many (or multiple). An optical mass-storage device capable of storing
many megabytes of information but that can be written to only once on any given area of the disk. A
WORM disk typically holds more than 200M of data. Because a WORM drive cannot write over an old
version of a file, new copies of files are made and stored on other parts of the disk whenever a file is
revised. WORM disks are used to store information when a history of older versions must be maintained.
Recording on a WORM disk is performed by a laser writer that burns pits in a thin metallic film (usually
tellurium) embedded in the disk. This burning process is called "ablation". WORM drives are frequently
used for archiving data.
WPA
Stands for Wireless Protected Access, a wireless security protocol.
WPS
Stands for WiFi Protected Setup.
Write precompensation
A modification applied to write data by a controller in order to alleviate partially the problem of bit shift,
which causes adjacent 1s written on magnetic media to read as though they were further apart. When
adjacent 1s are sensed by the controller, precompensation is used to write them closer together on the
disk, thus enabling them to be read in the proper bit cell window. Drives with built-in controllers normally
handle precompensation automatically. Precompensation normally is required for the inner cylinders of
oxide media drives.
WUXGA
Stands for Wide Ultra eXtended Graphics array, a type of video card and display format.
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XGA
An acronym for eXtended Graphics Array, a type of PC video display circuit (and adapter) first introduced
by IBM on October 30, 1990, that supports text and graphics. Text is supported at a maximum resolution
of 132x60 characters in 16 colors with a character box of 8x6 pixels. Graphics is supported at a maximum
resolution of 1024x768 pixels in 256 (from a palette of 262,144) colors or 640x480 pixels in 65536 colors.
The XGA outputs an analog signal with a horizontal scanning frequency of 31.5 or 35.52 KHz, and
supports analog color or analog monochrome displays.
XMM
An acronym for eXtended Memory Manager, a driver that controls access to Extended Memory on 286
and higher processor systems. HIMEM.SYS is an example of an XMM that comes with DOS.
Xmodem
A file-transfer protocol with error checking developed by Ward Christensen in the mid-1970s and placed
in the public domain. Designed to transfer files between machines running the CP/M operating system
and using 300- or 1200-bps modems. Until the late 1980s, because of its simplicity and public-domain
status, Xmodem remained the most widely used microcomputer file-transfer protocol. In standard
Xmodem, the transmitted blocks are 128 bytes. 1K-Xmodem is an extension to Xmodem that increases
the block size to 1,024 bytes. Many newer file-transfer protocols that are much faster and more accurate
than Xmodem have been developed, such as Ymodem and Zmodem.
XMS
An acronym for eXtended Memory Specification, a Microsoft developed standard that provides a way for
real mode applications to access extended memory in a controlled fashion. The XMS standard is
available from Microsoft.
XON/XOFF
Standard ASCII control characters used to tell an intelligent device to stop or resume transmitting data. In
most systems, typing Ctrl-S sends the XOFF character. Most devices understand Ctrl-Q as XON; others
interpret the pressing of any key after Ctrl-S as XON.
Y-connector
A Y-shaped splitter cable that divides a source input into two output signals.
Yellow Book
Yellow Book is the standard used by Compact Disc Read Only Memory (CD-ROM). Multimedia
applications most commonly use the Yellow Book standard, which specifies how digital information is to
be stored on the CD-ROM and read by a computer. EXtended Architecture (XA) is currently an extension
of the Yellow Book which allows for the combination of different data types (audio and video, for example)
onto one track in a CD ROM. Without XA, a CD-ROM can only access one data type at a time. All
CD-ROM drives are now XA capable.
Ymodem
A file-transfer protocol first released as part of Chuck Forsberg's YAM (yet another modem) program. An
extension to Xmodem, designed to overcome some of the limitations of the original. Enables information
about the transmitted file, such as the file name and length, to be sent along with the file data and
increases the size of a block from 128 to 1,024 bytes. Ymodem-batch adds the capability to transmit
batches or groups of files without operator interruption. YmodemG is a variation that sends the entire file
before waiting for an acknowledgment. If the receiving side detects an error in midstream, the transfer is
aborted. YmodemG is designed for use with modems that have built-in error-correcting capabilities.
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ZIF
Zero insertion force. Sockets that require no force for the insertion of a chip carrier. Usually accomplished
through movable contacts and used primarily in test devices in which chips will be inserted and removed
many times.
ZIP
Zigzag in-line package. A DIP package that has all leads on one edge in a zigzag pattern and mounts in
a vertical plane.
Zmodem
A file-transfer protocol commissioned by Telenet and placed in the public domain. Like Ymodem,
designed by Chuck Forsberg, and developed as an extension to Xmodem to overcome some of that
original protocol's limitations. Among the key features are a 32-bit CRC offering a degree of error
detection many times greater than Xmodem CRC, a server facility, batch transfers, and fast error
recovery. One feature of Zmodem is the capability to continue transmitting a file from where it left off if the
connection has been broken. Zmodem also was engineered specifically to avoid sending certain
sequences, such as ESCape-carriage return-ESCape, that the Telenet network uses to control the
connection. Its speed, accuracy, and file-recovery capabilities make Zmodem the leading protocol for
high-speed modem file transfers.
NOTES
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Chapter 17. Map of A+ IT Specialist Examination (220-801) Objectives
Introduction
In order to receive CompTIA A+ certification a candidate must pass two exams. The first exam is
CompTIA A+ 220-801 Certification Exam. The CompTIA A+ 220-801 examination measures necessary
competencies for an entry-level IT professional with the equivalent knowledge of at least 12 months of
hands-on experience in the lab or field. Successful candidates will have the knowledge required to
assemble components based on customer requirements, install, configure and maintain devices, PCs and
software for end users, understand the basics of networking and security/forensics, properly and safely
diagnose, resolve and document common hardware and software issues while applying troubleshooting
skills. Successful candidates will also provide appropriate customer support; understand the basics of
virtualization, desktop imaging, and deployment.
CompTIA A+ is accredited by ANSI to show compliance with the ISO 17024 Standard and, as such,
undergoes regular reviews and updates to the exam objectives. The following CompTIA A+ 220-801
exam objectives result from subject matter expert workshops and industry-wide survey results regarding
the skills and knowledge required of an entry-level IT professional. The percentages in this document
represent the relative importance of the subject areas (domains) in the associated body of knowledge,
and together establish the foundation of an entry-level IT professional.
This examination blueprint includes domain weighting, test objectives, and example content. Example
topics and concepts are included to clarify the test objectives and should not be construed as a
comprehensive listing of all the content of this examination.
Candidates are encouraged to use this document to guide their studies. The table below lists the domains
measured by this examination and the extent to which they are represented. The CompTIA A+ 220-801
exam is based on these objectives.
Domain
Percentage of Examination
PC Hardware
Networking
Laptops
Printers
Operational Procedures
40%
27%
11%
11%
11%
Total
100%
**Note: The lists of examples provided in bulleted format below each objective are not exhaustive lists.
Other examples of technologies, processes or tasks pertaining to each objective may also be included on
the exam although not listed or covered in this objectives document.
CompTIA is constantly reviewing the content of our exams and updating test questions to be sure our
exams are current and the security of the questions is protected. When necessary, we will publish updated
exams based on existing exam objectives. Please know that all related exam preparation materials will still
be valid.
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1.1 PC Hardware
1.2 Configure and apply BIOS settings.
 Install firmware upgrades – flash BIOS
 BIOS component information
o RAM
o Hard drive
o Optical drive
o CPU
 BIOS configurations
o Boot sequence
o Enabling and disabling devices
o Date/time
o Clock speeds
o Virtualization support
 BIOS security (passwords, drive encryption: TPM, lo-jack)
 Use built-in diagnostics
 Monitoring
o Temperature monitoring
o Fan speeds
o Intrusion detection/notification
o Voltage
o Clock
o Bus speed
1.3
Differentiate between motherboard components, their purposes, and properties.
 Sizes
o ATX
Micro-ATX
o ITX
 Expansion slots
o PCI
o PCI-X
o PCIe
o miniPCI
o CNR
o AGP2x, 4x, 8x
 RAM slots
 CPU sockets
 Chipsets
o North Bridge
o
South Bridge
o CMOS battery
 Jumpers
 Power connections and types
 Fan connector
 Front panel connectors
o USB
o Audio
o Power button
o Power light
o Drive activity lights
o Reset button
 Bus speeds
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1.4
1.5
1.6
Compare and contrast RAM types and features.
Types
o DDR
o DDR2
o DDR3
o SDRAM
o SODIMM
o RAMBUS
o DIMM
o Parity vs. non-parity
o ECC vs. non-ECC
 Single channel vs. dual channel vs. triple channel
o Single sided vs. double sided
 RAM compatibility and speed
Install and configure expansion cards.
Sound cards
Video cards
Network cards
Serial and parallel cards
USB cards
Firewire cards
Storage cards
Modem cards
Wireless/cellular cards
TV tuner cards
Video capture cards
Riser cards












Install and configure storage devices and use appropriate media.
 Optical drives
o CD-ROM
o DVD-ROM
o Blu-Ray
 Combo drives and burners
o CD-RW
o DVD-RW
o Dual Layer DVD-RW
o BD-R
o BD-RE
 Connection types
o External
 USB
 Firewire
 eSATA
 Ethernet
o Internal SATA, IDE and SCSI
 IDE configuration and setup (Master, Slave, Cable Select)
 SCSI IDs (0 – 15)
o Hot swappable drives
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




1.7
Hard drives
o Magnetic
o 5400 rpm
o 7200 rpm
o 10,000 rpm
o 15,000 rpm
 Solid state/flash drives
o Compact flash
o SD
o Micro-SD
o Mini-SD
o xD
o SSD
RAID types
o 0
o 1
o 5
o 10
Floppy drive
Tape drive
Media capacity
o CD
o CD-RW
o DVD-RW
o DVD
o Blu-Ray
o Tape
o Floppy
o DVD DL
Differentiate among various CPU types and features and select the appropriate cooling
method.
 Socket types
o Intel: LGA, 775, 1155, 1156, 1366
o AMD: 940, AM2, AM2+, AM3, AM3+, FM1, F
 Characteristics
o Speeds
o Cores
o Cache size/type
o Hyperthreading
o Virtualization support
o Architecture (32-bit vs. 64-bit)
o Integrated GPU
 Cooling
o Heat sink
o Fans
o Thermal paste
o Liquid-based
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1.8
Compare and contrast various connection interfaces and explain their purpose.
 Physical connections
o USB 1.1 vs. 2.0 vs. 3.0 speed and distance characteristics
 Connector types: A, B, mini, micro
o Firewire 400 vs. Firewire 800 speed and distance characteristics
o SATA1 vs. SATA2 vs. SATA3, eSATA, IDE speeds
o Other connector types
 Serial
 Parallel
 VGA
 HDMI
 DVI
 Audio
 RJ-45
 RJ-11
o Analog vs. digital transmission
 VGA vs. HDMI
 Speeds, distances and frequencies of wireless device connections
o Bluetooth
o IR
o RF
1.9
Install an appropriate power supply based on a given scenario.
 Connector types and their voltages
o SATA
o Molex
o 4/8-pin 12v
o PCIe 6/8-pin
o 20-pin
o 24-pin
o Floppy
 Specifications
o Wattage
o Size
o Number of connectors
o ATX
o Micro-ATX
 Dual voltage options
1.10
Evaluate and select appropriate components for a custom configuration, to meet
customer specifications or needs.
 Graphic / CAD / CAM design workstation
o Powerful processor
o High-end video
o Maximum RAM
 Audio/Video editing workstation
o Specialized audio and video card
o Large fast hard drive
o Dual monitors
 Virtualization workstation
o Maximum RAM and CPU cores
 Gaming PC
o Powerful processor
o High-end video/specialized GPU
o Better sound card
o High-end cooling
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



1.11
1.12
Home Theater PC
o Surround sound audio
o HDMI output
o HTPC compact form factor
o TV tuner
Standard thick client
o Desktop applications
o Meets recommended requirements for running Windows
Thin client
o Basic applications
o Meets minimum requirements for running Windows
Home Server PC
o Media streaming
o File sharing
o Print sharing
o Gigabit NIC
o RAID array
Given a scenario, evaluate types and features of display devices.
 Types
o CRT
o LCD
o LED
o Plasma
o Projector
o OLED
 Refresh rates
 Resolution
 Native resolution
 Brightness/lumens
 Analog vs. digital
 Privacy/antiglare filters
 Multiple displays
Identify connector types and associated cables.
 Display connector types
o DVI-D
o DVI-I
o DVI-A
o DisplayPort
o RCA
o HD15 (i.e. DE15 or DB15)
o BNC
o miniHDMI
o RJ-45
o miniDin-6
 Display cable types
o HDMI
o DVI
o VGA
o Component
o Composite
o S-video
o RGB
o Coaxial
o Ethernet
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
Device connectors and pin arrangements
o SATA
o eSATA
o PATA
 IDE
 EIDE
o Floppy
o USB
o IEEE1394
o SCSI
o PS/2
o Parallel
o Serial
o Audio
o RJ-45
 Device cable types
o SATA
o eSATA
o IDE
o EIDE
o Floppy
o USB
o IEEE1394
o SCSI
 68pin vs. 50pin vs. 25pin
o Parallel
o Serial
o Ethernet
o Phone
1.13
Install and configure various peripheral devices.
 Input devices
o Mouse
o Keyboard
o Touch screen
o Scanner
o Barcode reader
o KVM
o Microphone
o Biometric devices
o Game pads
o Joysticks
o Digitizer
 Multimedia devices
o Digital cameras
o Microphone
o Webcam
o Camcorder
o MIDI enabled devices
 Output devices
o Printers
o Speakers
o Display devices
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2.1 Networking
2.2
2.3
2.4
2.5
Identify types of network cables and connectors.
 Fiber
o Connectors: SC, ST and LC
 Twisted Pair
o Connectors: RJ-11, RJ-45
o Wiring standards: T568A, T568B
 Coaxial
o Connectors: BNC, F-connector
Categorize characteristics of connectors and cabling.
 Fiber
o Types (single-mode vs. multi-mode)
o Speed and transmission limitations
 Twisted pair
o Types: STP, UTP, CAT3, CAT5, CAT5e, CAT6, plenum, PVC
o Speed and transmission limitations
 Coaxial
o Types: RG-6, RG-59
o Speed and transmission limitations
Explain properties and characteristics of TCP/IP.
 IP class
o Class A
o Class B
o Class C
 IPv4 vs. IPv6
 Public vs. private vs. APIPA
 Static vs. dynamic
 Client-side DNS
 DHCP
 Subnet mask
 CIDR vs. subnet mask
 Gateway
Explain common TCP and UDP ports, protocols, and their purpose.
 Ports
o 21 – FTP
o 23 – TELNET
o 25 – SMTP
o 53 – DNS
o 80 – HTTP
o 110 – POP3
o 143 – IMAP
o 443 – HTTPS
o 3389 – RDP
 Protocols
o DHCP
o DNS
o LDAP
o SNMP
o SMB
o CIFS
o SSH
o SFTP
 TCP vs. UDP
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2.6 Compare and contrast wireless networking standards and encryption types.
 Standards
o 802.11 a/b/g/n
o Speeds, distances and frequencies
 Encryption types
o WEP, WPA, WPA2, TKIP, AES
2.7 Install, configure, and deploy a SOHO wireless/wired router using appropriate settings.
 MAC filtering
 Channels (1 – 11)
 Port forwarding, port triggering
 SSID broadcast (on/off)
 Wireless encryption
 Firewall
 DHCP (on/off)
 DMZ
 NAT
 WPS
 Basic QoS
2.8 Compare and contrast Internet connection types and features.
 Cable
 DSL
 Dial-up
 Fiber
 Satellite
 ISDN
 Cellular (mobile hotspot)
 Line of sight wireless internet service
 WiMAX
2.9 Identify various types of networks.
 LAN
 WAN
 PAN
 MAN
 Topologies
o Mesh
o Ring
o Bus
o Star
o Hybrid
2.10
Compare and contrast network devices, their functions, and features.
 Hub
 Switch
o PoE
 Router
 Access point
 Bridge
 Modem
 NAS
 Firewall
 VoIP phones
 Internet appliance
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2.11 Given a scenario, use appropriate networking tools.
 Crimper
 Multimeter
 Toner probe
 Cable tester
 Loopback plug
 Punchdown tool
3.1 Laptops
3.2 Install and configure laptop hardware and components.
 Expansion options
 Express card /34
 Express card /54
 PCMCIA
 SODIMM
 Flash
 Hardware/device replacement
 Keyboard
 Hard Drive (2.5 vs. 3.5)
 Memory
 Optical drive
 Wireless card
 Mini-PCIe
 screen
 DC jack
 Battery
 Touchpad
 Plastics
 Speaker
 System board
 CPU
3.3 Compare and contrast the components within the display of a laptop
 Types
o LCD
LED OLED
o Plasma
 Wi-Fi antenna connector/placement
 Inverter and its function
 Backlight
3.4 Compare and contrast laptopfeatures.
 Special function keys
 Dual displays
 Wireless (on/off)
 Volume settings
 Screen brightness
 Bluetooth (on/off)
 Keyboard backlight
•
Docking station vs. port replicator
 Physical laptop lock and cable lock
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4.1 Printers
4.2
4.3
Explain the differences between the various printer types and
summarize the associated imaging process.
 Laser
o Imaging drum, fuser assembly, transfer belt, transfer roller,
pickup rollers, separate pads, duplexing assembly
o Imaging process: processing, charging, exposing,
developing, transferring, fusing and cleaning
 Inkjet
o Ink cartridge, print head, roller, feeder, duplexing assembly, carriage and belt
o Calibration
 Thermal
o Feed assembly, heating element
o Special thermal paper
 Impact
o Print head, ribbon, tractor feed
o Impact paper



4.4



Given a scenario, install, and configure printers.
Use appropriate printer drivers for a given operating system
Print device sharing
o Wired
 USB
 Parallel
 Serial
 Ethernet
o Wireless
 Bluetooth
 802.11x
 Infrared (IR)
o Printer hardware print server
Printer sharing
o Sharing local/networked printer via Operating System settings
Given a scenario, perform printer maintenance.
Laser
o Replacing toner, applying maintenance kit, calibration, cleaning
Thermal
o Replace paper, clean heating element, remove debris
Impact
o Replace ribbon, replace print head, replace paper
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5.1 Operational Procedures
5.2
Given a scenario, use appropriate safety procedures.
 ESD straps
 ESD mats
 Self-grounding
 Equipment grounding
 Personal safety
o Disconnect power before repairing PC
o Remove jewelry
o Lifting techniques
o Weight limitations
o Electrical fire safety
o CRT safety – proper disposal
o Cable management
 Compliance with local government regulations
5.3
Explain environmental impacts and the purpose of environmental controls.
 MSDS documentation for handling and disposal
 Temperature, humidity level awareness and proper ventilation
 Power surges, brownouts, blackouts
o Battery backup
o Surge suppressor
 Protection from airborne particles
o Enclosures
o Air filters
 Dust and debris
o Compressed air
o Vacuums
 Component handling and protection
o Antistatic bags
 Compliance to local government regulation
5.4
Given a scenario, demonstrate proper communication and professionalism.
Use proper language – avoid jargon, acronyms, slang when applicable
Maintain a positive attitude
Listen and do not interrupt the customer
Be culturally sensitive
Be on time (if late contact the customer)
Avoid distractions
o Personal calls
o Talking to co-workers while interacting with customers
o Personal interruptions
 Dealing with difficult customer or situation
o Avoid arguing with customers and/or being defensive
o Do not minimize customer’s problems
o Avoid being judgmental
o Clarify customer statements (ask open ended questions to narrow the scope of
the problem, restate the issue or question to verify understanding)
 Set and meet expectations/timeline and communicate status with the customer
o Offer different repair/replacement options if applicable
o Provide proper documentation on the services provided
o Follow up with customer/user at a later date to verify satisfaction
 Deal appropriately with customers confidential materials
o Located on a computer, desktop, printer, etc.






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5.5 Explain the fundamentals of dealing with prohibited content/activity.
 First response
o Identify
o Report through proper channels
o Data/device preservation
 Use of documentation/documentation changes
 Chain of custody
o Tracking of evidence/documenting process
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Chapter 18. Map of A+ IT Specialist Examination (220-802) Objectives
Introduction
In order to receive CompTIA A+ certification a candidate must pass two exams. The first exam is the
CompTIA A+ 220-801 Certification Exam. The CompTIA A+ 220-802 Certification Exam is the second exam
required in order for CompTIA A+ certification candidates to complete their certification.
The CompTIA A+ 220-802 examination measures necessary competencies for an entry-level IT professional
with the equivalent knowledge of at least 12 months of hands-on experience in the lab or field. Successful
candidates will have the knowledge required to assemble components based on customer requirements,
install, configure and maintain devices, PCs and software for end users, understand the basics of networking
and security/forensics, properly and safely diagnose, resolve and document common hardware and software
issues while applying troubleshooting skills. Successful candidates will also provide appropriate customer
support; understand the basics of virtualization, desktop imaging, and deployment.
CompTIA A+ is ISO 17024 Accredited (Personnel Certification Accreditation) and, as such, undergoes regular
reviews and updates to the exam objectives. The following CompTIA A+ 220-802 certification exam objectives
result from subject matter expert workshops and industry-wide survey results regarding the skills and
knowledge required of an entry-level IT professional. The percentages in this document represent the relative
importance of the subject areas (domains) in the associated body of knowledge, and together establish the
foundation of an entry-level IT professional.
This examination blueprint includes domain weighting, test objectives, and example content. Example topics
and concepts are included to clarify the test objectives and should not be construed as a comprehensive listing
of all the content of this examination.
Candidates are encouraged to use this document to guide their studies. The table below lists the domains
measured by this examination and the extent to which they are represented. The CompTIA A+ 220-802
certification exam is based on these objectives.
Domain
Percentage of Examination
Operating Systems
Security
Mobile Devices
Troubleshooting
33%
22%
9%
36%
Total
100%
**Note: The lists of examples provided in bulleted format below each objective are not exhaustive lists. Other
examples of technologies, processes or tasks pertaining to each objective may also be included on the exam
although not listed or covered in this objectives document.
CompTIA is constantly reviewing the content of our exams and updating test questions to be sure our exams are current
and the security of the questions is protected. When necessary, we will publish updated exams based on existing exam
objectives. Please know that all related exam preparation materials will still be valid.
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1.1 Operating Systems
1.2 Compare and contrast the features and requirements of various Microsoft Operating Systems.
 Windows XP Home, Windows XP Professional, Windows XP Media Center, Windows XP 64-bit
Professional
 Windows Vista Home Basic, Windows Vista Home Premium, Windows Vista Business, Windows Vista
Ultimate, Windows Vista Enterprise
 Windows 7 Starter, Windows 7 Home Premium, Windows 7 Professional, Windows 7 Ultimate, Windows 7
Enterprise
Features:
 32-bit vs. 64-bit
 Aero, gadgets, user account control, bit-locker, shadow copy, system restore, ready boost, sidebar,
compatibility mode, XP mode, easy transfer, administrative tools, defender, Windows firewall, security
center, event viewer, file structure and paths, category view vs. classic view
Upgrade paths – differences between in place upgrades, compatibility tools, Windows upgrade OS advisor
1.3 Given a scenario, install, and configure the operating system using the most appropriate method.









Boot methods
o USB
o CD-ROM
o DVD
o PXE
Type of installations
o Creating image
o Unattended installation
o Upgrade
o Clean install
o Repair installation
o Multiboot
o Remote network installation
o Image deployment
Partitioning
o Dynamic
o Basic
o Primary
o Extended
o Logical
File system types/formatting
o FAT
o FAT32
o NTFS
o CDFS
o Quick format vs. full format
Load alternate third party drivers when necessary
Workgroup vs. Domain setup
Time/date/region/language settings
Driver installation, software and windows updates
Factory recovery partition
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1.4 Given a scenario, use appropriate command line tools.



Networking
o PING
o TRACERT
o
NETSTAT
o IPCONFIG
o NET
o NSLOOKUP
o NBTSTAT
Operating System
o TASKKILL
o BOOTREC
o SHUTDOWN
o TASKLIST
o MD
o RD
o CD
o DEL
o FDISK
o FORMAT
o COPY
o XCOPY
o ROBOCOPY
o DISKPART
o SFC
o CHKDSK
o [command name] /?
Recovery console
o Fixboot
o Fixmbr
1.5 Given a scenario, use appropriate operating system features and tools.


Administrative
o Computer management
o Device manager
o Users and groups
o Local security policy
o Performance monitor
o Services
o System configuration
o Task scheduler
o Component services
o Data sources
o Print management
o Windows memory diagnostics
o Windows firewall
o Advanced security
MSCONFIG
o General
o Boot
o Services
o Startup
o Tools
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



Task Manager
o Applications
o Processes
o Performance
o Networking
o Users
Disk management
o Drive status
o Mounting
o Extending partitions
o Splitting partitions
o Assigning drive letters
o Adding drives
o Adding arrays
Other
o User State Migration tool (USMT), File and Settings Transfer Wizard, Windows Easy Transfer
Run line utilities
o MSCONFIG
o REGEDIT
o CMD
o SERVICES.MSC
o MMC
o MSTSC
o NOTEPAD
o EXPLORER
o MSINFO32
o DXDIAG
1.6 Given a scenario, use Control Panel utilities (the items are organized by “classic view/large icons” in
Windows).
Common to all Microsoft Operating Systems
 Internet options
o Connections
o Security
o General
o Privacy
o Programs
o Advanced
 Display/Display Settings
o Resolution
 User accounts
 Folder options
o View hidden files
o Hide extensions
o General options
o View options
 System
o Performance (virtual memory)
o Remote settings
o System protection
 Windows firewall
 Power options
o Hibernate
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




Power plans
o Sleep/suspend
o Standby
Unique to Windows XP
o Add/remove programs
o Network connections
o Printers and faxes
o Automatic updates
o Network setup wizard
Unique to Vista
o Tablet PC settings
o Pen and input devices
o Offline files
o Problem reports and solutions
o Printers
Unique to Windows 7
o HomeGroup
o Action Center
Security Center
o Remote Applications and Desktop Connections
o Troubleshooting
1.7 Setup and configure Windows networking on a client/desktop.










HomeGroup, file/print sharing
WorkGroup vs. domain setup
Network shares/mapping drives
Establish networking connections
o VPN
o Dialups
o Wireless
o Wired
o WWAN (Cellular)
Proxy settings
Remote desktop
Home vs. Work vs. Public network settings
Firewall settings
o Exceptions
o Configuration
o Enabling/disabling Windows firewall
Configuring an alternative IP address in Windows
o IP addressing
o Subnet mask
o DNS
o Gateway
Network card properties
o Half duplex/full duplex/auto
o Speed
o Wake-on-LAN
o QoS
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1.8 Perform preventive maintenance procedures using appropriate tools.


Best practices
o Schedules backups
o Scheduled check disks
o Scheduled defragmentation
o Windows updates
o Patch management
o Driver/firmware updates
o Antivirus updates
Tools
o Backup
o System restore
o Check disk
o Recovery image
o Defrag
1.9 Explain the differences among basic OS security settings.





User and groups
o Administrator
o Power user
o Guest
o Standard user
NTFS vs. Share permissions
o Allow vs. deny
o Moving vs. copying folders and files
o File attributes
Shared files and folders
o Administrative shares vs. local shares
o Permission propagation
o Inheritance
System files and folders
User authentication
o Single sign-on
1.10 Explain the basics of client-side virtualization.






Purpose of virtual machines
Resource requirements
Emulator requirements
Security requirements
Network requirements
Hypervisor
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2.1 Security
2.2 Apply and use common prevention methods.




Physical security
o Lock doors
o Tailgating
o Securing physical documents/passwords/shredding
o Biometrics
o Badges
o Key fobs
o RFID badge
o RSA token
o Privacy filters
o Retinal
Digital security
o Antivirus
o Firewalls
o Antispyware
o User authentication/strong passwords
o Directory permissions
User education
Principle of least privilege
2.3 Compare and contrast common security threats.







Social engineering
Malware
Rootkits
Phishing
Shoulder surfing
Spyware
Viruses
o Worms
o Trojans
2.4 Implement security best practices to secure a workstation.







Setting strong passwords
Requiring passwords
Restricting user permissions
Changing default user names
Disabling guest account
Screensaver required password
Disable autorun
2.5 Given a scenario, use the appropriate data destruction/disposal method.



Low level format vs. standard format
Hard drive sanitation and sanitation methods
o Overwrite
o Drive wipe
Physical destruction
o Shredder
o Drill
o Electromagnetic
o Degaussing tool
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2.6 Given a scenario, secure a SOHO wireless network.








Change default user-names and passwords
Changing SSID
Setting encryption
Disabling SSID broadcast
Enable MAC filtering
Antenna and access point placement
Radio power levels
Assign static IP addresses
2.7 Given a scenario, secure a SOHO wired network.





Change default usernames and passwords
Enable MAC filtering
Assign static IP addresses
Disabling ports
Physical security
3.1 Mobile Devices
3.2 Explain the basic features of mobile operating systems.
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Android 4.0.x vs. iOS 5.x
o Open source vs. closed source/vendor specific
o App source (app store and market)
o Screen orientation (accelerometer/gyroscope)
o Screen calibration
o GPS and geotracking
3.3 Establish basic network connectivity and configure email.
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Wireless / cellular data network (enable/disable)
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Bluetooth
o Enable Bluetooth
o Enable pairing
o Find device for pairing
o Enter appropriate pin code
o Test connectivity
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Email configuration
o Server address
 POP3
 IMAP
 Port and SSL settings
o Exchange
o Gmail
3.4 Compare and contrast methods for securing mobile devices.
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Passcode locks
Remote wipes
Locator applications
Remote backup applications
Failed login attempts restrictions
Antivirus
Patching/OS updates
Preparing for A+ Certification: 2016 Edition
A Coursebook in PC Hardware, Maintenance & Repair
Page 367
Copyright, 2016
William A. Lloyd
3.5 Compare and contrast hardware differences in regards to tablets and laptops.
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No field serviceable parts
Typically not upgradeable
Touch interface
o Touch flow
o Multitouch
Solid state drives
3.6 Execute and configure mobile device synchronization.
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Types of data to synchronize
o Contacts
o Programs
o Email
o Pictures
o Music
o Videos
Software requirements to install the application on the PC
Connection types to enable synchronization
4.1 Troubleshooting
4.2 Given a scenario, explain the troubleshooting theory.
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Identify the problem
o Question the user and identify user changes to computer and perform backups before making
changes
Establish a theory of probable cause (question the obvious)
Test the theory to determine cause
o Once theory is confirmed determine next steps to resolve problem
o If theory is not confirmed re-establish new theory or escalate
Establish a plan of action to resolve the problem and implement the solution
Verify full system functionality and if applicable implement preventive measures
Document findings, actions and outcomes
4.3 Given a scenario, troubleshoot common problems related to motherboards, RAM, CPU and power
with appropriate tools.
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Common symptoms
o Unexpected shutdowns
o System lockups
o POST code beeps
o Blank screen on bootup
o BIOS time and settings resets
o Attempts to boot to incorrect device
o Continuous reboots
o No power
o Overheating
o Loud noise
o Intermittent device failure
o Fans spin – no power to other devices
o Indicator lights
o Smoke
o Burning smell
o BSOD
Preparing for A+ Certification: 2016 Edition
A Coursebook in PC Hardware, Maintenance & Repair
Page 368
Copyright, 2016
William A. Lloyd
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Tools
o
o
o
o
Multimeter
Power supply tester
Loopback plugs
POST card
4.4 Given a scenario, troubleshoot hard drives and RAID arrays with appropriate tools.
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Common symptoms
o Read/write failure
o Slow performance
o Loud clicking noise
o Failure to boot
o Drive not recognized
o OS not found
o RAID not found
o RAID stops working
o BSOD
Tools
o Screwdriver
o External enclosures
o CHKDSK
o FORMAT
o FDISK
o File recovery software
4.5 Given a scenario, troubleshoot common video and display issues.

Common symptoms
o VGA mode
o No image on screen
o Overheat shutdown
o Dead pixels
o Artifacts
o Color patterns incorrect
o Dim image
o Flickering image
o Distorted image
o Discoloration (degaussing)
o BSOD
4.6 Given a scenario, troubleshoot wired and wireless networks with appropriate tools.

Common symptoms
o No connectivity
o APIPA address
o Limited connectivity
o Local connectivity
o Intermittent connectivity
o IP conflict
o Slow transfer speeds
o Low RF signal
Preparing for A+ Certification: 2016 Edition
A Coursebook in PC Hardware, Maintenance & Repair
Page 369
Copyright, 2016
William A. Lloyd

Tools
o
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o
o
o
o
o
o
o
o
o
Cable tester
Loopback plug
Punch down tools
Toner probes
Wire strippers
Crimper
PING
IPCONFIG
TRACERT
NETSTAT
NBTSTAT
NET
Wireless locator
4.7 Given a scenario, troubleshoot operating system problems with appropriate tools.

Common symptoms
o BSOD
o Failure to boot
o Improper shutdown
o Spontaneous shutdown/restart
o RAID not detected during installation
o Device fails to start
o Missing .dll message
o Services fails to start
o Compatibility error
o Slow system performance
o Boots to safe mode
o File fails to open
o Missing NTLDR
o Missing Boot.ini
o Missing operating system
o Missing Graphical Interface
o Graphical Interface fails to load
o Invalid boot disk
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Tools
o
o
o
o
o
o
o
o
o
o
o
o
o
o
o
Fixboot
Recovery console
Fixmbr
Sfc
Repair disks
Pre-installation environments
MSCONFIG
DEFRAG
REGSRV32
REGEDIT
Event viewer
Safe mode
Command prompt
Emergency repair disk
Automated system recovery
Preparing for A+ Certification: 2016 Edition
A Coursebook in PC Hardware, Maintenance & Repair
Page 370
Copyright, 2016
William A. Lloyd
4.8 Given a scenario, troubleshoot common security issues with appropriate tools and best practices.
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Common symptoms
o Pop-ups
o Browser redirection
o Security alerts
o Slow performance
o Internet connectivity issues
o PC locks up
o Windows updates failures
o Rogue antivirus
o Spam
o Renamed system files
o Files disappearing
o File permission changes
o Hijacked email
o Access denied
Tools
o Anti-virus software
o Anti-malware software
o Anti-spyware software
o Recovery console
o System restore
o Pre-installation environments
o Event viewer
Best practices for malware removal
o Identify malware symptoms
o Quarantine infected system
o Disable system restore
o Remediate infected systems
Update anti-virus software
Scan and removal techniques (safe mode, pre-installati