Specifications | A++ Certification, hardware mantenance & networking 22012

A++ Certification, hardware mantenance & networking 22012
A++ certification, hardware maintenance & Networking
If you've been in the trenches of end-user support, you know that the same problems seem to
crop up again and again, regardless of the user or the model of PC. This article details some of
the most useful tricks I've learned for troubleshooting hardware problems.
Tip #10: The Right Tools Make all the Difference
Most PC techs have the basic set of tools, of course, like several sizes of Phillips screwdrivers
and some tweezers. But having the following items in my tool chest has saved me more than
once from having to hit the hardware store:
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Torx screwdriver. Torx is that funky six-pointed star type of screw that a few ornery PC
manufacturers (Compaq is a particular offender) like to use to keep ordinary people from
working on their own PCs. Without a Torx screwdriver, you're…well…what the screw is.
Flashlight. I carry one of those Black & Decker snake lights with me for those times
when I'm trying to distinguish between the network card and the modem card underneath
a dark desk. A self-supporting flashlight that you can point in various directions is much
more handy than one you need to keep a hand on at all times.
Compressed air. Yes, you can use compressed air to blow dust bunnies out of a
computer case or from beneath keyboard keys, but it actually has many other uses. For
example, it makes whatever you spray very cold, so you can use it to cool down an
overheated chip. I have also used it successfully to blow a dropped jumper block out of a
crevice that I couldn't reach into.
Extra jumper blocks. Speaking of jumpers, if you do drop or misplace one, having
extras means you don't have to spend the rest of the afternoon crawling around on the
floor looking for it. There are several sizes, so keep a variety on hand.
Extra screws. The same goes with screws -- if you carry extras, you don't have to worry
about the ones you drop and can't find again. Get a variety of sizes.
Masking tape. Masking tape is helpful for securing a cable to a desk temporarily after
you've unplugged it (so it doesn't drop down behind the desk where you can't reach it).
And since you can write on it, you can wrap a piece around each cable you remove from
a motherboard and write a little note on it about where it was plugged in.
Tip #9: The Symptom Is NOT Always Indicative of the Problem
One lesson I have learned the hard way is not to assume that the symptom is the actual problem.
Case in point: Video. When you start up a computer and you don't see any video on the screen,
your first thought might be "bad video card." That answer is correct only about 50 percent of the
time. Other reasons are a faulty processor, a bad motherboard, bad jumper settings on the
motherboard or a memory error. I have even seen cases where a bad adapter card, such as a SCSI
card, threw the whole system into such a funk that no video appeared.
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The same goes with memory errors. Don't assume that a DOS or Windows error that talks about
bad memory necessarily means that your RAM is physically bad. Many underlying causes, such
as operating system file corruption and overheating, can simulate a memory error.
Tip #8: Use a POST Card
When troubleshooting no-video startup problems, one of the most invaluable tools I've found is a
POST card. No, it's not the kind you mail. POST stands for Power On Self Test, and a POST
card is a circuit board you insert into any open bus slot in the motherboard. When you turn on the
power, the POST card's digital display provides a numeric code that lets you know at what point
the boot process is hanging. Then you look up that code in a book that comes with the card, and
you've got your answer.
Tip #7: Take It All Out and Rebuild
Another way to troubleshoot no-video is to remove all nonessential items from the motherboard,
leaving only the power supply, the memory, the processor and the video card. If you still get no
video with only these items in place, there's still troubleshooting to do, but at least you've
narrowed down the possibilities considerably.
A few additional tips from that point:
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If you hear no beeps from the PC speaker, the memory is probably not the problem.
If there is any drive activity at all, it's probably not the processor.
If the cooling fan on the processor is spinning, it's probably not the power supply.
#6: Suspect the Power Supply
There are two problems that can occur with a power supply. One is that it's faulty, the other is
that it's overloaded. Both can potentially result in puzzling errors.
With a faulty power supply, the system probably won't boot at all. It'll seem completely dead.
That's because of the built-in safeguard in the power supply called the Power Good pin. When
you turn on the power supply, it sends a +5v charge through the Power Good pin to the
motherboard. If the motherboard receives it (or at least receives between +3v and +6v), it starts
up the system. If it receives nothing, or any other voltage, it puts itself in a state of perpetual
reset, with the end result being that nothing happens.
Some faulty power supplies are faulty only intermittently. Such problems can result in seemingly
random disk errors and system problems. If you've tried everything else to troubleshoot a
particular system, you might try a new power supply.
Some power supplies might be perfectly good but insufficient for the amount of stuff that's been
jammed into the PC. For example, after you add a new CD-RW drive to a system, you might
suddenly start having boot up problems. The computer might start to boot okay, then go haywire
when the drives start spinning up. That's because disk drives require about twice the wattage
when they initially spin up than they do once they get going, so an under-powered power supply
is going to freak out during the drive spin-up phase. Underpowered systems can also experience
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post-startup errors during activities that access multiple drives at once, like copying a CD-ROM
or transferring files from a hard disk to a floppy disk.
Tip #5: Try the Easy Fix First
Another lesson I've had to learn painfully in my career: Try the easy fix first. If you're having
problems with a CD-ROM drive, for example, try swapping out the ribbon cable before going to
the trouble of taking out the whole CD-ROM drive.
Swapping cables is an easy fix that a lot of technicians forget about. You can test a cable using a
multimeter with the resistance (ohms) setting, pin-by-pin, to see whether any wires inside are
broken. However, if you're like me, you have a whole drawer of ribbon cables in your shop, and
it's much easier just to try a different cable and worry about the old one's condition later.
Along the same lines, many technicians forget to try a different power connector for a drive, or a
different motherboard slot for an adapter card. It's so annoying when you find the problem that
way after trying all the harder fixes first!
Tip #4: Carry Boot Disks for All OSes
I work for many different clients, and I never know what operating system I'm going to find on a
client PC. When the OS won't boot from the hard disk, a bootable floppy is just the ticket, but
many systems are fussy about the OS version of the boot disk matching the OS version installed
on the hard disk. For example, if you are working with a Windows Me PC and boot it with a
Windows 98 startup disk, and then try to use FDISK, you can potentially run into an Incorrect
Operating System Version message.
That's why I try to carry boot disks for all Windows versions in my tool chest. Some OSes don't
have boot disks per se (Windows NT, 2000, and XP come to mind), but for these you can carry
CD versions and then set up the PC's BIOS to boot from the CD-ROM. From there you can abort
the setup utility that starts automatically and get to the Recovery Console, a command-line
interface you can use for troubleshooting.
Tip #3 The Two Phone Jacks on a Modem Are Not Interchangeable.
On most modems there are two identical-looking phone jacks, labeled either with words or
pictures. One is for the Line (the incoming phone line) and the other is for the Phone (the
telephone unit). On most modems the labeling is extremely difficult to see; you have to get right
up on it with a flashlight.
If you get the lines reversed, all manner of odd things can happen. The modem might not find a
dial tone at all, or it might find a dial tone but emit sharp beeps or honks as it operates. (My US
Robotics modem does that. It's quite bizarre sounding!) Or the line might be all staticky such that
you can't get a connection speed higher than 28.8 or so on a 56K modem.
Tip #2: Device Problems Are Often Plug-and-Play Related
If a newly installed device doesn't work, 90 percent of the time it's not the device's fault -- it's a
Windows thing. Windows is supposed to be able to do Plug-and-Play detection for new
hardware, but any variety of quirky things often happens instead:
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Windows might detect the device incorrectly. For example, it might detect your fine new
video card as Standard VGA.
Windows might not be able to determine the device type. For example, it might detect
your modem as Unknown PCI Device.
Windows might not have any free IRQs available, so it might force the new device to
share with some other device with which it has a conflict.
Windows might not notice the new device at all.
When a new device fails to work right out of the box, here's the troubleshooting routine I go
through:
1. Run the setup software that came with the device. This will often install the correct
drivers in Windows and make the device work.
2. Check Device Manager in Windows to make sure there is no resource conflict; resolve it
if one is found.
3. Remove the device from Device Manager and have Windows re-detect it.
4. Visit the device manufacturer's Web site to see if an updated driver or patch is available
that will resolve the problem.
And the number 1 tip is…
Tip #1: Suspect Overheating
Overheating is such an insidious character in PC troubleshooting because it can cause no end to
seemingly random, unrelated errors. For example, suppose you have a client experiencing
random lockups and reboots. You ask what the problem is, and she says it sometimes happens
when she runs her e-mail program and other times when she is using Microsoft Word. What's
really going on is the processor fan isn't spinning up, and after five minutes or so the computer
overheats. Five minutes after she turns on her PC, she is usually checking her e-mail or using
Word, so those factors are just red herrings.
Whenever a computer has a problem intermittently, without any seeming pattern related to
activity, the first thing I check are the cooling fans. Is the power supply fan blowing? Is the
processor fan spinning? Is the cooling mechanism for the processor (fan or heat sink) firmly
attached to the processor?
One easy way to tell whether overheating is an issue is to blow compressed air on the chip.
Compressed air is very cold so it cools the chip off. If it starts working correctly after that, you
know that overheating is the problem.
Other factors can cause overheating. Leaving the cover off a PC as it operates can cause it to
overheat, as can leaving the backplates off open holes in the back, or missing drive bay covers in
the front. You would think that having more air vents in a case would be a plus, but it's actually
bad because of the highly engineered design of today's PC cases. The air gets sucked in, carried
across the components that need to be cooled, and blown back out again. This airflow pattern is
essential for good cooling. When you remove a backplate or drive bay cover, that airflow pattern
changes and some parts don't get cooled that well.
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Lessons Learned the Hard Way
In this article I've outlined 10 of the most important tips and tricks I've learned on-the-job for
troubleshooting hardware. As you begin (or continue) your own PC technician training and daily
work, keep these in mind so you don't have to learn some of these lessons the way I did!
1) to interprate the commands executed by the user.
2) to handle disk input/output settings.
3) loaded in the memory at boot up and remain in the memory at all time.
4) to provide the OS with the mechanism in order to see the additional memory.
5) used to access the high memory area. (himem.sys )
6) it allows the rest of the OS and its programs to interact directory with the system
hardware and the system BIOS.
7) it sets particular values corresponding to the windows environment.
8) used to run particular programs during startup.
There are Many Functions those are Performed by the Operating System But the Main
Goal of Operating system is to Provide the Interface between the user and the hardware
Means Provides the Interface for Working on the System by the user. The various
Functions those are Performed by the Operating System are as Explained below:1) Operating System as a Resource Manager
Operating System Also Known as the Resource Manager Means Operating System
will Manages all the Resources those are Attached to the System means all the
Resource like Memory and Processor and all the Input output Devices those are
Attached to the System are Known as the Resources of the Computer System and the
Operating system will Manage all the Resources of the System. The Operating System
will identify at which Time the CPU will perform which Operation and in which Time the
Memory is used by which Programs. And which Input Device will respond to which
Request of the user means When the Input and Output Devices are used by the which
Programs. So this will manage all the Resources those are attached to the computer
System.
2
Storage Management: Operating System also Controls the all the
Storage Operations means how the data or files will be Stored into the computers
and how the Files will be Accessed by the users etc. All the Operations those are
Responsible for Storing and Accessing the Files is determined by the Operating System
Operating System also Allows us Creation of Files, Creation of Directories and Reading
and Writing the data of Files and Directories and also Copy the contents of the Files and
the Directories from One Place to Another Place.
1)
Process Management : The Operating System also Treats the Process
Management means all the Processes those are given by the user or the Process
those are System ‘s own Process are Handled by the Operating System . The
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Operating System will Create the Priorities foe the user and also Start or Stops the
Execution of the Process and Also Makes the Child Process after dividing the Large
Processes into the Small Processes.
2)
Memory Management: Operating System also Manages the Memory of the
Computer System means Provide the Memory to the Process and Also Deallocate the
Memory from the Process. And also defines that if a Process gets completed then this
will deallocate the Memory from the Processes.
3)
Extended Machine : Operating System also behaves like an Extended
Machine means Operating system also Provides us Sharing of Files between Multiple
Users, also Provides Some Graphical Environments and also Provides Various
Languages for Communications and also Provides Many Complex Operations like using
Many Hardware’s and Software’s.
4)
Mastermind: Operating System also performs Many Functions and for
those Reasons we can say that Operating System is a Mastermind. It provides Booting
without an Operating System and Provides Facility to increase the Logical Memory of
the Computer System by using the Physical Memory of the Computer System and also
provides various Types of Formats Like NTFS and FAT File Systems. And Operating
System also controls the Errors those have been Occurred into the Program and Also
Provides Recovery of the System when the System gets Damaged Means When due to
Some Hardware Failure , if System Doesn’t Works properly then this Recover the
System and also Correct the System and also Provides us the Backup Facility. And
Operating System also breaks the large program into the Smaller Programs those are
also called as the threads. And execute those threads one by one.
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How to use and troubleshoot issues with
Windows Task Manager
Introduction
This article provides basic information about how to use Windows Task Manager to start programs, to
end processes, and to monitor the computer's performance.
Note For information about how to troubleshoot when you receive an error message that Task Manager
has been disabled by your Administrator, click the following article number to view the article in the
Microsoft Knowledge Base:
913623 Error message when you try to open Task Manager on a Windows XP-based computer: "Task
Manager has been disabled by your Administrator"
For information about how to restore the Task Manager menu bar, click the following article number to
view the article in the Microsoft Knowledge Base:
314227 Task Manager Menu Bar and tabs are not visible in Windows XP
This article is intended for a beginning to intermediate computer user.
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MORE INFORMATION
You can use Task Manager to start programs, to start or to end processes, and to view a dynamic display
of your computer's performance.
How to start Task Manager
To start Task Manager, take any of the following actions:
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Press CTRL+ALT+DELETE, and then click Task Manager.
Press CTRL+SHIFT+ESC.
Right-click an empty area of the taskbar, and then click Task Manager.
How to use Task Manager Help
Everything that you might want to know about Task Manager is included in the Task Manager Help file.
Some of the help topics are intended for a general audience. Other topics are intended for a more
advanced audience. To view the Task Manager Help file, follow these steps:
1. Press CTRL+ALT+DELETE, and then click Task Manager.
2. In Task Manager, click Help, and then click Task Manager Help Topics.
In the "Task Manager overview" topic, you can read about the features and uses of Task Manager by
clicking the following topics and reading the topic and all related topics:
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Programs that are running
Processes that are running
Performance measures
How to exit, switch to, or start a program
The Applications tab displays the status of the programs that are running on the computer. To exit,
switch to, or start a program, follow these steps:
1. Click the Applications tab.
2. Do one of the following, as appropriate for the action that you want to perform:
o Exit a program
To exit a program, click the program that you want to exit, and then click End Task.
o
Note When you exit a program in this manner, any unsaved data in that program is lost.
Switch to another program
To switch to another program, click the program that you want to switch to, and then
click Switch To.
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o
Start a program
To start a program, click New Task. In the Create New Task dialog box, click Browse,
locate and select the program that you want to start, click Open, and then click OK.
Note This procedure is very similar to starting a program by using the Run command on
the Start menu.
How to end a process
The Processes tab displays information about the processes that are running on the computer. A
process can be an application that you start or subsystems and services that are managed by the
operating system. To end a process, follow these steps.
Note Proceed with caution when you end a process. If you exit a program in this manner, data that has
not been saved will be lost. If you end a system process, a system component may no longer function
correctly. To match a process with a running program, right-click the program name on the Applications
tab of Windows Task Manager, and then click Go To Process.
1. Click the Processes tab.
2. Do one of the following, depending on the action that you want to perform:
o If you want to end a single process, click the process that you want to end, and then
click End Process.
o If you want to end a process and all processes directly or indirectly related to it, rightclick the process that you want to end, and then click End Process Tree.
How to monitor your computer's performance
Click the Performance tab to view a dynamic overview of the performance of your computer. This
includes the following measures:
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Graphs for CPU and memory usage
The total number of handles, threads, and processes that are running
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Handles are unique identifiers that allow a program to access system resources such as files,
registry keys, fonts, and bitmaps. Threads are objects within processes that run program
instructions.
The total number of kilobytes (KB) that are used for physical, kernel, and commit memory
Note Your system administrator may have implemented a local policy on your computer to disable Task
Manager. In this scenario, you should contact the system administrator or your help desk if you need
local process control or the ability to monitor the computer's performance.
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Hardware Component of Computer System
In our last Chapter we talked about Computer system or Organization of Computers. We know, a
computer system comprises of two major components – Hardware and Software.
We’ll talk about Software in next chapter. Today let’s see the hardware component of computer
system.
Alex defines hardware somehow funny in his CoolNerds.com:
The stuff you can actually see and touch, and would likely break if you threw it out a fifthstory window, is hardware.
It’s funny but it is true! Everything if it breaks when thrown down from five stored building is
hardware.
The physical and tangible parts of a computer are hardware. It includes the devices such as
keyboard, mouse, monitor, printers, motherboard, memory chips, electronic circuitry, expansion
cards, cables, switches and everything you can touch and feel.
There is a very useful analogy to define computer hardware and software. Let’s take an example
of a book. You should be thinking of the cover, the pages and the ink as hardware. At the same
time the words, sentences, paragraphs, and the storyline, i.e. the information held within the book
would represent the software. A computer without software is very much like having a book full
of blank pages, you need the software to make a computer useful – just the same as you need the
words and story to make a book meaningful. Hardware refers to any part of the computer which
is manufactured. It can refer to individual components or a group of components.
Many people love to offer an analogy with human body and soul to clarify the relationship
between hardware and software component of computers. The body is considered as hardware
and the soul that operates human body is equated with the computer software. Without software,
a computer is just a dead body.
Here is some common hardware that you’ll find inside a computer:
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Motherboard
Central Processing Unit (CPU)
Random Access Memory (RAM)
Power Supply
Video Card
Hard Drive
Optical Drive (i.e. BD/DVD/CD drive)
Sound Card
Network Interface Card (NIC)
Analog Modem
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
FireWire/USB Expansion Card
Here is some common hardware that you might find connected to the outside of a computer:
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Keyboard
Mouse
Printer
Scanner
Speakers
Monitor
The following hardware is referred to as network hardware and various pieces are often part of a
home or business network:
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Router
Network Switch
Access Point
Repeater
Bridge
Print Server
Firewall
Network hardware isn’t as clearly defined as some other types of computer hardware. For
example, many home routers will often act as a combination of router, switch, and firewall.
Input Devices – Keyboard, Mouse and Scanner
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Input Unit Devices
A unit of computer system that brings data and instruction into the computer is input unit. It
accepts data or instruction given by user and converts into machine readable code if required.
Keyboard and mouse are the most popular input unit devices. Other devices of this unit are: light
pen, joystick, tracker ball, microphone, scanners, sensors, graphic tablet, touch screen etc.
The term input is used to describe the process of capturing or collecting raw data, at the
beginning of computer based information system, in to a form that is usable by the computer for
processing. Sometimes the data is processed right away(online processing), sometimes hours or
days later or even longer (batch processing), as a result the data is often stored in a computer
usable form, where it can be quickly retrieved at the time of processing with little or no longer
intervention.
Input unit devices can be classified into two groups based on whether the data conversion is
involved or not – direct input devices and indirect input devices:
Direct Input Devices
In this input method, data is already in machine readable form and thus, no need to convert it.
The data is directly feed into computer to process. Some examples of direct input devices are
Point of Sales Terminals (POS), Credit Cards, and Scanners etc. Credit card contains a magnetic
strip that contains data in machine readable form and when you insert the card into ATM
machine, it can directly feed data for processing.
Indirect Input Devices
If the data is in human readable form, it must be converted into machine readable form so that a
computer can process it. This process of data conversion is time consuming and error prone that
causes a major bottleneck in data processing. Some examples of indirect input devices are:
keyboard, mouse and joystick. When you press any key on keyboard, it converts that character
into series of electronic pulses and sends to CPU.
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Keyboard
Keyboard is a standard input device. It is a data entry platform of a computer. A computer key
board is a sophisticated electromechanical component designed to create specialized electronic
codes (scan codes) when a key is pressed. These codes are transmitted along the cables to
computer system unit or terminal, where the incoming code is analyzed and converted in to the
appropriate computer usable code.
Keyboards have five distinct groups of keys:
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Standard type writer keys: resembles a typewriter
Function keys: The top row keys from F1 to F10 or F12
Cursor movement keys: Arrow keys, Home, End, PageUp, PageDown
Numeric keys: a keypad at the right to make it easy to enter numbers
Special purpose keys: Ctrl, Alt, Shift, Del, Insert
Keyboard Layout defines the position of keys in a keyboard. QWERTY is the most popular
keyboard layout. Dvorak, Colemak, JCUKEN are other keyboard layouts for Latin scripts.
Similarly, we have Traditional, Romanized and Nepali keyboard layout for
typing Unicode Nepali script. You can change keyboard layout from Regional and Language
Settings in Control Panel.
Why are traditional keyboard layout places keys in the QWERTY order? Why they are not
alphabetically ordered like ABCDEF….? You’ll really surprise to know that it was developed to
make typing harder and inefficient (do some Googling on this topic). Devorak layout is far better
in keys arrangement and improves the speed and accuracy of typing, but the more surprising
thing is that it is not much common compared to traditional QWERTY.
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Dvorak Keyboard
QWERTY Keyboard
Types of Keyboard
By now, I hope, you don’t confused types of keyboards as QWERTY, Devorak and so on. They
are not type of keyboards but rather the types of keyboard layout. At the same time, I want to
make it clear that the type, as our course defines, is not related to switch technology either. We
look on the history of keyboard and classify keyboards into four types based on the technology
used.
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Types of Keyboards
PC/XT, PC/AT, Enhanced and Windows are the four types of keyboard.
PC/XT (Stands for eXtended Technology) keyboards have 83 keys, function keys (F1 to F10) are
arranged on left hand side. These keyboards are not compatible with AT keyboards (that means
you can’t use them in AT computers).
XT Keyboard
PC/AT (Stands for Advanced Technology) contains 84 keys as SysRq (System Request) key was
introduced. Moreover indicator LEDs for Caps, Scroll and NUM lock are used in AT keyboards.
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AT Keyboard
Enhanced keyboards have 101 to 106 keys based on different language layout.
Windows Keyboards contained 104 to 109 keys based on different language layouts. Win key
and Menu key are the addition on the Windows Keyboards.
Windows Enhanced Keyboard
Mouse
Mouse
A mouse is a device that controls the movement of the cursor or pointer on a display screen. A
mouse is a small object you can roll along a hard on flat surface. Its name is derived from its
shape, which looks like a mouse, its connecting wire that one can imagine to be the mouse tail;
and the fact that one must make it scurry along a surface. As you move the mouse, the pointer on
the display screen moves in the same direction. Mice contain at least one button and sometimes
as many as three, which have different functions depending on what program is running. Some
newer mice also include a scroll wheel for scrolling through long documents.
Mouse was first invented by Douglas Engelbart in 1963.
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There are three types of mouse: Mechanical, Opto-Mechanical and Optical. Mechanical
mouse has a ball on its underside and sensors detect the direction of ball movement to move the
cursor on the screen.Optomechanical mouse are similar to mechanical mouse but they have
optical sensors instead of balls in it.Optical mouse uses laser to detect the mouse movement.
If we look at how a mouse is connected to computer, we can find three types of mouse: Serial
Mouse, PS/2 Mouse, USB Mouse. Serial mouse connect through RS-232C serial port and it is
the simplest of connection. PS/2 mouse connect through PS/2 port and USB Mouse connect
through USB port.
There are some wireless mice in use these days. Cordless mouse (wireless mouse) connects to
the computer through infrared or radio wave to communicate with computer. Though cordless
mouse are more expensive, they can be greatly useful in some situations.
Scanner
Scanner
A scanner is a device that captures images from photographic prints, posters, magazine pages,
and similar sources for computer editing and display. Scanners come in hand-held, feed-in, and
flatbed types and for scanning black-and-white only, or color. Very high resolution scanners can
be used if you need to print scanned image in high-resolution, but lower resolution scanners are
adequate for capturing images for computer display. Scanners usually come with software, such
as Adobe’s Photoshop product, that lets you resize and otherwise modify a captured image.
Drum Scanner, Flatbed Scanner and Hand Scanner are the three different types of
scanners.
When it became possible to scan the images and pre-printed pages, the recognition
technology emerged that can recognize the text and marks present on the scanned image and
convert them into editable form. As per our syllabus we need to learn about OCR, OMR, BCR
and MICR scanners. Following are different technology on the topic:
OMR Technology
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Different marks OMR can read
The OMR technology allows user to read the check boxes – that is the sign affixed in predefined
spaces. This technology can be extremely useful to automate the marking of exam papers of
objective exams. Specialized software along with OMR can completely automate the checking,
marking and tabulating the exam papers.
ICR Technology
Handwritten text that ICR can recognize
With ICR technology it is possible to recognize manuscript data in unconstrained or constrained
mode when there is usually space among characters. It can be used to entry the forms directly
into the computer.
BCR Technology
Bar codes that BCR can read
The BCR technology allows the recognition of bar codes printed on retail products, as well as,
decoding their content.
OCR Technology
It’s the recognition technology for printed and typed texts. When you have any printed page and
require it to edit on computer, this technology can be used to input the document into computer
and create editable file.
OCR-A Technology
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This technology works on pre-printed OCR-A code lines of postal and banking documents;
OCR-B Technology
This technology works on pre-printed OCR-B code lines of postal and banking documents;
MICR CMC7 – E13B Technology
MICR technology can be used to identify the text written by magnetic ink. Magnetic ink is a
special type of ink that contains iron particles dissolved in ink. MICR magnetizes the writing and
scan it accurately. It can be used to verify the signatures in bank checks.
MICR CMC7-E13B Technology works on pre-printed CMC7 or E13B check code lines.
CHR Technology
It allows user to read manuscript data in cursive written (natural writing not in capital letters):
what was only imaginary a few years ago, now it’s real. This feature is essential for reading
forms that haven’t been expressly designed for the automatic acquisition and contain
unconstrained fields, freely written, without any tie.
Output Devices – Monitor, Printer and Plotters
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Output Unit Devices
A unit of computer system that sends information out of the computer or the unit of computer
system that provides the result of processing to the users is output unit. This unit receives
information from CPU and converts into suitable human readable form. Monitor, Plotter, Printer,
Projector, Speaker etc. are the output devices.
An output device is any peripheral device that converts machine-readable information into
people-readable form such as a monitor, printer, plotter and voice output device.
Monitors
A computer monitor is also called display screen or video display terminal (VDT). Text and
Images are displayed on monitors by individual dots called pixels. A pixel is the tiny blinking
material on computer screen that can be turned on and off or made different shades. A pixel is
the smallest unit on the screen. The density of dots determines the clarity of the images – known
as resolution. A screen resolution 1024 x 768 means that it has 1024 dots in one line and 768
lines in one screen. Another measure of display resolution is a dot pitch.
Computer display can be interlaced or non-interlaced. In case of interlaced technology, it
refreshes all odd lines on screen first then all even lines next. Non-interlaced technology
refreshes all the lines on the screen from top to bottom. So, the non-interlaced method gives
more stable video display and better for eyes but requires twice as much signal information as
interlaced.
There are two types of monitors – cathode-ray tubes (CRT) and flat panel display.
Cathode Ray Tube (CRT) Monitors
A cathode ray tube (CRT) is a specialized vacuumtube in which images are produced when an
electron beam strikes aphosphorescent surface. Most desktop computer displays make useof
CRTs. The CRT in a computer display is similar to the”picture tube” in a television receiver.
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CRT monitors are of two types – monochrome and color.
Monochrome Monitors
Monochrome monitors have only two colors – one for background and other for the foreground
(text). The colors can be white, amber or green on a dark background. While somewhat plain, the
use of a single phosphor to generate the single color in each pixel makes it possible for the
monitor to provide a very clear and crisp looking display.
A monochrome monitor was very common in the early days of computing, from the 1960s
through the 1980s until color monitors became popular. They are still widely used in applications
such as computerized cash register systems.
Color Monitors
A color monitor is a display peripheral that displays more than two colors. Color monitors
implement the RGB color model by using three different phosphors that appear red, green,
and blue when activated. By placing the phosphors directly next to each other, and activating
them with different intensities, color monitors can create an unlimited number of colors.Color
monitors have been developed through following paths:
CGA
CGA stands for Color Graphics Adapter. It is a circuit board introduced by IBM and the first
graphics standard for the IBM PC. With a CGA monitor, it is harder to read than with a
monochrome monitor because the CGA supports much fewer pixels. It supports 4 colors.
EGA:
It stands for Enhanced Graphics Adapter. EGA is a video display standard that has a resolution
of 640 by 350 pixels and supports 16 colors. EGA supports previous display modes and requires
a new monitor.
VGA:
VGA stands for Video Graphics Array. This is a video display standard that provides medium to
high resolution. In a text mode, the resolution of this board is 720 by 400 pixels. It supports 16
colors with a higher resolution of 640 by 480 pixels and 256 colors with 320 x 200 pixels.
Super VGA:
This is a very high resolution standard that displays up to 65,536 colors. Super VGA can support
a 16.8 million colors at 800 by 600 pixels and 256 colors at 1024 by 768 pixels. A high-priced
super VGA allows 1280 by 1024 pixels. Larger monitors (17″ or 21″ and larger) with a high
resolution of 1600 by 1280 pixels are available. VESA (Video Electronics Standards Association)
has set a standard for super VGA.
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Flat Panel Displays
Flat panel display LCD Monitor
Portable computers such as a lap top use flat panel displays, because they are more compact and
consume less power than CRTs. Portable computers use several kinds of flat panel screens:
Liquid-Crystal Displays (LCDs)
LCD is a display technology that creates characters by means of reflected light and is commonly
used in digital watches and laptop computers. LCDs replaced LEDs (light emitting diodes)
because LCDs use less power. LCDs are difficult to read in a strong light, because they do not
emit their own light. Portable computers wanted to have brighter and easier to read
displays. Backlit LCDs are used for the purpose now.
Backlit LCDs:
This is a type of LCD display having its own light source provided from the back of the screen.
The backlit makes the background brighter and clear, as a result the texts and images appear
sharper. However, this still is much less clear than CRTs. Thus, better technology is needed.
Active Matrix LCDs:
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This is an LCD display technique in which every dot on the screen has a transistor to control it
more accurately. This uses a transistor for each monochrome or each red, green and blue dot. It
provides better contrast, speeds up screen refresh and reduces motion smearing.
Electroluminescent (EL) Displays
A flat panel display technology that actively emits light at each pixel when it is electronic
charged. This provides a sharp, clear image and wide viewing angle. The EL display type of flat
panel is better than LCD.
Gas Plasma Displays
This is also called a gas panel or a plasma panel and is another flat screen technology. A plasma
panel contains a grid of electrodes in a flat, gas filled panel. The image can persist for a long
time without refreshing in this panel. The disadvantages of the gas plasma displays are that they
must use AC power and cannot show sharp contrast.
Printers
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Color Printers
Different types of printers
A printer is an output device that produces a hard copy of data on to a paper. The resolution of
printer output is expressed as DPI (Dots per inch).
Printers can be classified into different types in several ways. There are three types of printers
based on the way they print:
Serial Printers
Serial printers are also called a character printer. These printers print a single character at a time.
They are usually inexpensive and slow.
Line Printers
Line printers can print one line at a time. They are expensive and very fast. Line printers use a
band, a chain, etc.
Page Printers
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Page printers can print one whole page at a time. Page printers are also called a laser printer
because they usually use a laser to produce page images. The print quality of these printers is the
best though it is a little bit expensive. The price of the personal laser printer is decreasing
gradually.
Similarly, there are two types of printers based on the use of a hammer.
Impact Printers
Impact printers use a hammer or pin to hit the carbon ribbon. This forms characters or dots to
print images on the paper. Because these printers hit the paper it produces sound and thus they
are noisy. Dot-matrix and daisy-wheel printers are the examples of Impact Printers.
Nonimpact Printers
Non-impact printers do not touch paper to produce printout. They do not have the hammer and
do not hit. The examples of non-impact printer are ink-jet, laser printer, thermal printers and so
on.
There are two types of printers based on how they form characters.
Bit-Mapped Printers
Images are formed from groups of dots and can be placed anywhere on the page. They have
many printing options and good printing quality. They use PostScript as a standard language for
instructing a microcomputer.
Character-based Printers
These printers print characters into the lines and columns of a page. These printers use
predefined set of characters and are restricted in position of characters.
Microcomputers use five kinds of printers. They are daisy wheel printers, chain printers, dotmatrix printers, ink-jet printers, and laser printers.
Daisy-Wheel Printer
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Daisy Wheel Printer
Daisy-Wheel is a printer mechanism that uses any kind of hub (wheel) having a set of spokes at
the margin of the hub. The end of each spoke is a raised image of a type character. When the
wheel is turned and the required character is aligned to the print hammer, the character is then
struck into a ribbon and onto a paper with the hammer. The wheel can be removed to use a
different character set. Daisy-Wheel Printer prints typewriter-like very high quality characters.
However, they are slower and less reliable than dot-matrix printers. Microcomputer users seldom
use this printer, because the better dot-matrix printers and inexpensive laser printers are available
today.
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Daisy Wheel
Chain Printer
A chain printer uses a printing mechanism that uses character typefaces linked together in a
chain. The chain spins horizontally around a set of hammers aligned with each position. When
the required character is in front of the selected print position, hammer in that position hits the
paper into the ribbon against the character in the chain. This printer is not commonly found
around microcomputers, because it is a very expensive, high-speed machine designed originally
for mainframes and minicomputers. Chain printers are very reliable and can speed up to 3000
lines per minute.
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Chain Printer Mechanism
Dot-Matrix Printer
Dot-matrix printers are printers that write characters and form graphic images using one or two
columns of tiny dots on a print head. The dot hammer moving serially across the paper strikes an
inked-ribbon and creates images on paper.Dot matrix printers are popular printers used with
microcomputers, because the printers are highly reliable and inexpensive. They are used for tasks
where a high-quality image is not essential. Many users, however, move from dot printers to
laser printers, because the price of laser printers is falling down. Several kinds of dot matrix
printers are available with print heads that have 7, 9, 18, or 24 pins.
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Dot Matrix Printer
Ink-Jet Printer
Ink-jet is a printer mechanism that sprays one or more color of ink at high speed onto the paper
and produces high-quality printing. This printer also produces color printing as well as highquality image. That is, ink-jet printers can be used for variety of color printing at a relatively low
cost. Ink-jet printing has two methods: Continuous stream method and drop-on- demand method.
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Inkjet Printer
Laser Printer
A laser printer is a printer that uses the electrophotograpic method used in a copy machine. The
printer uses a laser beam light source to create images on a photographic drum. Then the images
on the drum are treated with a magnetically charged toner and then are transferred onto a paper.
A heat source is usually applied to make the images adhere.
In 1984, Hewlett-Packard introduced the first desktop laser printer, called the LaserJet. The laser
printer revolutionized personal computer printing and has spawned desktop publishing.
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Laser Printer
The laser printer produces high-resolution letters and graphics quality images, so it is adopted in
applications requiring high-quality output. Although a high-priced color laser printer is also
available in the market, a less expensive, desktop gray scale laser printer is widely used.
Recently, the laser printer is gaining its market share dramatically, mainly because the lowered
price and the quality.
Plotters
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Plotter
A plotter is a special-purpose output device that draws images with ink pens. That is, the plotter
is a graphics printer for making sophisticated graphs, charts, maps, and three-dimensional
graphics as well as high-quality colored documents. It can also produce larger size of documents.
Plotters require data in a vector graphics format that can produce images with a series of lines.
There are two main types of plotters:
Drum Plotter:
This is a plotter that has a drum. A paper wraps the drum that rotates to produce plots. Pens in a
drum plotter move across the paper while the drum is turning. A drum plotter is usually used to
produce smaller drawings.
Flatbed Plotter:
This is a plotter that has a bed. This is also called a table plotter. The plotter draws graphics on
the paper placed on the bed. There are several size of beds. This plotter is usually used for
producing large drawings.
System Unit Devices – Motherboard, Processor and Memory
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System Unit
System Unit is the main part of a microcomputer consisting processing unit and devices. A
system unit includes a motherboard that holds a microprocessor chip (which is the CPU),
memory chips, and expansion slots. The board contains printed electronic circuitry which
connects microprocessor with primary storage and other parts. The system unit is housed within
the system cabinet known as chassis.
A system unit includes the parts such as Motherboard, Microprocessor, Memory Chips, System
Clock, Buses, Ports, Expansion Slots and Cards
Motherboard
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Motherboard
A Motherboard or system board is the main circuit board of a microcomputer. It contains the
circuitry printed on a flat board. Motherboard connects microprocessor to all other parts of
computer and devices attached. Microprocessors, memory modules, BIOS chip and other ROM
chips, system clock, display adapters, build-in VGA and NIC, AGP and PCI expansion slots and
so on are housed on motherboard.
The expansion slots or sockets in motherboard accept additional expansion Cards often known as
daughterboard. In a microcomputer, the motherboard contains the processor, the primary storage
chips (or main memory cards), the buses, and all the chips used for controlling the peripheral
devices.
Microprocessor
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Microprocessor
A microprocessor is the main component of a microcomputer. It is a processor whose elements
are miniaturized into one or a few integrated circuits contained in a single silicon microchip.
Microprocessor executes instructions. In a microcomputer, it is a single microchip to hold the
central processing unit (CPU). To function as a processor, it requires a system clock, primary
storage, and power supply.
Several important lines of PCs use some families of microprocessor chips. Intel and Motorola are
the major companies that produce important microprocessors for IBM compatible and Macintosh
computers.
Microprocessor Capacity
The capacity of a microprocessor chip is represented in word sizes. A word size is the number of
bits (e.g., 8, 16, or 32 bits) that a computer (CPU) can process at a time.
If word has more bits, the computer (CPU) is more powerful and faster. For example, a 16-bitword computer can access 2 bytes (1 byte = 8 bits) at a time, while a 32-bit-word computer can
access 4 bytes at a time. Therefore, the 32-bit computer is faster than the 16-bit computer.
Based on computer architecture, there are two types of microprocessors – RISC and CISC.
CISC Chips:
CISC stands for Complex Instruction Set Computer. It is pronounced “sisk.” CISC is a computer
architecture that has large sets of instructions (micro-codes). CISC machines have several
hundred instructions. Intel’s Pentium-chip uses CISC design.
RISC Chip:
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RISC stands for Reduced Instruction Set Computer. RISC is a microprocessor that executes a few
number of instructions (micro-codes). This architecture has a small number of instructions built
into the circuits and if those basic instructions are made to execute faster, then RISC computers
increase performance. Although RISC machines are only around 30% faster than their CISC
machines, RISC chips are less expensive to produce. That is, RISC is less expensive per MIPS.
CONTROVERSY: The proponents of RISC claim that its lower cost and speed are an extreme
advantage, while the opponents claim its improvements are not great. The opponents believe that
new machine languages and greater performance improvements are going to come. Besides, the
reduced instructions make software (e.g., compilers) generate more code to do. Thus, the choice
is not obvious.
CPU Models
IBM and IBM Compatibles
Model NO.
Word Size CPU SPEED (MHz) BUS SIZE (Bits)
8088
16 bits
5-10
8
8086
16 bits
6-12
16
80286
16 bits
6-16
16
80386DX
32 bits
16-40
32
80386SX
32 bits
16-25
16
80486DX
32 bits
25-66
32
80486SX
32 bits
16-25
32
Pentium
32 bits
60-166
32-64
Pentium Pro
23 bits
150-231
32-64
Macintosh
CPU NO. (Word Size in Bits) CPU SPEED (MHz) BUS SIZE (Bits)
68000 (32)
8
16
68020 (32)
16
32
68030 (32)
16-40
32
68040 (32)
1
32
601( )
1
1
604( )
1
1
[Source: The University of Mississippi – www.olemiss.edu ]
Memory Chips
Primary memory is built into chips that can hold programs and data either temporarily or
permanently. Based on whether they can store data temporarily or permanently, there are two
types of memory chips – RAMs and ROMs.
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RAM Chips
RAM Chip
RAM stands for random-access memory. Random- access memory holds the data or instructions
that the CPU is presently processing. It is a volatile memory chip meaning the data stored in
RAM are temporary. It is erased automatically after some time or when the power supply is cut
off. A collection of RAM chips builds primary storage.
Types of RAM
I’ve presented a complete list of RAMs below. Please pay special attention to SRAM and
DRAM.
SRAM: Static random access memory can hold data as long as power supply is provided. It uses
multiple transistors, typically four to six, for each memory cell but doesn’t have a capacitor in
each cell. It is used primarily for cache.
DRAM: Dynamic random access memory can hold data only for few milliseconds. So it must be
refreshed periodically. It has memory cells with a paired transistor and capacitor.
FPM DRAM: Fast page mode dynamic random access memory was the original form of
DRAM. It waits through the entire process of locating a bit of data by column and row and then
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reading the bit before it starts on the next bit. Maximum transfer rate to L2 cache is
approximately 176 MBps.
EDO DRAM: Extended data-out dynamic random access memory does not wait for all of the
processing of the first bit before continuing to the next one. As soon as the address of the first bit
is located, EDO DRAM begins looking for the next bit. It is about five percent faster than FPM.
Maximum transfer rate to L2 cache is approximately 264 MBps.
SDRAM: Synchronous dynamic random access memory takes advantage of the burst mode
concept to greatly improve performance. It does this by staying on the row containing the
requested bit and moving rapidly through the columns, reading each bit as it goes. The idea is
that most of the time the data needed by the CPU will be in sequence. SDRAM is about five
percent faster than EDO RAM and is the most common form in desktops today. Maximum
transfer rate to L2 cache is approximately 528 MBps.
DDR SDRAM: Double data rate synchronous dynamic RAM is just like SDRAM except that is
has higher bandwidth, meaning greater speed. Maximum transfer rate to L2 cache is
approximately 1,064 MBps (for DDR SDRAM 133 MHZ).
RDRAM: Rambus dynamic random access memory is a radical departure from the previous
DRAM architecture. Designed by Rambus, RDRAM uses a Rambus in-line memory module
(RIMM), which is similar in size and pin configuration to a standard DIMM. What makes
RDRAM so different is its use of a special high-speed data bus called the Rambus channel.
RDRAM memory chips work in parallel to achieve a data rate of 800 MHz, or 1,600 MBps.
Since they operate at such high speeds, they generate much more heat than other types of chips.
To help dissipate the excess heat Rambus chips are fitted with a heat spreader, which looks like a
long thin wafer. Just like there are smaller versions of DIMMs, there are also SO-RIMMs,
designed for notebook computers.
Credit Card Memory: Credit card memory is a proprietary self-contained DRAM memory
module that plugs into a special slot for use in notebook computers.
PCMCIA Memory Card: Another self-contained DRAM module for notebooks, cards of this
type are not proprietary and should work with any notebook computer whose system bus
matches the memory card’s configuration.
CMOS RAM: CMOS RAM is a term for the small amount of memory used by your computer
and some other devices to remember things like hard disk settings. This memory uses a small
battery to provide it with the power it needs to maintain the memory contents.
VRAM: VideoRAM, also known as multiport dynamic random access memory(MPDRAM),is
a type of RAM used specifically for video adapters or 3-D accelerators. The “multiport” part
comes from the fact that VRAM normally has two independent access ports instead of one,
allowing the CPU and graphics processor to access the RAM simultaneously. VRAM is located
on the graphics card and comes in a variety of formats, many of which are proprietary. The
amount of VRAM is a determining factor in theresolution and color depth of the display. VRAM
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is also used to hold graphics-specific information such as3-D geometry data and texture maps.
True multiport VRAM tends to be expensive, so today, many graphics cards
use SGRAM (synchronous graphics RAM) instead. Performance is nearly the same, but
SGRAM is cheaper.
[source: How Stuff Work – computer.howstuffwork.com]
Memory Modules
Memory modules are the circuit board containing memory chips. The type of board and
connector used for RAM indesktop computers has evolved over the past few years. The first
types of memory modules were proprietary.
SIMM:stands for single in-line memory module. This memory board used a 30-pin connector
and was about 3.5 x .75 inches in size (about 9 x 2 cm). Later SIMM boards, slightly larger at
4.25 x 1 inch (about 11 x 2.5 cm), used a 72-pin connector for increased bandwidth and allowed
for up to 256 MB of RAM.
DIMM:As processors grew in speed and bandwidth capability, dual in-line memory
module (DIMM) evolved. With a whopping 168-pin or 184-pin connector and a size of 5.4 x 1
inch (about 14 x 2.5 cm), DIMMs range in capacity from 8 MB to 1 GB per module and can be
installed singly instead of in pairs.
RIMM:Another standard, Rambus in-line memory module(RIMM), is comparable in size and pin
configuration to DIMM but uses a special memory bus to greatly increase speed.
SODIMM:Many brands of notebook computers use proprietary memory modules, but several
manufacturers use RAM based on the small outline dual in-line memory module (SODIMM)
configuration. SODIMM cards are small, about 2 x 1 inch (5 x 2.5 cm), and have 144 or 200
pins. Capacity ranges from 16 MB to 1 GB per module. To conserve space, the Apple iMac
desktop computer uses SODIMMs instead of the traditional DIMMs.
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Sub-notebook computers use even smaller DIMMs, known as MicroDIMMs, which have either
144 pins or 172 pins.
Most memory available today is highly reliable. Most systems simply have the memory
controller check for errors at start-up and rely on that. Memory chips with built-in error-checking
typically use a method known as parity to check for errors. Parity chips have an extra bit for
every 8 bits of data.
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The majority of computers sold today use nonparity memory chips. These chips do not provide
any type of built-in error checking, but instead rely on the memory controller for error detection.
[Source: How Stuff Works – computer.howstuffworks.com]
ROM Chips
ROM Chip
ROM stands for read-only memory. A ROM chip is a memory chip that stores instructions and
data permanently. Its contents are placed into the ROM chip at the time of manufacture and
cannot be modified by the user. A CPU can read and retrieve the instructions and data from the
ROM chip, but it cannot change the contents in ROM.
ROM chips usually contain special instructions for computer operations such as ROM BIOS.
The variations on the ROM chip are the following:
PROM (Programmable Read-Only Memory):
A permanent storage device that becomes a read-only memory after it is written once by the
customer rather than by the chip manufacturer. For example, a software producer can write
instructions onto the PROM using special equipment.
EPROM (Erasable Programmable Read-Only Memory):
EPROM is a reusable PROM-chip that can be erased by a special ultraviolet light. EPROM holds
its content until erased and new instructions can be written on it.
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EEPROM (Electrically Erasable Programmable Read-Only Memory):
EEPROM-chip can be erased, either within a computer or externally, by electric power. The
process usually requires more voltage than the common +5 volts used in logic circuits.
EAPROM (Electrically Alterable Programmable Read-Only Memory)
EAPROM is another type of PROM stands for electrically alterable programmable read-only
memory. This type of memory can be changed by the computer using special high-current
operations. Programming these devices repeatedly (more than 1,000 times) tends to destroy
them, so they are used to hold data that rarely changes.
Primary Storage (Memory)
Primary storage (internal storage, main memory or memory) is the computer’s working storage
space that holds data, instructions for processing, and processed data (information) waiting to be
sent to secondary storage. Physically, primary storage is a collection of RAM chips.
The contents are held in primary storage only temporarily. Capacity varies with different
computers. Data or instructions are stored in primary storage locations called addresses.
Apart from motherboard, processor and memory, there are some other system unit devices worth
taking a note. I’ve tried to introduce each of those devices below:
System Clock
The clock is a device that generates periodic, accurately spaced signals. These signals are used
for several purposes such as regulation of the operations of a processor or generation of
interrupts. The clock circuit uses the fixed vibrations generated from a quartz crystal to deliver a
steady stream of pulses to the processor. The system clock controls the speed of all the operations
within a computer.
The clock speed is the internal speed of a computer. The clock speed is expressed
in megahertzes (MHz). 33 MHz means 33 million cycles per second. A computer processor’s
speed is faster if it has higher clock speed. For example, a 100-Mhz processor is four times as
fast internally as the same processor running at 25MHz.
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Expansion Slots
PCI Expansion Slots
Expansion slots are receptacles inside a system unit that printed circuit boards (expansion
boards) are plugged into. Computer buyers need to look at the number of expansion slots when
they buy a computer, because the number of expansion slots decides future expansion. In
microcomputers, the expansion slots are directly connected to the bus.
Expansion Boards
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PCI Expansion Cards
Expansion boards are also called expansion cards, controller cards, plug-in boards,adapter
cards, or interface cards. Expansion boards are printed circuit boards that have many electronic
components including chips. They are plugged into expansion slots.
Expansion boards are connected to peripherals through ports located on the edge of expansion
boards. Expansion boards include memory expansion cards (e.g., SIMM), I/O controller cards
(e.g., SCSI Card), video display card, sound cards, communications cards, etc.
Expansion slots and expansion boards can be of two types – open architecture and closed
architecture
Open Architecture: This architecture is a system whose specifications are made public to
encourage third-party vendors to develop add-on products for it. Most microcomputers
adopt open architecture. They allow users to expand their systems using optional expansion
boards.
Closed Architecture: This is a system whose technical specifications are not made public. With
a machine that has closed architecture, users cannot easily add new peripherals.
Ports
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Ports
A port is an external connecting socket on the outer side of the system unit. This is a pathway
into and out of the computer. A port lets users plug in outside peripherals, such as monitors,
scanners and printers.
Serial Ports
Serial ports are external I/O connectors used to attach modems, scanners or other serial interface
devices to the computer. The typical serial ports use a 9-pin DB-9 or a 25-pin DB-25 connector.
Serial ports transmit bits one after another on a single communications line. Serial lines
frequently are used to link equipment that is not located close by.
Parallel Ports
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Parallel ports are external I/O connectors on a computer used to hook up printers or other parallel
interface devices. The parallel port uses a DB-25 connector. This port transmits several bits
simultaneously. Parallel lines move information faster than serial lines do.
Buses
A bus is a data pathway between several hardware components inside or outside a computer. It
not only connects the parts of the CPU to each other, but also links the CPU with other important
hardware. The other important hardware includes memory, a disk control unit, a terminal control
unit, a printer control unit, and a communications control unit. The capacity of a bus is expressed
as bits. A larger capacity bus is faster in data transfer. For example, a 32-bit bus is faster than an
8-bit bus.
There are three main architectures of Bus – ISA, MCA and EISA.
ISA (Industry Standard Architecture): ISA is pronounced i- suh. This is the original PC bus
architecture. It includes the 8-bit (PC, XT) and 16-bit (AT) buses in IBM personal computer
series and compatibles. Now, it refers specially to the 16-bit AT bus.
MCA (Micro Channel Architecture): A 32-bit bus used in IBM P/S 2 series and other IBM
models. This architecture allows multiprocessing that allows several processors to work
simultaneously. Micro channel architecture is not compatible with PC bus architecture.
EISA (Extended Industry Standard Architecture): EISA is pronounced eesa. This is a bus
standard for PCs that extends the AT bus (the ISA bus) architecture to a 32-bit bus. This
architecture also allows more than one CPU to share the bus. The purpose of EISA is to extend
and amend the old ISA standard, so that all existing AT expansion boards can work with an
EISA slot.
Local Buses
The performance of a microcomputer is often restrained by the relatively slow video cards and
other peripherals, which cannot keep up with today’s fast CPUs. A local bus reduces the
performance gap between the high-speed microprocessors and slower hard disks, video boards
and other peripherals.
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Storage Devices – Magnetic and Optical Disks
Storage Unit Devices
Computers have two different types of storage – primary (temporary) storage and secondary
(permanent) storage. Secondary storage means external storage. There are many different types
of secondary storage available on the markets today.This storage device includes a magnetic
disk, optical disk, magnetic tape and others.
Data is stored in disk in Tracks and Sectors:
Track: The disk surface is divided into several concentric circles called tracks. The thinner the
tracks, the more storage capacity of the disk. Data are recorded as tiny spots on these tracks.
These tracks are closed concentric circles, not a single spiral. Each track has the same number of
bits although the outer tracks are longer than the inner ones.
Sector: The circular tracks are further divided into wedge-shaped sections known as sectors. The
fields of data within a particular record are organized according to tracks and sectors on a disk.
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Track and Sector
There are two kinds of sectors for a disk -hard sectored disk & soft sectored. The hard sectored
disk identifies sectors with some physical marks on the disk, whereas the soft sectored disk
identifies sectors with sector identification contained in the recording tracks.
A format program places the sector identification on the disk. When a user buys a disk
manufactured without tracks and sectors in place (this kind of disk does not have “Formatted”
label on it), he or she must put the tracks and sectors using a format program.
Floppy Disks
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Floppy Disk
Floppy disks are removable, direct access storage media. Floppy disks are inserted into floppy
disk drive to read and write. Floppy disks are flat, circular pieces of Mylar plastic that rotate
within a jacket (protective cover).These are also
calledflexibledisks,floppies,Diskettesorsimplydisks.
Data and instructions are stored as forms of bits and bytes using theASCIIorEBCDICdatacoding
schemes. They are stored as electromagnetic charges on a disk surface. The first floppies were of
8” in diameter.However, the two most common disks are 5 1/4-inch (5.25″) and 3 1/2-inch
(3.5″). More efficient size, high storage capacity and sturdier design of a 3.5″ make it popular
storage medium for microcomputers till the CDs and pen drive were available.
Capacity
DS/DD (2S/2D) Disk: DS/DD means Double Sided Double Density. This is a floppy disk
recordedonboth of its sides (DS) and has twice the capacity of the prior format (DD). For the
IBM and IBM compatible PCs, DD/DS disk usually has 40 tracks on each side and each side
contains 9 sectors of 512 bytes each.
DS/DD5.25” disks: 360KB
DS/DD3.5” disks: 720 KB (PCs), 800 KB for Mac formats.
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DS/HD Disk: DS/HD means Double Sided High Density. An HD disk has increased storage
capacity usually with more tracks per square inch. For IBM and IBM compatible PCs, an HD
disk is usually formatted to have 80 tracks on each side. Each side then contains 18 sectors of
512 bytes each – double capacity of a DD disk.
DS/HD5.25” disks: 1.2MB
DS/HD 3.5” disks: 1.44 MB (PCs), 1.44 MB for Mac formats.
Floppy Drives
A floppy drive is a device used to read data from floppy disks and store data inside it. Floppy
drive grabs a disk at its center and spins it inside its plastic jacket. The drive is made up of a box
with a slot into which a user inserts a disk. The slot has a drive gate. This drive rotates the disk
with a motor inside the drive. Electronic read/write heads ”read” data from the disk and “write”
data to it while the disk rotates.
A microcomputer usually has internal floppy drives inside the computer cabinet, but it
sometimes has external floppy drive, a separate component outside the cabinet.
Hard Disks (Hard Drives)
A hard disk is a magnetic disk made of metal plates and covered with a magnetic recording
surface. Hard disks come in removable and fixed varieties that hold from several hundreds of
megabytes to several gigabytes. They are tightly sealed to prevent any foreign matter (dust,
moist) from getting inside which causes head crash.
Interface Type
A hard disk can be installed in a computer using IDE or SCSI.
IDE(Integrated Drive Electronics): An IDE interface has a disk drive that contains its own
controller electronics. The IDE interface is also called an AT and XT interface. IDE-ready
motherboards have a 40-pin socket that connects directly to an IDE drive eliminating the use of
an expansion slot.
SCSI (Small Computer System Interface): SCSI is an 8-bit-bus peripheral interface for up to
seven peripherals. The SCSI bus allows any two devices to communicate at one time (host to
peripheral, peripheral to peripheral). SCSI provides high-speed (4MB/sec.), parallel data transfer
and multiple peripheral connections while taking only one expansion slot.
Access time:
This is an average time taken to complete the transfer of data after the request instruction has
been enacted. Today’s fast hard drives have access times under 10 milliseconds (ms). Access
time is made up of the following four times.
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Seek Time: This is the time taken to move an access arm to a certain track on a disk after the
computer requests data. Seek time is one of the slowest action that make up most of the access
time.
Head Switching Time: The time taken for changing from one read/write head to another to read
from or write on another part on a disk.
Search Time: It is also called rotational delay timeor latency time. This is a time required for the
read/write head to locate particular position on a track.
Data Transfer Time: This is the time for data to be transferred from the disk to primary storage
or vice versa.
Different Forms of Hard Disks
Internal Hard Disk
Internal hard disk is made up of several metallic platters, a motor, an access arm and read-write
heads sealed inside a container.
An internal hard disk is looked like a part of a system unit inside a computer cabinet. There are
two sizes of drives (5.25″ and 3.5″ in a diameter). 3.5″ hard disks are faster because the access
arm travels shorter distances across the diameter of the disk.
Internal hard disks have advantages over flexible disks. They are high capacity and speed. The
disadvantage of internal hard disks orhardcards is that they have only a fixed amount of storage
and cannot be easily removed.
External Hard-Disk Drives: This is a drive that is not built into the system cabinet of
microcomputers. External hard disk drives are treated as peripherals. Using external hard disk
drives, we can expand the hard disk capacity when all available drive bays are occupied.
Hard Disk Cartridges: A cartridge is a removable storage module, so a hard disk cartridge
contains disks in the module. They can be removed from a dock easily and can give fast access
to large data. An internal or external dock is available.
In internal hard disks and external hard disk drives, the storage capacity is fixed, but in the hard
disk cartridge, the capacity limitation of storage does not exist. That is, a user may add more
cartridges any time.
Removable Drives with Cartridges: Today’s advanced technology allows a new form of
removable storage. The technology combines the function of the hard disk drive and the
convenience of the hard disk cartridge. This form consists of a removable drive and several
cartridges.
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The removable drive looks like an external floppy disk drive. And the cartridge resembles a
floppy disk and allows users to add 100 MB or 1 GB at a time. It allows an SCSI connection as
well as a parallel port connection. Its low cost is a big advantage.
Optical Disks
Optical Disks
More advanced technology created a new disk storage forms. Optical disk is a disk written and
read by laser beam. This optical disk has a great impact on today’s storage technology. Optical
disk does not spin, does not need to move access arms and read/write heads, because a laser
beam can be moved electronically. The capacity of the storage is considerably greater than their
magnetic disk counterparts, and optical disk storage may eventually replace all magnetic tape
and disk storage.
Then how do they work? To write data, a laser beam burns tiny cavities into the surface of a disk
to mark bits for data. To read the data, a laser beam scans these areas. There are three forms of
optical disks available:
CD-ROM: CD-ROM (compact disk read only memory) is an optical disk storage that contains
text, graphics and hi-fi stereo sound. CD-ROM is a 4.75-inch optical disk storage that can store
around 650 MB of data. CD-ROM disk is almost the same as the music CD, but uses different
forms of track for data. A CD- ROM drive can read music CD, but a CD player cannot read CDROM. CD-ROM is a read-only disk that cannot be written on or erased by the user. In CD- ROM
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standard, data (text or pictures) cannot be viewed with audio play simultaneously. CD-ROM
XA standard can do.
WORM: A WORM (write once, read many) disk is an optical disk that written on just once by
the user’s environment and then cannot be overwritten. A WORM disk is ideal for use as archive
because it can be read many times, but the data cannot be erased. The storage capacity of
WORM disk ranges from 400 MB to 6.4 GB.
Erasable Optical Disks: This is an optical disk that can be erased and written on repeatedly. An
erasable optical disk has a great deal of data capacity. It can store up to 4.6 GB. An erasable
optical disk functions like a magnetic disk and has huge capacity, so it will replace the magnetic
disk in the future.
Magnetic Tape
Magnetic Tape
A magnetic tape is a tape coated with a magnetic material on which data can be stored. This is a
sequential storage device that is usually used for a backup purpose. A magnetic tape is slower
than direct access storage such as disk, because it is sequential access storage. The biggest
advantage of magnetic tape is the cost. It is much less expensive than magnetic disk and optical
disk. An advanced tape backup technology (DAT) is available these days.
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Extra Dose!
Cache (Cache memory): A cache is a specially designed buffer storage used to improve
computer performance by reducing access time. It holds instructions and data that are likely to be
needed for next operation by the processor. The cache copies frequently accessed data and
instructions from primary storage (main memory) or secondary storage (disks).
Disk Cache: A disk cache is in a reserved segment of primary memory or in an extra memory on
the disk controller card. It contains a large block of frequently accessed data copied from a disk.
The data in a disk cache can be used to fulfill the following data requests from a processor in a
high speed. The disk cache lets the processor avoid a slow disk access.
Memory Cache: A memory cache is high-speed memory storage between memory and the CPU.
It is smaller and much faster than main memory (primary storage). The memory cache copies
blocks of instructions and data from the main memory so that execution and data updating are
performed in the higher-speed memory bank.
Points to Remember
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A computer system is an integration of different units which comprises of various
hardware components and software, firmware as well as humanware.
The tangible parts or the physical components of a computer are known as computer
hardware.
The input output devices that are not built into Chassis (CPU box or Main Machine Box)
but installed in the periphery of CPU and connected through wires or wireless technology
are known as peripheral devices. Keyboard, Mouse, Printers, Scanners and so on are
some examples of peripheral devices.
The storage devices such as floppy disks, hard disks, microfilm or microfiche, CD, DVD
and Blu-ray disks are called computer media.
Computer collects the data for processing through various input devices.
Computer keyword is the main input device used to input data and instruction into the
computer. Based on how the keys are placed, you can find QWERTY, Dvorak and
many other keyboard layouts.
Based on the technology and the number of keys in it, there are XT keyboards (83
keys), AT keyboards (84 keys), Enhanced keyboards (101 or more keys)
and Windows keyboards (with Start and popup key). Multimedia keyboard is a term
popularly used to mean a keyboard that has Play, Pause, Forward, Backward keys to play
music directly from keyboard. Please read
Computer Mouse is a small palm sized pointing device that controls the movement of a
cursor on the screen. A mouse can be used to select, move and issue different commands
in GUI interface.
A mouse can be with one button, two button and three or more button. The mouse with
wheel is convenient for scrolling pages.
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Trackball is a stationary pointing device that contains a movable ball rotated with a finger
or palm. It looks similar to a mouse but we don’t move trackball like a mouse rather,
move the ball in it.
Joystick is a popular input device for playing computer games and it is also used in
computer aided designing (CAD). It looks like a car gear leaver and controls the
movement in screen.
Touch pad is a device for pointing on a computer display with finger. These are popular
alternative to mouse in Laptop and portable computers like personal digital assistants
(PDAs).
The first touch pad was invented by George E. Gerpheide in 1988.
Digitizer is a device that can be used to trace or copy a drawing or photograph. A special
stylus connected to computer is used to trace the item placed on flat digitizing tablet.
Light pen is a light sensitive penlike device used to point to displayed object and to draw
images on the screen.
Digital Camera is an electronic device that can be used to capture and store photographs
digitally instead of using photographic film like conventional camera. The images can be
read by a computer for further editing and modifications.
Webcam is a digital camera capable of downloading images to a computer for
transmission over the internet or other network. Webcams typically capture the images
as JPEG or MPEG files.
BCR (Bar Code Reader) is a photoelectric scanner that reads the bar codes, or vertical
zebra-striped marks printed on product containers. The data is coded into the lines with
different thickness and spaces to form bar codes. Bar codes are extensively used
supermarkets for inventory control (stock or store management).
Image Scanner is a light-sensing device that transmit images and other printed
information into digital form to the computer so that they can be stored or further
processed.
There are 4 types of image scanners – flat-bed scanner, sheet-feed scanner, drum scanner
and hand held scanner.
Smart Card Reader is an electronic device that reads smart cards. Smart card is a pocket
sized card with an integrated circuit (IC) in it. These cards are used as ID cards, payment
cards, public transit card, insurance card, SIM cards etc.
Microphone is an input device that capture the voice and sound and sends to the
computer to store or further processing.
Computer generated information is presented to the users through various output
devices.
Depending upon the nature of output computer produces, it can be hard copy output or
soft copy output. The temporary output such as sound played on speaker or image
displayed on monitor are soft-copy output. The printout from printer or plotter are hard
copy output.
Monitor is an example of VDU (visual display unit). It is a television like device that
displays the information generated by computer.
Three basic types of monitors in use these days are – CRT (cathode ray tube) and LCD
(liquid crystal display) and LED (Light Emitting Diode)
In CRT monitor, the images are formed when a beam of electrons hits the screen to light
up certain pixels to form the image on the monitor.
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In LCD monitor the images are formed when liquid crystal particles rearrange and light
up to form an image on the monitor.
In LED monitor A cluster of red, green, and blue diodes is driven together to form a
full-color pixel, usually square in shape. These pixels are spaced evenly apart and are
measured from center to center for absolute pixel resolution.
Digital Projector (digital projection display system) is a
specialized computer display that projects an enlarged image on a movie screen.
Speakers and Headphones are the voice output devices. They produce the sound received
from computer. A sound card in system unit is used to capture as well as play back the
recorded sounds.
A Printer is a hard copy output device that produces output in a permanent readable
form. Depending upon how a printer works, it may be impact printer or non-impact
printer.
In case of Impact Printers, the printing mechanism touches the paper to produce
characters or images such as in daisy wheel printer, dot matrix printer.
In case of non-impact printers, the printing is done without physically touching the paper.
These printers uses thermal, chemical, electrostatic, laser or inkjet technology to produce
printouts. So non-impact printers are less noisy compared to the impact printer.
Drum printer is an impact printer that consists of a solid cylindrical drum. The surface of
drum has raised characters in the form of bands. For each bands there is a hammer which
strikes the paper along with the inked ribbon to produce printout.
Dot matrix printers uses a movable print head consisting of pins which hits the inked
ribbon against paper to produce a dot on paper. The more pins in printing head the better
resolution it can offer. The speed of dot matrix is measured in cps (character per second)
Impact printers are better choice when you need to produce carbon copies of a printout.
Inkjet printer is a high quality non impact printer that forms characters by spraying small
drops of ink onto the paper. Inkjets are usually inexpensive, quite in operation ad produce
high quality output.
A laser printer uses non impact photocopier technology. When a document is sent to the
printer a laser beam draws the document on a selenium coated drum using electrical
charges. Then it is rolled in toner (dry ink power). The toner adheres the charged image
on the drum which is transferred to the paper and fused with heat and pressure.
A plotter is a specialized output device that produces high quality drawings, maps, charts
and other form of graphics. Unlike printers, a plotter can draw continuous point to point
lines directly from vector graphics files or commands.
There are different types of plotters available – drum plotter, flat bed plotter, electrostatic
plotter. Plotters are used for CAE (computer aided engineering), CAD (computer aided
design) and CAM (computer aided manufacturing).
Secondary memory supplements primary memory which is long term, non-volatile and
facilitates the storage of large volume of data. This memory is also called backing
memory or auxiliary memory or storage. Magnetic tapes, magnetic disks, optical disks,
flash memory etc. are some examples of secondary memory.
Magnetic tapes are the cheapest computer media that have slow data access and supports
only sequential data storage and retrieval. Magnetic tapes are best suited for sequential
data and for large backup purpose.
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Magnetic disks are the most popular computer media that stores data in a circular disks.
Floppies, hard disks, zip disks, super disks are the examples of magnetic disks. Floppy
diskettes contain a plastic disk coated with metal oxide whereas in hard disk drive, there
are metal disks. Magnetic disks can support both sequential and direct access. They have
relatively faster data access than magnetic tapes.
The storage capacity of floppy disks is measured in megabytes (MB), hard disks
in gigabytes (GB).
A typical 3.5″ floppy disk holds 1.44 MB of data.
Floppies can be single sided or double sided. Similarly there are low density floppies
or high density floppy disks. The disk code DD or 2D is used to mean double sided
double density. HD or 2HD is used to mean double sided high density.
IBM introduced the first 8″ floppy disk in 1971 which could store 100KB data. Please
visit the following link to see all types of floppy disks and important points to remember
Floppy Disks Computer Data Storage oldcomputers.net
A zip drive is a type of removal disk storage that is capable of storing 100MB to 250 MB
data. The first zip drive system was introduced by Lomega.
Super disks is a storage technology developed by Imation corporation which very highdensity diskettes.
In magnetic disks the surface is magnetized to store data whereas in optical disks the
surface is burned so that it can be read using light reflection.
CDs, DVDs, Blu-Ray are some examples of optical disks.
Optical disks have longer media life than magnetic disks and are free from the corruption
due to the magnetic or powerful electric fields.
Compact disk (CD) is a small portable round medium made of molded polymer for
electronical recording, storing and playing back audio, video, text and other information
in digital form. A CD ROM drive uses a low power laser beam to read digitized data that
have been encoded onto an optical disk in the form of tiny pits.
A standard CD ROM can hold 700 MB data.
DVD (Digital Versatile Disk) is a high density optical disk. It was invented by Philips,
Sony, Toshiba and Time Warner in 1995.
A DVD ROM supports disks with capacities of 4.7 GB to 17 GB and access rates of 600
KBps to 1.3 MBps.
Pen Drive is a portable USB flash memory device that can be used to quickly transfer
audio, video and data files from one computer to another. A pen drive consists of a small
printed circuit board encased in a plastic or metal casing. Pen drives are also called
flash drive or thumb drive.
Memory stick is an electronic flash memory data storage device used for storing digital
information. It was launched by Sony in 1998.
A system unit is also called chasis.
Motherboard is a large flat circuit board covered with sockets and other electronic parts,
including a variety of chips. It acts as a data path allowing the various components to
communicate with one another. External devices such as keyboard, mouse and monitor
cannot communicate with teh system unit without the mother board. Mother board is also
called system board.
Microprocessor is the complex integrated circuit, containing millions
of miniaturized electronic components. A microprocessor consists of several different
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sections: ALU performs calculations and makes logical decisions; the registers stores
temporary information; control unit directs and co-ordinates the activities of the entire
computers; buses carry digital information throughout the chip and the computer; local
memory supports on-chip computation.
More complex microprocessors often contain cache memory to speed up access to
external data storage device.
An expansion port is any connector that passes data in and out of a computer or
peripheral device. They are sometimes called Jacks or Connectors.
Serial port, parallel port, accelerated graphics port (AGP), USB port, FireWire port are
some of the popularly used ports in a computer.
Serial ports are used to connect mouse, keyboard, modem and many other devices.
Parallel port are mostly used to connect printers.
AGP ports are used to connect monitors. They are able to support high speed graphics
and other video input compared to VGA port.
USB ports can be used to connect up to 127 different devices with a single connector.
FireWire ports are used to connect high speed printers and even video cameras to the
system unit.
An expansion slot is a long, narrow socket on the motherboard into which you can plug
an expansion card.
An expansion card is a small circuit board that provides a computer with the ability to
control a storage device, an I/O device. Expansion cards are also called expansion
board, controller cards, adapters or daughter board.
Graphics card is an expansion card to generate output images to display. Monitor is
connected with graphics card through VGA port.
MODEM card is an expansion card that lets you connect telephone line with computer.
Sound card is an expansion card that enables a computer to manipulate and output sound
Network card is an expansion card which enables computer to physically connect to a
local network.
Power supply box is inside system unit which is designed to convert AC 110 V or 230 V
power from main to different low voltage DC power outputs for the internal component
of computer.
Exhaust fan is a component of system unit responsible for producing a cooling effect
inside the power supply.
System clock is a chip that synchronizes the activities of all the parts of a computer. It
uses the quartz crystal. Higher the clock speed, the faster the computer. Clock speeds are
expressed in MHz or GHz.
System Bus is a set of wires that facilitate communication between different components
of motherboard.
Programming Software: This is one of the most commonly known and popularly used types of computer
software. These software come in the form of tools that assist a programmer in writing computer
programs. Computer programs are sets of logical instructions that make a computer system perform
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certain tasks. The tools that help programmers in instructing a computer system include text editors,
compilers and interpreters. Compilers translate source code written in a programming language into the
language which a computer understands (mostly the binary form). Compilers generate objects which are
combined and converted into executable programs through linkers. Debuggers are used to check code
for bugs and debug it. The source code is partially or completely simulated for the debugging tool to run
on it and remove bugs if any. Interpreters execute programs. They execute the source code or a
precompiled code or translate source code into an intermediate language before execution.
System Software: It helps in running computer hardware and the computer system. System software
refers to the operating systems; device drivers, servers, windowing systems and utilities. System
software helps an application programmer in abstracting away from hardware, memory and other
internal complexities of a computer. An operating system provides users with a platform to execute
high-level programs. Firmware and BIOS provide the means to operate hardware.
Application Software: It enables the end users to accomplish certain specific tasks. Business software,
databases and educational software are some forms of application software. Different word processors,
which are dedicated to specialized tasks to be performed by the user, are other examples of application
software.
Malware: Malware refers to any malicious software and is a broader category of software that are a
threat to computer security. Adware, spyware, computer viruses, worms, trojan horses and scareware
are malware. Computer viruses are malicious programs which replicate themselves and spread from one
computer to another over the network or the Internet. Computer worms do the same, the only
difference being that viruses need a host program to attach with and spread, while worms don't need to
attach themselves to programs. Trojans replicate themselves and steal information. Spyware can
monitor user activity on a computer and steal user information without their knowledge.
Adware: Adware is software with the means of which advertisements are played and downloaded to a
computer. Programmers design adware as their tool to generate revenue. They do extract user
information like the websites he visits frequently and the pages he likes. Advertisements that appear as
pop-ups on your screen are the result of adware programs tracking you. But adware is not harmful to
computer security or user privacy. The data it collects is only for the purpose of inviting user clicks on
advertisements.
There are some other types of computer software like inventory management software, ERP, utility
software, accounting software among others that find applications in specific information and data
management systems. Let's take a look at some of them.
Inventory Management Software: This type of software helps an organization in tracking its goods and
materials on the basis of quality as well as quantity. Warehouse inventory management functions
encompass the internal warehouse movements and storage. Inventory software helps a company in
organizing inventory and optimizing the flow of goods in the organization, thus leading to improved
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customer service.
Utility Software: Also known as service routine, utility software helps in the management of computer
hardware and application software. It performs a small range of tasks. Disk defragmenters, systems
utilities and virus scanners are some of the typical examples of utility software.
Data Backup and Recovery Software: An ideal data backup and recovery software provides
functionalities beyond simple copying of data files. This software often supports user needs of specifying
what is to be backed up and when. Backup and recovery software preserve the original organization of
files and allow an easy retrieval of the backed up data.
Hard drive
Alternatively referred to as a hard disk drive and abbreviated as HD or HDD, the hard drive is
the computer's main storage media device that permanently stores all data on the computer. The
hard drive was first introduced on September 13, 1956 and consists of one or more hard drive
platters inside of air sealed casing. Most computer hard drives are in an internal drive bay at the
front of the computer and connect to the motherboard using either ATA, SCSI, or a SATA cable
and power cable. Below, is an illustration of what the inside of a hard drive looks like for a
desktop and laptop hard drive.
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As can be seen in the above picture, the desktop hard drive has six components: the head
actuator, read/write actuator arm, read/write head, spindle, and platter. On the back of a hard
drive is a circuit board called the disk controller.
1.
A driver is a piece of software that allows Microsoft® Windows® (or another operating system) to
communicate with the hardware devices in your system. Devices such as video cards, sound cards,
and modems all require drivers to function correctly within Windows. Sometimes, Windows includes
drivers for devices, but generally drivers need to be downloaded and installed separately.
Examples of Drivers
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2.
When to Update the Driver?
Note:
Dell Support now has the ability to scan some Dell computers for Driver Updates.
On the Drivers and Download page, if you see Scan Your System for Updates click on it to scan your
system.
The device drivers and firmware on a computer should be updated for numerous reasons some of which
include:
Increased system performance
Patch security risks
Expanded compatibility
Additional features
To fix problems
As directed by a Dell article
However, if your computer is working fine and the driver is not listed as an Urgent or Recommended
download,
there may be no reason to update your drivers. Installing drivers unnecessarily can, in some rare cases,
create new problems. Review the Criticality information listed on the driver download page for more
information.
Looking for information about How to update your Dell computers Drivers? Click Here
3.
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How do I Determine the Components in my Computer?
You have two options on how to determine the components in the computer.
Option 1: Continue on to Section 4,use the Service Tag to get a concise list of
Drivers and Downloads specific for your system. As shown in Section 4, Step 2.
Option 2: If you just want the Component list and not the downloads,
please follow the instructions below:
1. Browse to the System Configuration Tool
2. Select the Original System Configurations tab
3. Enter your Service Tag, then click Continue. The list of components on your computer is displayed.
This list can be referenced to help you find out what components you will need drivers for.
4.
How to Download and Install a Driver?
Browse to the Drivers and Downloads page.
Under the Yes subheading enter your Service Tag to get a concise list of drivers for your specific
product model. Click
Submit
to continue.
Note:
If the Service Tag is not available, under the No subheading select from the following options:
Click the Automatically detect my Service Tag for me button and click
Continue
. This option will only work if you are using the Internet Explorer browser.
Or
Click the Choose from a list of all Dell products button and click
Continue
. Next Select your product type, then product line, and finally your computers model.
If you are using Download Manager, click here for download and installation instructions.
Note:
If you are wanting to install a printer driver, click here
Under Refine your results you can optionally select your desired operating system, and category
settings from the drop-down boxes.
Select the driver you want to download from categories listed on the download page. See Section 5 to
understand what's listed in each category.
Click the to see which drivers are available for download in each category.
Review the information on the page and take note of Installation Instructions and Important Information.
Note:
If you are using Download Manager to download files, click here
Click
Download
You may receive a warning and an option to run or save the file.
Note:
If you want to download multiple drivers, you can click Add To Download List.
Once you have added all the drivers you want to download click
Download
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below b>Download List
Click
Save
.
When the Save As window appears, designate a folder to save the file that is being downloaded and
click
Save
. The download progress window displays.
Make sure the checkbox next to Close this dialog box when download completes is unchecked.
When the download completes click Run or Allow.
Note:
The User Account Control window may appear, click Continue
A small window will appear with
Continue
and
Exit
buttons, click
Continue
.
In the Select the folder where you want to unzip the files to window, click
OK
.
If a message appears asking to create a folder, click
Yes
. If a message appears asking to overwrite the folder, click
Yes to All
.
In the All files were successfully unzipped window, click
OK
A new window will appear, follow the prompts that appear to finish the installation. br>
5.
Basic Categories of Drivers and Downloads
A. Applications
Applications are software downloads that Dell is providing for use with your system, including but not
limited to:
1.Dell Quickset Utility
2.Dell Webcam Manager
3.Roxio Creator
4.Dell Support Center
B. Audio
Audio drivers increase or enable functionality for sound, by enabling the speaker ports to transmit
sound.
Audio drivers can typically fix no sound issues and sound quality issues.
C. BIOS
The acronym BIOS stands for Basic Input/Output System. When the computer is first started, the BIOS
activates all of the hardware required by the computer to boot including:
1.Dell Quickset Utility
2.Dell Webcam Manager
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3.Roxio Creator
4.Dell Support Center
After the BIOS completes this process, it transfers control of the computer to the operating system.
Click Here to Watch a Video on Steps to Update Bios on Your Computer
D. Chipset
Audio drivers increase or enable functionality for sound, by enabling the speaker ports to transmit
sound.
Audio drivers can typically fix no sound issues and sound quality issues.
E. Communication
Communication drivers are for internal 56k modems and utilities used for dial-up connections as
well as Mobile Broadband drivers.
F. Diagnostics
Diagnostics are to help diagnose malfunctioning computer hardware.
To run an online diagnostic Dell recommends Dell PC Diagnostics.
Click Here to Watch a Video on Steps to Run Dell PC Diagnostics
G. Input Device Driver
Input Device Drivers are drivers for webcams, mice and keyboard.
H. Network
Audio drivers increase or enable functionality for sound, by enabling the speaker ports to transmit
sound.
Audio drivers can typically fix no sound issues and sound quality issues.
I. Removable Storage
CD/DVD Firmware increases or expands reading and burning functionality with media.
It can typically fix burning or reading issues with the drive.
J. Serial ATA
Hard drive utilities for storage management Pre-Operating System, and in the Operating System.
K. System Utilities
Dell System Software is a utility that provides critical updates and patches for your operating system.
It is necessary for correct operation of your Dell computer.
L. Video
Video Drivers can increase or enable display functionality.
Installation Requirements WHILE
NETWORKING
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PetaLinux is a full-source distribution, and also includes complete, standalone GCC compiler
toolchains for the supported CPU architectures.
For this reason, it requires approximately one gigabyte of disk storage.
Hardware Requirements
It is expected that PetaLinux development will be performed on a "workstation-class" PC.
Minimum recommended specifications are:



512 Mbyte RAM
Pentium 4 2GHz CPU clock or equivalent
5 Gbyte free HDD space
Smaller memory, or slower CPUs can be used, however time to build a complete PetaLinux
system will be negatively impacted.
It is also anticipated that the Xilinx ISE and EDK design/synthesis tools wil also be installed and
used on this workstation. Their run-time performance is greatly impacted by memory capacity
and CPU supported.
The following external peripherials are also required to support the development environment of
FPGA based embedded platform.




A Xilinx-supported JTAG configuration solution
A serial RS232 port or (USB to Serial dongle)
A parallel port - Depending on the JTAG configuration solution
A USB port - Depending on the JTAG configuration solution
Software Requirements
PetaLinux is designed to integrate with the Xilinx ISE and EDK design and synthesis tools. In
particular, the PetaLogix AutoConfig technology automates the process of configuring an
Embedded Linux system to match the hardware system design and specification.
While is is possible to use PetaLinux as a purely standalone software development environment,
for maximum value it is recommended that the Xilinx tools be installed on the same system as
PetaLinux.
The TFTP server should be installed on the host machine for serving build images to the
embedded system over the Ethernet connection. Although, this is not absolutely necessary but it
will significantly reduce the image download time.
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Computer Basics
Equipment (Hardware)
COMPUTER A machine that processes information and performs
computations.
Tower or
Desktop
CPU
Monitor
Screen
Disk Drive
The "box" or case that holds
the parts that make up a
computer: CPU, hard disk
drive, floppy drive, memory
chips, power supply, interface
cards, etc. Click here to learn
more.
Central Processing Unit, or "brains" of the computer
An output display device (looks
similar to a TV) in a computer
system. You see information
on the monitor's screen.
The viewing area on a monitor or the information or image
displayed.
A device that reads data from (input) or records data onto
a disk for storage (output).
Floppy
Floppy Drive
.
3-1/2" Floppy Disk
Hard Drive The main device that a computer uses to store
information. Most computers come with a hard drive,
called drive C, located inside the computer case.
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CD-ROM ROM means Read-Only-Memory - you can only "read"
information, not save.
A CD can store a large amount of data including
documents, photographs, software, and music (about 20
songs)
CD Drive
Compact Disk
CD-R
CD-RW
A CD-Recordable drive can put
A CD-ReWritable drive can
data onto a disk in just one
be written onto more than
session, and then is "closed" once - similar to a floppy
one "burn" only - you can't add
or hard disk.
to it after you create it.
DVD-ROM
Digital Video Disk - Read-Only
Memory
Used to store full-length
movies, large programs,
etc.
CD's, CD-R's, CD-RW's, and DVD's all look the same.
You must read the label to determine what type of media it is.
Both CD's and DVD's are optical storage media. Optical technology uses
a laser or light beam to process information.
USB Flash
Drive
Mouse
These can hold documents,
picures, and music. Some
flash drives are also MP3
players.
A hand-held input device you roll on your desk to point to
and select items on your screen. When you move the
mouse, the mouse pointer on the screen moves in the same
direction.
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Mouse
pointer
The little symbol on your screen that you move with your
mouse. You use the mouse pointer to point to and select
items on your screen. The mouse pointer changes shape,
depending on its location on your screen and the action you
are performing.
Left Mouse Button - usually use this button
Right Mouse Button - occasionally use this button for
"special" actions
Scroll Wheel - the mouse wheel may work differently from
program to program. and it may not work in some
programs. In most word processing programs, you can
rotate the wheel to move up or down the page, equivalent
to using the PAGE UP or PAGE DOWN keys on your
keyboard or to clicking the scroll bar. Due to various
problems it is best if you do not use the scroll wheel in
the computer lab.
Click
Double
Click
Drag
Press and quickly release the button on a mouse
Press and quickly release the mouse button twice.
Move objects or data around on the screen through the
use of a mouse. Keep the left mouse button pressed while
you move the mouse.
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Speakers
Headphones
Output device that produces
sound and music when
connected to the computer.
Speakers come in different
shapes and may even be in the
monitor's case.
Output device for listening
that is held over the ears by a
band worn on the head
Microphone
Input device in which sound
energy is changed into
electrical energy for the
sending or recording sound
(your voice).
Scanner
Input device that reads copy
as an image and digitally
records the image
Digital
Camera
Records and stores images as a
digital file, operates similarly
to a "normal" camera, but no
"film" is needed
Projector
Output device for displaying
onto a large surface
(projection screen) what
appears on the computer
monitor.
Printer
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A device that produces a paper copy of the information on
your screen. The printer on the left is an INK JET
PRINTER, and the other is a LASER PRINTER.
.
.
Hub
Hubs are devices that have many ports into which network
cables are plugged. A hub takes the signal from each
computer and sends it to all of the other computers
through the network. Hubs come in different sizes and
colors. The hub must be plugged in and turned on for the
network to work - be sure you see green lights
Modem
A device that allows computers to communicate with each
other over telephone lines (Internet). At school we do not
use modems, we have a direct connection to the Internet
called a T-1 line.
Keyboard
Input device - choose letters, symbols, and actions by
pressing keys
Key
Any of the buttons on a keyboard that the user presses to
input data (information) or to type commands
Escape
Usually pressed while you are working in a software
application to stop the current activity, back out of a menu
(or screen), or return to a previous screen.
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Enter
Backspace
Used to move the cursor to the beginning of a new line. It
may also be called the return key. In some applications,
pressing Enter tells the computer to stop waiting for more
input and begin processing. Notice the arrow symbol on the
Enter key; it is sometimes used in instructions and means
to press the enter key.
Moves the cursor one space to the left, erasing any
character that is in its path
Spacebar Moves the cursor one space to
(split
the right, leaving a small blank
spacebar)
white area (space) on the
screen.
shift
If the spacebar is "split",
the left "spacebar" acts
like the backspace key - it
erases the character to
the left of the cursor.
Does nothing by itself, but when pressed and held down
with another key it makes either a capital letter or the
upper character on a key. Pressing Shift with a letter key
when the CAPS LOCK key is "on" makes a lower case
letter.
caps lock Makes all letters uppercase without having to use the
shift key - it is best to only use this when you are going to
make many letters uppercase - don't use for just a few
capital letters
tab
Marked with two arrows, one pointing left, the other,
right. If pressed by itself, it moves the cursor to the
next tab on the right. When pressed with the Shift key,
it moves the cursor to the previous tab stop on the left.
alt
Does nothing by itself. When pressed with another key, it
performs a special function. For example, pressing Alt-F4
may quit a currently running program.
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ctrl
Does nothing by itself. When pressed with another key, it
performs a special function. For example, pressing Ctrl-S
may "save" a document.
Num Lock Typically "on" at start up. When "on", it changes the keys
on the numeric keyboard from cursor control arrows to
numbers arranged in a typical ten-key calculator keypad.
Delete
On our "Windows" computers (P) it erases the character
to the right of the cursor. Some people say it performs a
"forward erase". It operates differently on a MAC.
End
The key you press to move the cursor to the end of the
current line. Many programs also use keyboard shortcuts
such as Ctrl+End to move the cursor to the end of a
document.
Insert
Changes between insert mode and overstrike mode in word
processing programs. In insert mode, all characters typed
are placed at the cursor position (or to the right of the
insertion point). As you type, anything to the right of the
cursor moves to the right to make room for the new
typing. If insert mode is turned off, typing then
overwrites (erases) the old characters instead of putting
the new ones before the old ones. This is often called
overwrite mode. Most PC keyboards have an Ins or Insert
key that lets you switch back and forth between insert
and overwrite modes. Many word processing programs
display OVR in a status bar at the bottom when overwrite
mode is on.
Home
The key you press to move
the cursor to the beginning
of the current line. Many
programs also use
keyboard shortcuts such
as Ctrl+Home to move the
cursor to the beginning of
a document.
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PgDn
The function of this key is usually software specific.
Typically, it scrolls a document backward one screen or
one page.
PgUp
The function of this key is usually software specific.
Typically it scrolls a document forward one screen or one
page.
Arrows
4 keys that move the cursor in the direction the arrow
points
Function
Keys
(F1, F2
...)
Special keys that perform a number of important tasks.
Their exact functions are software dependent. F1 usually
is reserved for Help, while F10 frequently exits or quits
the program.
Print Screen It directs the computer to copy whatever is displayed on
the screen to the clipboard for pasting later. It doesn't
really "print" in Windows.
Scroll Lock
Its function is often software specific. In spreadsheets,
it usually locks the cursor on its current screen line and
scrolls text (rather than the cursor) up or down whenever
an up or down cursor control arrow is pressed.
Pause
Not usually used with Windows. Pressing this key under
DOS temporarily stops a screen display or freezes rapidly
scrolling information.
Windows Key The WINDOWS key acts as another special function key.
If you press the Window key by itself, the Start Menu
will open. Windows+E will launch Windows Explorer.
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To get started:
1. Install and run VMware Player.
2. Make sure you have your Windows XP installation CD ready.
3. Make sure you have created the virtual machine configuration file (.vmx) and a virtual
hard disk (.vmdk).
4. If you are installing for real (NOT in VMware Player), unplug the cable that connects to
the Internet until after you have finished setting the Windows up and configured a
firewall.
If I get lots of mails from people asking how to create the .vmx and .vmdk files, I will add a
paragraph about it.
To begin the installation:
1. Place the Windows XP installation CD in the CD-ROM tray.
2. Start the VMware Player and open the Windows XP .vmx file (e.g. named win_xp.vmx).
With the virtual PC booting, hit Esc button to enter the BIOS setup. Select option 3. CD-ROM
Drive. Hit Enter to start booting from CD.
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The virtual PC should start booting from the Windows XP disk now. If you have a SCSI hard
disk or you wish to install the operating system in a RAID configuration (use several hard disks
to boot the operating system), you might need to install special drivers. In reality, you would
press F6 at this stage. In virtual machine, we will skip this.
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You will now reach the Windows XP welcome-to-setup screen. You can choose to setup
Windows XP or repair an existing installation. Using the second option might be useful if your
Windows XP does not boot and you need to fix it. However, in our case, we want to start a clean
installation. To do so, press ENTER.
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It's time to agree to Microsoft terms of use. If you agree with what's written, press F8 to
continue.
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It's time to partition our virtual hard disk. An empty unwritten-on hard disk will contain no
information. It will be unpartitioned. To make it usable, we need to partition it.
If you're installing on a hard disk that was previously used, partitions WILL exist. You will need
to destroy one of the partitions to install the operating system. It will also cause the loss of data
on that partition. So make sure your personal, irreplaceable data has been safely backed up.
In case partitions exist, you will want to erase one or all partitions (no screenshot provided) and
then create new partitions. In case the disk is empty, you will just need to create new partitions.
If I get lots of emails from people asking how to delete existing partitions, I will make another
"simulation" and provide necessary screenshots.
In our case, we have a 6GB empty hard disk. We want to partition it. The unpartitioned space is
already selected (highlighted in white). In case there are several physical hard disks available, we
would see several lines of unpartitioned space information. We would then have to select
(highlight) one of them (using arrow keys).
As you can see, we have 3 options:
1. Setup Windows XP on a selected partition - press ENTER.
We do not have partitions ready yet.
2. Create a new partition in the unpartitioned space - press C.
This is what we want to do.
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3. Delete selected partitions - press D.
If there were partitions we wanted to delete, this is what we would do.
Again, our choice is to create a new partition. Press C.
Installing Windows XP - Part 2
After pressing C, we will now be given an option to choose the size for our partition. This is an
important step. This is where the user has to ask himself / herself what configuration he / she
might like?
Creating a single partition using all of the available space is the simplest choice. However, it is
not the best choice. We want to separate the system files from our personal data. We want to
create separate partitions for the two. Thus, if our system gets broken, we will be able to install it
again without touching the personal data.
Thus, we will not use all of the available space. We will create a partition for the operation
system and a partition for the personal data. We will create a 4GB partition for the operating
system. Windows XP needs about 1-2GB to install and run smoothly. You could probably get
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away with less and you can definitely get away with more. It all depends on the size of your hard
disk.
We want to use the 4GB partition to install Windows and later, in Windows, install programs.
This will be our primary partition when booted in Windows. It will also be the first partition on
our (first) hard disk.
Enter the desired size (in thousands of MB) and press Enter.
As you can see, we now have a partition ready, onto which we can install Windows XP. You can
proceed to the setup now. You do not have to partition the spare space now. But be aware that it
will not be usable until partitioned. Windows XP does not have a partitioning capability built-in.
Therefore, unless you use some third-party software, it is wise to do it right now.
This will be our logical non-bootable partition when booted in Windows. It will serve us for
personal data. It will also be the second partition on our (first) hard disk. Move the selection
(highlight) with arrow keys down to unpartitioned space. Press C again to create a new partition.
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Once again, we will be presented with the choice of the size. You can also see that 8MB will not
be accounted for no matter what. This is because the first sector of the hard disk cannot be used
to create partitions on it. It is reserved for the boot information which tells the system which
partition to use to boot from. This is also called Master Boot Record (MBR). This is the most
important sector on a hard disk.
We will use all of the available free space for our second partition. Theoretically, if you have a
very large hard disk, you could create several logical partitions. Or leave some space free for a
Linux installation. Enter the desired size (in thousands of MB) and press Enter.
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Now, our hard disk is ready for the installation. Select (highlight) the desired partition - it will be
the first one! - and press Enter to start the installation.
Newly created partition(s) will not be formatted. We need to format our selected partition to be
able to actually install the operation system on it. We will format the partition using the NTFS
file system. NTFS file system has an advantage over the FAT32 file system in its ability to
handle very large storage disks, in the fragmentation of files and overall security it offers.
Windows XP should be installed on a partition formatted with NTFS file system.
You should be aware that:
Windows 98 cannot read NTFS partitions. If you have Windows 98 installed in dual boot
alongside Windows XP, Windows 98 will not be able to see the NTFS partitions.
NTFS file system is a closed source and therefore cannot be written to from Linux operating
systems (without proper patches). This means that NTFS partitions will be accessible as readonly from Linux operating systems. But this should not worry you too much. For the time being,
we are only installing Windows XP.
Select to format using NTFS file system and press Enter. We will not do a quick format, even
though it saves time, because if the disk has had data previously written on it, it might not be
properly wiped away.
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Formatting will take some time, depending on the disk size. It can take several minutes. It's a
good time to make a cup of coffee.
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Installing Windows XP - Part 3
After the setup formats the partition, it will start copying system files. This will take several
minutes.
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After the files are successfully copied, the system will reboot. Do not be alarmed. You can wait a
few seconds or press Enter to speed up the process.
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After the reboot, the setup will start installing Windows. You will be able to move your mouse
(hopefully) and read on-screen tips while the setup configures the system. You will also be able
to tell the approximate time needed for the setup to complete.
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After some time, you will be presented with Regional and Language Options. Here, you can set
your additional languages and keyboard layouts to suit your local needs. In my setup, I used only
the standard settings. After you're satisfied with your choice, click Next to continue. If you feel
you missed something, you will always be able to go back by clicking Back. If enough people
mail me about this step, I will add a small guide.
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After the Regional and Language Options, the setup will ask you for your username. You can use
anything you like. For example, I called myself USER and I have no organization.
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The next step is to input your License Product Key. It should be included with your Windows XP
installation CD.
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Now, you need to setup your Computer name and the Administrator password. You can use
whatever computer name you feel like, but you can also leave the default selection. I suggest you
choose a strong password for the Administrator account; something like rdSa^tbrIw17.
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Installing Windows XP - Part 4
The next step is to set your local Date and Time. This is pretty straightforward, I dare say.
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After this step, the setup will continue to install for a few minutes. Once again, you will be able
to read on-screen tips about Windows XP (no screenshot provided). The next step will be to
configure your Networking settings. You can use the Typical settings, and they should work just
fine. However, I have chosen the Custom settings to show you what they look like.
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It is possible that you will not want one of the components to be installed. You can uncheck it at
this stage. Later on, you will be able to install it if you need it. You may also want to look more
deeply into what each component means and what it offers. Brief explanations are offered in the
Description field for each highlighted item. During the installation, by default, all of the options
are selected and you should leave them that way.
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The next step is to associate your computer with a workgroup. If your computer is a member of a
small household network that shares resources, you might want to give it a name of the
household workgroup. Again, you may change this setting later. If your machine is a standalone
workstation, you should not bother with the Workgroup name.
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The setup will now continue for some time.
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Eventually, after some time, the computer (virtual machine) will reboot and start loading the
Windows. That is what we want to see.
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Before the Welcome screen, if your graphic adapters are properly configured, like in the
particular case of this virtual machine, Windows will present you with a message that it adjusts
the screen resolution to a pre-defined optimized standard. You will be able to change this later
on.
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After changing the resolution, Windows will ask you to confirm it. Some monitors might not be
able to display the desired settings. For instance, a very old monitor might be limited to only
800x600 resolution. Trying to set a higher value will result in a black or flickering screen, and
you will not be able to confirm the adjustment. If within 30 seconds you do not confirm the
change, the display settings will be reverted to the basics (the one used during the installation).
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Installing Windows XP - Part 5
Finally, you will reach the Welcome screen. Click Next to continue.
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You will be asked about Automatic Updates. While some may tell you that automatic updates are
a good thing, I would disagree. What if an update is accidentally corrupted? It will automatically
be downloaded, without your control of the event. It is better to turn the Automatic Updates off,
frequently visit Windows Update for manual updates and use the web in general to get updated
about possible problems that other users worldwide might have with a certain patch. The
message that your computer is more vulnerable to viruses and other threats is alarming and not
necessarily true.
Of course, the choice is entirely up to you.
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After the Automatic Updates configuration, you will be asked about Internet Connections. If
your computer connects through a router or another PC, you will most probably want to choose
Local Area Network (LAN). In our case, the virtual machine is indeed a member of a network,
connecting to the Internet through our host machine. During a real installation, you might want
to choose the first option. You can also skip this step and do it later.
In general, I advise you to skip the process now. During this step, Windows will try to
communicate with the Internet. This is not a good idea. We have not fully configured our
operating system yet. For instance, we have no firewall except the default Windows XP inboundonly firewall active on the computer, and no anti-malware software of any kind. Furthermore, if
you use a VPN dialer to connect to the Internet, or have not yet configured a service with an
Internet Service Provider (ISP), this step will fail. It will not prevent any and all other steps from
getting completed, though.
Moreover, you can prevent Internet access by setting the Ethernet tab in the VMware Player to
"Host only", which will allow only the "real" operating system to connect to the Internet. Using
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"NAT" or "Bridged" will also allow your guest operating system to connect.
As a healthy rule, it is advisable to disconnect the Internet line from the wall while installing
Windows.
Now, you will be asked to register. Even if you want to do that, now is not the time. You can do
it later.
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The next stage is to define the computer users. Even if you intend to have more than one user
account on your PC, you should only configure one at this time. You can always add more users
later. I chose a name Thor because it sounds nice.
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You are set. It's time to log into Windows.
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After a few seconds, you will see the Windows desktop. Basically, the installation itself is
finished. Congratulations!
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The procedure should have taken you about 40-70 minutes, depending on your CPU power, the
memory and your own speed. You should definitely not hurry, but take time and study each step
carefully. Of course, our work is not fully done.
On the next page, I will explain some of basic configurations you can do to make your Windows
experience easier. Most of the stuff explained on the next page is optional.
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Installing Windows XP - Part 6
You have installed Windows. It's time to configure a number of other items.
Installation of drivers
Install your video drivers. Change your monitor refresh frequency and screen resolution to fit
your needs. Install your audio drivers. Make sure you have properly installed the drivers by
testing out some sample music track. Install your other drivers, for instance USB 2.0
drivers, printer, UPS etc. After you have successfully installed your environment, it's time for
some true geek time.
Tweaking
Windows XP ships out in a default configurations that is rather loose. It is meant to suit as many
people as possible at the same time, which is rather impossible. You can make some small yet
pretty powerful changes that will make the overall feel a whole lot smoother.
Please note that this guide is not meant to be a comprehensive Windows user guide. You can get
a pretty reasonable help by pressing F1. Furthermore, there's a wealth of information available
online.
Most of the instructions following will not be accompanied with screenshots. There are too many
of them, and it would get rather boring after a while. However, I will give you a basic overview
to help you get oriented, though most likely if you decided to read through this article AND
decided to install Windows XP from scratch in a VMware Player (or for real), the chances are
you most likely do not need a basic overview of the Windows XP functionality.
Taskbar
Taskbar is a field between the Start Menu and the System Tray and will show your active
applications as small bars. It can also serve to place shortcuts (as Quick Launch).
Start Menu
Start Menu gives access to all of the programs and applications installed on the computer.
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System Tray
System Tray is used to show small icons of programs loaded into memory and running.
Performance & annoyance tweaks
The below tweaks will improve visual performance, make the Windows look less flashy and free
hard disk space by reducing the unnecessarily large default storage certain functions take.
If you have doubt, do not do these steps without being sure how to revert them. Do not do these
steps if you do not understand what they mean. Like I said, this guide is not a step-by-step
Windows help. Use the Help and Internet to get fully acquainted with Windows. You can always
do these tweaks at a later time.
Windows XP Tour
Click on the Windows XP Tour icon in the System Tray.
When the Window XP Tour pops up, click Cancel and you will never be bothered again.
Disable Security Center alerts
Right click on the Security Center system tray icon > Open Security Center. On the left-hand
side, under Resources, click on the bottom option Change the way Security Center alerts me.
Untick the three options (firewall, anti-virus and automatic updates).
Changing Start Menu view to Classic
Right click on the Taskbar > Properties.
Under Taskbar options, tick Show Quick Launch.
Under Start Menu options, tick Classic Start menu.
Changing Windows display to Classic
Right click on the Desktop > Properties.
Under Themes, select Windows Classic theme.
Change Control Panel view
Start > Settings > Control Panel.
Switch to Classic View.
Resize the System Restore space
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Right click on My Computer > Properties.
Under System Restore settings, slide the bar to desired percentage.
Resize the Recycle Bin space
Right click on Recycle Bin > Properties.
Slide the bar to desired percentage.
Resize the Internet Explorer cache
Right click on Internet Explorer > Properties.
Under General > Temporary Internet files click Settings.
Select the cache size to no more than 50-100MB.
Format the remaining hard disk(s)
We have created a roughly 2GB size hard disk while partitioning. It's time to format it now and
make it usable. Double click My Computer. Select the hard disk (most likely local disk (D:),
certainly NOT local disk (C:)), right click > Format.
We want to use this hard disk for personal data. Therefore, we will format it as FAT32, because
we might like to be able to write to it from other operating systems, like Linux. Rename this disk
to DATA or something similar.
This is, of course, an optional step. You may or may not create additional partitions while
installing the system for real. It's up to you. I advise you to use partitions, as they improve
security and order.
Creating a Limited User Account (LUA)
Most people use their default administrator account. This is OK, if you know 100% what to do in
case of serious malware infection. Otherwise, setting up a limited account can be a good practice.
Regardless of whether your daily needs require that you use administrator account or a limited
account, it is recommended that you:




Password protect the default administrator account. To do this, boot into Safe Mode, log
in as the Administrator, head in to Start > Control Center > User Accounts. Password
protect the account with a strong password (something like acD221oOm23^K2W). We
have done that during the setup, but it does not hurt to check out. This can also be a good
practice to see what Safe Mode is and how it works. To boot into Safe Mode, press F8
during the boot up. This might not work in VMware Player.
Disable the Guest account, if it isn't already.
Delete the .ASP account, if it exists.
Reboot into normal mode and password protect your own account with a solid, strong
password.
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To create a limited account:
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

Access User Accounts (see above) and select Create a new account.
Select a name for your limited account.
Select the type for your limited account; naturally you want to selected Limited.
Create the new account.
Create a new account:
Name the new account:
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Select the account type to be limited:
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Once it is created, you can rename it if you like, change its icon and password protect it.
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To see what a Limited User account looks like, just log off as Thor (or whatever your name is)
and log in as Limited.
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As you can see, Limited is a new separate account and all previous changes we did no longer
apply. We will have to configure things again.
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Limited account should be indeed limited. How can we know Limited is restricted?
Let's try to access the Group Policy editor. Group Policy Editor (gpedit.msc) is a powerful tool
that allows any Windows administrator-type user to set global or user rules called Restriction
Policies. These policies can range from white-listing files that can be executed on the computer
to preventing the use of command line, prevent access to Control Panel and much more. It can
also be used in a very beneficial way to improve privacy and security. I will address that in
another article.
To start the Editor:
Start > Run > gpedit.msc
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Indeed, if we try to access the gpedit.msc, under a limited account we expect to receive an error
message.
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As expected, Limited is a limited account and thus cannot access gpedit.msc. In a way this is a
good thing. If you cannot access certain options, neither will virii, trojans and other types of
malware be able to do that. As a limited account user, you will not be able to install software.
Even if you inadvertently trigger a bad file on your desktop, it will not be able to propagate and
cause harm. Limited account is a good way of preventing the user himself from making serious
judgment mistakes in his day-to-day use. You should bear in mind that these restrictions could
impair functionality of certain programs. You will also have to log in as the administrator to
perform system updates, like anti-virus definition updates.
To run applications that require administrative privileges, you can try to use the Run as ... shell
option - right click on an application and select Run as ... Alternatively, you can use
DropMyRights to run software with reduced (limited) privileged under an administrator type
account. By the way, changing desktops in the administrator and limited account is a good idea.
It's your best visual indicator which account you're using.
Internet
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Create your first System Restore point; this will be your "reference" restore point, a clean system
installation. Configure your Internet connection now - if you're using direct connection, just plug
the line back into the socket. If you're using VPN dialers, call your ISP and ask them to help you
configure one.
Updates
Before installing Windows XP on a PC, I suggest you create a CD containing all your favorite
software, like firewall, anti-virus, java engine, browser, mail client, and more. That way, you will
not require an Internet connection to properly secure your PC. If you do not have your favorite
tools ready, do it like this then:







Open Internet Explorer once. Go to Mozilla Firefox site. Download and install Firefox.
Make it your default browser.
Head to the site of your favorite firewall vendor. If you do not have one, or want a free
solution, try ZoneAlarm Free. Install the firewall.
Head to the site of your favorite anti-virus vendor. If you do not have one, or want a free
solution, try AVG Free. Install the anti-virus. Perform a full update. If firewall prompts
you, allow it.
Now, perform Windows Update. Install the patches you want. Usually, you would like to
install most of the critical patches. But I do suggest you read carefully about each update
and decide whether you really need it. Since you may have the automatic updates turned
off, make this check at least once a month. Microsoft usually release updates on first
Tuesday every month.
You might want to use Java on your computer. You might want to try Sun Java.
You might want to use a mail client. I suggest you try Mozilla Thunderbird rather than
the default Outlook Express.
You might want to have an Office suite on your PC. Open Office is a great, free product.
General rules that can make your PC life easier
You might want to defragment your hard drive once a month or so to boost its performance.
Keep your private data separate from the operating system - on the second partition we created.
If you have a large hard disk, or better, several hard disks, do not hesitate to make even more
partitions. Back your data frequently across the system (partitions, hard disks, other computers)
and to hard copies (CDs, DVDs, USB drives).
Create a System Restore checkpoint before installing any software. That's it. Your computer is
pretty much setup. You have learned how to install Windows XP, create multiple partitions,
create a user account, all of that in less than two hours. It's time to lean back and relax. You
won't be needing those technicians any more. Who knows, you might even teach them a trick or
two?
Enjoy!
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How to install Windows XP
Most of users use windows XP operating system for computer system. But mostlypeople do not
know installation process for the windows XP. Most of computer comewith Windows XP. But If want to Install
Windows XP on your computer you can followthe steps of Installation Process Of XP.
Installation Process
Installing Windows XP can take up to two hours. To make the process moremanageable, it has been broken
up into several sections. When you are ready,install Windows XP:
Begin the Installtion
1.Insert the Windows XP CD into your computer and restart your computer.
2.If prompted to start from the CD, press SPACEBAR. If you miss the prompt (it onlyappears for a few
seconds), restart your computer to try again.
3.Windows XP Setup begins. During this portion of setup, your mouse will not work,so you must
use the keyboard. On the Welcome to Setup page, press ENTER.
4.On the Windows XP Licensing Agreement page, read the licensing agreement.Press the PAGE DOWN key to
scroll to the bottom of the agreement. Then press F8.
5.This page enables you to select the hard disk drive on which Windows XP will beinstalled. Once you
complete this step, all data on your hard disk drive will beremoved and cannot be recovered. It is
extremely important that you have a recentbackup copy of your files before continuing. When you have a backup
copy, press D,and then press L when prompted. This deletes your existing data.
6.Press ENTER to select Unpartitioned space, which appears by default.
7.Press ENTER again to select Format the partition using the NTFS file system, whichappears by default.
8.Windows XP erases your hard disk drive using a process called formatting andthen copies the setup files. You
can leave your computer and return in 20 to 30minutes.
Continue the installation
9.Windows XP restarts and then continues with the installation process. From thispoint forward, you can use your
mouse. Eventually, the Regional and LanguageOptions page appears. Click Next to accept the default
settings. If you aremultilingual or prefer a language other than English, you can change
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languagesettings after setup is complete.10.On the Personalize Your Software page, type your name and
your organizationname. Some programs use this information to automatically fill in your name whenrequired.
Then, click Next.11.On the Your Product Key page, type your product key as it appears on yourWindows XP CD
case. The product key is unique for every Windows XP installation. Then, click Next.
12.On the Computer Name and Administrator Password page, in the Computername box, type a name that
uniquely identifies your computer in your house, suchas FAMILYROOM or TOMS. You cannot use
spaces or punctuation. If you connect your
computer to a network, you will use this computer name to find shared files andprinters. Type a strong password
that you can remember in the Administratorpassword box, and then retype it in the Confirm password box. Write
the passworddown and store it in a secure place. Click Next.
13.On the Date and Time Settings page, set your computer’s clock. Then, click the Time Zone
down arrow, and select your time zone. Click Next.14.Windows XP will spend about a minute
configuring your computer. On theNetworking Settings page, click Next.15.On the Workgroup or
Computer Domain page, click Next.
Complete the installation
16.Windows XP will spend 20 or 30 minutes configuring your computer and willautomatically restart when
finished. When the Display Settings dialog appears, clickOK.17.When the Monitor Settings
dialog box appears, click OK.18.The final stage of setup begins. On the Welcome to Microsoft Windows
page,click Next.19.On the Help protect your PC page, click Help protect my PC by turning
onAutomatic Updates now. Then, click Next.2000.Windows XP will then check if you are connected
to the Internet:•If you are connected to the Internet, select the choice that describes your
networkconnection on the Will this computer connect to the Internet directly, or through anetwork? page. If
you’re not sure, accept the default selection, and click Next.•If you use dial-up Internet access, or
if Windows XP cannot connect to the Internet,you can connect to the Internet after setup is
complete. On the How will thiscomputer connect to the Internet? page, click Skip.21.Windows XP
Setup displays the Ready to activate Windows? page. If you areconnected to the Internet, click Yes, and then click
Next. If you are not yetconnected to the Internet, click No, click Next, and then skip to step 24. After
setupis complete, Windows XP will automatically remind you to activate and register yourcopy of
Windows XP.22.On the Ready to register with Microsoft? page, click Yes, and then click Next.23.On the
Collecting Registration Information page, complete the form. Then, clickNext.24.On the Who
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will use this computer? page, type the name of each person who willuse the computer. You can use
first names only, nicknames, or full names. Thenclick Next. To add users after setup is complete or to specify a
password to keepyour account private, read Create and customize user accounts.25.On the Thank you!
page, click Finish.Congratulations! Windows XP setup is complete. You can log on by clicking yourname on
the logon screen. If you’ve installed Windows XP on a new computer ornew hard disk drive, you can
now use the File and Settings Transfer Wizard to copyyour important data to your computer or hard disk
drive.
Importance of control panel
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Category of computer device management
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Right click my computer icon
Click properties
1.
2.
3.
4.
5.
6.
7.
8.
9.
Main processor - 2. 52 Giga hertz (GHz)
R.a.m (Random Access Memory) 512 Mb (mega bytes)
Pentium® 4 C.p.u (central processing unit)
Hard disk space (40 GB (Giga bytes)
Make e.g Dell, Compaq, Hp, Acer E.t.c
Desktop , laptop or Tower System unit
CRT or TFT Monitor
Keyboard and Mouse (both Ps2 r Usb)
Cd Rom Drive or Dvd W/r
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Networking Configuration Procedures
U-Boot allows user to download/retrieve a image via a TFTP server or NFS server. These
networking supports are not mandatory but will significantly decrease image download time.
This section will describe how to setup a TFTP server and /or a NFS server under CentOS.
NFS server also allows NFS-mount root file system (or NFS mount) on the targeting board. This
is normally used during application development stage. The main idea here is to provide
application/software developers a rapid turnaround during testing and development environment,
because downloading the modified file system image to the target hardware is not necessary.
TFTP Server
Introduction
Trivial File Transfer Protocol (TFTP) is a very simple file transfer protocol, with the
functionality of a very basic form of FTP.
Installing TFTP File Server
Install the TFTPD server (3 packages are needed xinetd, tftp-server, and tftp) on the host
machine if not already exists.
To install xinetd, tftp-server, and tftp in CentOS
$ yum install xinetd tftp-server tftp
Setting up configuration file for TFTP File Server
Create the /tftpboot directory and allow everyone has full control of TFTPBOOT direcotry
$ sudo mkdir /tftpboot
$ sudo chmod -R 777 /tftpboot
$ sudo chown -R nobody /tftpboot
Create /etc/xinetd.d/tftp (if not exists) and include the following
service tftp
{
protocol
port
socket_type
= udp
= 69
= dgram
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wait
user
server
server_args
disable
}
=
=
=
=
=
yes
nobody
/usr/sbin/in.tftpd
/tftpboot
no
Start tftp-server services
$ sudo /etc/init.d/xinetd start
Testing TFTP
Ensure tftpd service is up and running
$ netstat -l -u │ grep tftp
udp
0
0 *:tftp
*:*
Create a foo file under /tftpboot directory and see if you can grab a file
$ tftp localhost
tftp> get foo
tftp> quit
$ ls -l foo
-rw-r--r-1 wu
wu
0 Oct
8 23:43 foo
NFS Server
Introduction
Network File System (NFS) allows system to share files and folders on the network. This enables
the user to access directories and/or files on a remote machine while appearing to be local files or
directory. NFS support is particular interesting to manage multiple hardware design platform.
Setting up an NFS Server
In order to provide NFS service, two packages must be installed that are nfs-utils and portmap
To install nfs-utils and portmap in CentOS
$ yum install nfs-utils portmap
Setting up Configuration file for PetaLinux environment
The main configuration file you will need to edit to set up an NFS server: /etc/exports. This file
contains a list of entries; each entry indicates a volume that is shared and how it is shared. Check
the man pages (man exports) for a complete description of all the setup options for the file,
although the description here will probably satisfy most people's needs or refer to NFS-HOWTO
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In here we want to share the $PETALINUX/hardware directory with read and write access to all
the machines with IP addresses between 192.168.0.0 and 192.168.0.255 (Local Area Network).
Any read or write operations from remote machine are treated as local user id 500 and local
group id 500.
/home/user/petalinux/hardware \
192.168.0.0/255.255.255.0(rw,sync,all_squash,anonuid=500,anongid=500))
Note: The above example uses IP range from 192.168.0.0 and 192.168.0.255
(192.168.0.0/255.255.255.0) and export path "/home/user/petalinux/hardware". Change as per
appropriate. The text should be entered on a single line, without the continuation backslash ('\')
characters.
To start the NFS and portmap services
$ /etc/rc.d/init.d/portmap.init start
$ /etc/rc.d/init.d/nfs start
This guide will help you to create a windows xp bootable cd . Some times we do copy of
windows cd on hard disk. If we write these copied files on cd it will not boot. Because it will not
be a windows xp bootable cd. To make it windows bootable cd you must have to add boot
image file on cd. To make windows xp bootable cd follow our step by step guides.
The following items are required:




A copy of the original Windows CD/DVD.
A copy of the Boot Files Download from here.
A minimum of 1GB available hard disk space for CD's.
A minimum of 5GB available hard disk space for DVD's.
Extract image files in a folder
There will be image files
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Create a folder named xpcd on c:\ drive and copy the entire windows XP cd or files in it
Now start your CD burning software I have used NERO for it
Select new options from files menu then choose CD-ROM(BOOT)
Do the setting given bellows
Select CD-ROM (Boot).
Click on Boot tabes




Select Image file from Source of boot image data
Click on Browse and choose boot.ima ( where you have extract image files)
Check Enable expert settings (for advanced users only!).
Set Kind of emulation: to No Emulation.
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

Set Load segment of sectors (hex!): to 0000.
Set Number of loaded sectors: to 4.
Click on the ISO tab.






Set File name length to Max. of 31 chars (ISO Level 2).
Set Format to Mode 1.
Set Character Set to ISO 9660 (standard ISO CD-ROM).
Check the Joliet check box.
Check all Relax ISO Restrictions.
Check Allow more than 64 characters for Joliet names.
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Click on the Label tab.


IN ISO 9660 text field Enter volume lable
IN Joliet text boxes. Enter system identifier label
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Click the Burn tab.



Check Write.
Check Finalize CD (No further writing possible!).
Set Write Method to Disc-at-once. (We have had Track-At-Once work as well.)
Click the New button
Locate the folder C:\xpcd ( OR where you have copied xp cd)
Select everything in the folder and drag it to the ISO compilation panel.
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and Click the burn CD Dialog button
Verify the settings. Correct if needed.
Click the Burn button.
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This will launch CD burning wizard
Click the OK button
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Client/Server
Client/server network operating systems allow the network to centralize functions and
applications in one or more dedicated file servers. The server is the center of the system,
allowing access to resources and instituting security. The network operating system provides the
mechanism to integrate all the components on a network to allow multiple users to
simultaneously share the same resources regardless of physical location. [3][4]

Examples:
o Novell Netware
o Windows Server
Advantages




Centralized servers are more stable.
Security is provided through the server.
New technology and hardware can be easily integrated into the system.
Servers are able to be accessed remotely from different locations and types of systems.
Disadvantages



Cost of buying and running a server are high.
Dependence on a central location for operation.
Requires regular maintenance and updates.
Security Issues Involved in using a
Client/Server Network
In a client/server network security issues may evolve at three different locations: the client, the
network, and the server. All three points need to be monitored for unauthorized activity and need
to be secured against hackers or eavesdroppers.
The Client
The client is the end user of the network and needs to be secured the most. The client end usually
exposes data through the screen of the computer. Client connections to server should be secured
through passwords and upon leaving their workstations clients should make sure that their
connection to the server is securely cut off in order to make sure that no hackers or intruders are
able to reach the server data. Not only securing the workstations connection to the server is
important but also securing the files on the workstation (client) is important as it ensures that no
hackers are able to reach the system. Another possibility is that of introducing a virus or running
unauthorized software on the client workstation thus threatening the entire information bank at
the server (Exforsys Inc., 2007).
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The users themselves could also be a security threat if they purposely leave their IDs logged in or
use easy IDs and passwords to enable hacking. Users may also be sharing their passwords in
order to give the hackers access to confidential data (Wilson, Lin, & Craske, 1999). This can be
overcome by giving passwords to each client and regularly asking clients to change their
passwords. Also passwords should be checked for guessability and for their strength and
uniqueness.
The Network
The network allows transmission of data from the clients to the server. There are several points
on the network where a hacker could eavesdrop or steal important packets of information. These
packets may contain important confidential data such as passwords or company details. It is
important that these networks are secured properly to keep unauthorized professionals away from
all the data stored on the server. This can be done by encrypting important data being sent on the
network. However, encryption may not be the only possible way of protecting networks as
hackers can work their way around encryption. Another method could be conducting security
audits regularly and ensuring identification and authorisation of individuals at all points along
the network. This should discourage potential hackers (Wilson, Lin, & Craske, 1999). Making
the entire environment difficult to impersonate also makes sure that the clients are reaching the
true files and applications on the server and that the server is providing information to authorized
personnel only.
The Server
The server can be secured by placing all the data in a secure, centralized location that is protected
through permitting access to authorized personnel only. Virus protection should also be available
on server computers as vast amounts of data can be infected. Regular upgrades should be
provided to the servers as the software and the applications need to be updated. Even the entire
body of data on a server could be encrypted in order to make sure that reaching the data would
require excessive time and effort (Wilson, Lin, & Craske, 1999).
Symbolization
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A sample network diagram
Readily identifiable icons are used to depict common network appliances e.g. Router, and the
style of lines between them indicate the type of connection. Clouds are used to represent
networks external to the one pictured for the purposes of depicting connections between internal
and external devices, without indicating the specifics of the outside network. For example, in the
hypothetical local area network pictured to the right, three personal computers and a server are
connected to a switch; the server is further connected to a printer and a gateway router, which is
connected via a WAN link to the Internet.[1]
Depending on whether the diagram is intended for formal or informal use, certain details may be
lacking and must be determined from context. For example, the sample diagram does not
indicate the physical type of connection between the PCs and the switch, but since a modern
LAN is depicted, Ethernet may be assumed. If the same style of line was used in a WAN (wide
area network) diagram, however, it may indicate a different physical connection.
At different scales diagrams may represent various levels of network granularity. At the LAN
level, individual nodes may represent individual physical devices, such as hubs or file servers,
while at the WAN level, individual nodes may represent entire cities. In addition, when the scope
of a diagram crosses the common LAN/MAN/WAN boundaries, representative hypothetical
devices may be depicted instead of showing all actually existing nodes. For example, if a
network appliance is intended to be connected through the Internet to many end-user mobile
devices, only a single such device may be depicted for the purposes of showing the general
relationship between the appliance and any such device.
Personal computer
From Wikipedia, the free encyclopedia
Jump to: navigation, search
This article is about personal computers in general. For hardware components of personal computers,
see Personal computer hardware.
Personal computer
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An illustration of a personal desktop computer
A personal computer (PC) is any general-purpose computer whose size, capabilities, and
original sales price make it useful for individuals, and which is intended to be operated directly
by an end-user with no intervening computer operator. This contrasted with the batch processing
or time-sharing models which allowed larger, more expensive minicomputer and mainframe
systems to be used by many people, usually at the same time. Large data processing systems
require a full-time staff to operate efficiently.
Software applications for most personal computers include, but are not limited to, word
processing, spreadsheets, databases, Web browsers and e-mail clients, digital media playback,
games, and myriad personal productivity and special-purpose software applications. Modern
personal computers often have connections to the Internet, allowing access to the World Wide
Web and a wide range of other resources. Personal computers may be connected to a local area
network (LAN), either by a cable or a wireless connection. A personal computer may be a
desktop computer or a laptop, tablet, or a handheld PC.
Early PC owners usually had to write their own programs to do anything useful with the
machines, even lacking an operating system. The very earliest microcomputers, equipped with a
front panel, required hand-loading of a bootstrap program to load programs from external storage
(paper tape, cassettes, or eventually diskettes). Before very long, automatic booting from
permanent read-only memory became universal.
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Router (computing)
A router is a device that forwards data packets between computer networks, creating an overlay
internetwork. A router is connected to two or more data lines from different networks. When a
data packet comes in one of the lines, the router reads the address information in the packet to
determine its ultimate destination. Then, using information in its routing table or routing policy,
it directs the packet to the next network on its journey. Routers perform the "traffic directing"
functions on the Internet. A data packet is typically forwarded from one router to another through
the networks that constitute the internetwork until it gets to its destination node. [1]
The most familiar type of routers are home and small office routers that simply pass data, such as
web pages and email, between the home computers and the owner's cable or DSL modem, which
connects to the Internet through an ISP. More sophisticated routers, such as enterprise routers,
connect large business or ISP networks up to the powerful core routers that forward data at high
speed along the optical fiber lines of the Internet backbone. Though routers are typically
dedicated hardware devices, use of software-based routers has grown increasingly common.
Applications
When multiple routers are used in interconnected networks, the routers exchange information
about destination addresses, using a dynamic routing protocol. Each router builds up a table
listing the preferred routes between any two systems on the interconnected networks. A router
has interfaces for different physical types of network connections, (such as copper cables, fiber
optic, or wireless transmission). It also contains firmware for different networking protocol
standards. Each network interface uses this specialized computer software to enable data packets
to be forwarded from one protocol transmission system to another.
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Routers may also be used to connect two or more logical groups of computer devices known as
subnets, each with a different sub-network address. The subnets addresses recorded in the router
do not necessarily map directly to the physical interface connections. [2] A router has two stages
of operation called planes:[3]

Control plane: A router records a routing table listing what route should be used to forward a
data packet, and through which physical interface connection. It does this using internal preconfigured addresses, called static routes.
A typical home or small office router showing the ADSL telephone line and Ethernet network cable
connections

Forwarding plane: The router forwards data packets between incoming and outgoing interface
connections. It routes it to the correct network type using information that the packet header
contains. It uses data recorded in the routing table control plane.
Routers may provide connectivity within enterprises, between enterprises and the Internet, and
between internet service providers (ISPs) networks. The largest routers (such as the Cisco CRS-1
or Juniper T1600) interconnect the various ISPs, or may be used in large enterprise networks. [4]
Smaller routers usually provide connectivity for typical home and office networks. Other
networking solutions may be provided by a backbone Wireless Distribution System (WDS),
which avoids the costs of introducing networking cables into buildings.
All sizes of routers may be found inside enterprises.[5] The most powerful routers are usually
found in ISPs, academic and research facilities. Large businesses may also need more powerful
routers to cope with ever increasing demands of intranet data traffic. A three-layer model is in
common use, not all of which need be present in smaller networks. [6]
Access
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A screenshot of the LuCI web interface used by OpenWrt. This page configures Dynamic DNS.
Access routers, including 'small office/home office' (SOHO) models, are located at customer
sites such as branch offices that do not need hierarchical routing of their own. Typically, they are
optimized for low cost. Some SOHO routers are capable of running alternative free Linux-based
firmwares like Tomato, OpenWrt or DD-WRT.[7]
Distribution
Distribution routers aggregate traffic from multiple access routers, either at the same site, or to
collect the data streams from multiple sites to a major enterprise location. Distribution routers are
often responsible for enforcing quality of service across a WAN, so they may have considerable
memory installed, multiple WAN interface connections, and substantial onboard data processing
routines. They may also provide connectivity to groups of file servers or other external networks.
Security
External networks must be carefully considered as part of the overall security strategy. Separate
from the router may be a firewall or VPN handling device, or the router may include these and
other security functions. Many companies produced security-oriented routers, including Cisco
Systems' PIX and ASA5500 series, Juniper's Netscreen, Watchguard's Firebox, Barracuda's
variety of mail-oriented devices, and many others.
Core
In enterprises, a core router may provide a "collapsed backbone" interconnecting the distribution
tier routers from multiple buildings of a campus, or large enterprise locations. They tend to be
optimized for high bandwidth, but lack some of the features of Edge Routers. [8]
Internet connectivity and internal use
Routers intended for ISP and major enterprise connectivity usually exchange routing information
using the Border Gateway Protocol (BGP). RFC 4098[9] standard defines the types of BGPprotocol routers according to the routers' functions:
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







Edge router: Also called a Provider Edge router, is placed at the edge of an ISP network. The
router uses External BGP to EBGP protocol routers in other ISPs, or a large enterprise
Autonomous System.
Subscriber edge router: Also called a Customer Edge router, is located at the edge of the
subscriber's network, it also uses EBGP protocol to its provider's Autonomous System. It is
typically used in an (enterprise) organization.
Inter-provider border router: Interconnecting ISPs, is a BGP-protocol router that maintains BGP
sessions with other BGP protocol routers in ISP Autonomous Systems.
Core router: A core router resides within an Autonomous System as a back bone to carry traffic
between edge routers.[10]
Within an ISP: In the ISPs Autonomous System, a router uses internal BGP protocol to
communicate with other ISP edge routers, other intranet core routers, or the ISPs intranet
provider border routers.
"Internet backbone:" The Internet no longer has a clearly identifiable backbone, unlike its
predecessor networks. See default-free zone (DFZ). The major ISPs system routers make up
what could be considered to be the current Internet backbone core. [11] ISPs operate all four
types of the BGP-protocol routers described here. An ISP "core" router is used to interconnect
its edge and border routers. Core routers may also have specialized functions in virtual private
networks based on a combination of BGP and Multi-Protocol Label Switching protocols.[12]
Port forwarding: Routers are also used for port forwarding between private internet connected
servers.[5]
Voice/Data/Fax/Video Processing Routers: Commonly referred to as access servers or gateways,
these devices are used to route and process voice, data, video, and fax traffic on the internet.
Since 2005, most long-distance phone calls have been processed as IP traffic (VOIP) through a
voice gateway. Voice traffic that the traditional cable networks once carried[clarification needed]. Use
of access server type routers expanded with the advent of the internet, first with dial-up access,
and another resurgence with voice phone service.
Ethernet hub
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4-port Ethernet hub
An Ethernet hub, active hub, network hub, repeater hub, multiport repeater or hub is a
device for connecting multiple Ethernet devices together and making them act as a single
network segment. It has multiple input/output (I/O) ports, in which a signal introduced at the
input of any port appears at the output of every port except the original incoming. A hub works
at the physical layer (layer 1) of the OSI model.[1] The device is a form of multiport repeater.
Repeater hubs also participate in collision detection, forwarding a jam signal to all ports if it
detects a collision.
Some hubs may also come with a BNC and/or Attachment Unit Interface (AUI) connector to
allow connection to legacy 10BASE2 or 10BASE5 network segments. The availability of lowpriced network switches has largely rendered hubs obsolete but they are still seen in 20th century
installations and more specialized applications.
Dual-speed hub
In the early days of fast Ethernet, Ethernet switches were relatively expensive devices. Hubs
suffered from the problem that if there were any 10BASE-T devices connected then the whole
network needed to run at 10 Mbit/s. Therefore a compromise between a hub and a switch was
developed, known as a dual-speed hub. These devices consist of an internal two-port switch,
bridging the 10 Mbit/s and 100 Mbit/s segments. The device would typically consist of more
than two physical ports. When a network device becomes active on any of the physical ports, the
device attaches it to either the 10 Mbit/s segment or the 100 Mbit/s segment, as appropriate. This
prevented the need for an all-or-nothing migration to fast Ethernet networks. These devices are
considered hubs because the traffic between devices connected at the same speed is not switched.
Uses
Historically, the main reason for purchasing hubs rather than switches was their price. This
motivator has largely been eliminated by reductions in the price of switches, but hubs can still be
useful in special circumstances:



For inserting a protocol analyzer into a network connection, a hub is an alternative to a network
tap or port mirroring.[5]
When a switch is accessible for end users to make connections, for example, in a conference
room, an inexperienced or careless user (or saboteur) can bring down the network by
connecting two ports together, causing a loop. This can be prevented by using a hub, where a
loop will break other users on the hub, but not the rest of the network. This hazard can also be
avoided by using switches that can detect and deal with loops, for example by implementing the
spanning tree protocol.
A hub with a 10BASE2 port can be used to connect devices that only support 10BASE2 to a
modern network. The same goes for linking in an old 10BASE5 network segment using an AUI
port on a hub. Individual devices that were intended for thicknet can also be linked to modern
Ethernet by using an AUI-10BASE-T transceiver.
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Network switch
Avaya ERS 2550T-PWR 50-port network switch
A network switch is a computer networking device that links network segments or network
devices. The term commonly refers to a multi-port network bridge that processes and routes data
at the data link layer (layer 2) of the OSI model. Switches that additionally process data at the
network layer (layer 3) and above are often called layer-3 switches or multilayer switches.
The first Ethernet switch was introduced by Kalpana in 1990.
Wide area network
Computer network types by
geographical scope

Near field (NFC)

Body (BAN)

Personal (PAN)

Near-me (NAN)

Local (LAN)
o
Home (HAN)
o
Storage (SAN)
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
Campus (CAN)

Backbone

Metropolitan (MAN)

Wide (WAN)

Internet

Interplanetary Internet

v

t

e
A Wide Area Network (WAN) is a network that covers a broad area (i.e., any
telecommunications network that links across metropolitan, regional, or national boundaries)
using private or public network transports. Business and government entities utilize WANs to
relay data among employees, clients, buyers, and suppliers from various geographical locations.
In essence, this mode of telecommunication allows a business to effectively carry out its daily
function regardless of location. The Internet can be considered a WAN as well, and is used by
businesses, governments, organizations, and individuals for almost any purpose imaginable. [1]
Related terms for other types of networks are personal area networks (PANs), local area
networks (LANs), campus area networks (CANs), or metropolitan area networks (MANs) which
are usually limited to a room, building, campus or specific
Network packet
In computer networking, a packet is a formatted unit of data carried by a packet mode computer
network. Computer communications links that do not support packets, such as traditional pointto-point telecommunications links, simply transmit data as a series of bytes, characters, or bits
alone. When data is formatted into packets, the bitrate of the communication medium can be
better shared among users than if the network were circuit switched.
Types of wireless networks
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Wireless PAN
Wireless personal area networks (WPANs) interconnect devices within a relatively small area,
that is generally within a person's reach.[3] For example, both Bluetooth radio and invisible
infrared light provides a WPAN for interconnecting a headset to a laptop. ZigBee also supports
WPAN applications.[4] Wi-Fi PANs are becoming commonplace (2010) as equipment designers
start to integrate Wi-Fi into a variety of consumer electronic devices. Intel "My WiFi" and
Windows 7 "virtual Wi-Fi" capabilities have made Wi-Fi PANs simpler and easier to set up and
configure.[5]
Wireless LAN
Main article: Wireless LAN
A wireless local area network (WLAN) links two or more devices over a short distance using a
wireless distribution method, usually providing a connection through an access point for Internet
access. The use of spread-spectrum or OFDM technologies may allow users to move around
within a local coverage area, and still remain connected to the network.
Products using the IEEE 802.11 WLAN standards are marketed under the Wi-Fi brand name.
Fixed wireless technology implements point-to-point links between computers or networks at
two distant locations, often using dedicated microwave or modulated laser light beams over line
of sight paths. It is often used in cities to connect networks in two or more buildings without
installing a wired link.
Wireless mesh network
Main article: wireless mesh network
A wireless mesh network is a wireless network made up of radio nodes organized in a mesh
topology. Each node forwards messages on behalf of the other nodes. Mesh networks can "self
heal", automatically re-routing around a node that has lost power.
Wireless MAN
Wireless metropolitan area networks are a type of wireless network that connects several
wireless LANs.

WiMAX is a type of Wireless MAN and is described by the IEEE 802.16 standard.[6]
Wireless WAN
Wireless wide area networks are wireless networks that typically cover large areas, such as
between neighboring towns and cities, or city and suburb. These networks can be used to connect
branch offices of business or as a public internet access system. The wireless connections
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between access points are usually point to point microwave links using parabolic dishes on the
2.4 GHz band, rather than omnidirectional antennas used with smaller networks. A typical
system contains base station gateways, access points and wireless bridging relays. Other
configurations are mesh systems where each access point acts as a relay also. When combined
with renewable energy systems such as photo-voltaic solar panels or wind systems they can be
stand alone systems.
Cellular network
Main article: cellular network
Top of a cellular radio tower
A cellular network or mobile network is a radio network distributed over land areas called
cells, each served by at least one fixed-location transceiver, known as a cell site or base station.
In a cellular network, each cell characteristically uses a different set of radio frequencies from all
their immediate neighbouring cells to avoid any interference.
When joined together these cells provide radio coverage over a wide geographic area. This
enables a large number of portable transceivers (e.g., mobile phones, pagers, etc.) to
communicate with each other and with fixed transceivers and telephones anywhere in the
network, via base stations, even if some of the transceivers are moving through more than one
cell during transmission.
Although originally intended for cell phones, with the development of smartphones, cellular
telephone networks routinely carry data in addition to telephone conversations:

Global System for Mobile Communications (GSM): The GSM network is divided into three major
systems: the switching system, the base station system, and the operation and support system.
The cell phone connects to the base system station which then connects to the operation and
support station; it then connects to the switching station where the call is transferred to where
it needs to go. GSM is the most common standard and is used for a majority of cell phones. [7]
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

Personal Communications Service (PCS): PCS is a radio band that can be used by mobile phones
in North America and South Asia. Sprint happened to be the first service to set up a PCS.
D-AMPS: Digital Advanced Mobile Phone Service, an upgraded version of AMPS, is being phased
out due to advancement in technology. The newer GSM networks are replacing the older
system.
A wireless site survey, sometimes called an RF site survey or wireless survey, is the process of
planning and designing a wireless network, to provide a wireless solution that will deliver the
required wireless coverage, data rates, network capacity, roaming capability and Quality of
Service (QoS).[1] The survey usually involves a site visit to test for RF interference, and to
identify optimum installation locations for access points. This requires analysis of building floor
plans, inspection of the facility, and use of site survey tools. Interviews with IT management and
the end users of the wireless network are also important to determine the design parameters for
the wireless network.
Question
How do I extract or uncompress a compressed file?
Answer
Before extracting the data from the compressed file you must first determine the compressed file
type. On a IBM compatible computer running Windows this can be determined by the file
extension. Most compressed files are either .ZIP, .RAR, TAR.GZ, or .TGZ files. Below are
some examples of what some of the different compressed icons look like in Microsoft Windows.
Once the compressed file type has been determined, use the appropriate program. For example,
many users use WinZip and Pkzip to extract .ZIP files and WinRAR to extract RAR files in
Windows. However, we recommend Windows users use 7-Zip since this program is free, open
source, and supports all major compressed file formats.
Download 7-Zip
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Tip: If you are using Microsoft Windows XP, Vista, 7, or later your computer should already be
cable of extracting the contents of ZIP files.
Tip: If you don't want to or can't install a program on your computer you can also compress and
uncompress files online.
Once a compression program has been installed on the computer, you can extract the contents
from the compressed file. Below are some basic steps on how you can extract files.
How is data read and stored on a hard drive?
Data sent to and from the hard drive is interpreted by the disk controller, which tells the hard
drive what to do and how to move the components within the drive. When the operating system
needs to read or write information, it examines the hard drives File Allocation Table (FAT) to
determine file location and available areas. Once this has been determined, the disk controller
instructs the actuator to move the read/write arm and align the read/write head. Because files are
often scattered throughout the platter, the head will often need to move to several different
locations to access all information.
All information stored on a traditional hard drive, like the above example, is done magnetically.
After completing the above steps, if the computer needs to read information from the hard drive
it would read the magnetic polarities on the platter. One side of the magnetic polarity is 0 and the
other is 1, reading this as binary data the computer can understand what the data is on the platter.
For the computer to write information to the platter, the read/write head aligns the magnetic
polarities, writing 0's and 1's that can be read later.
Can a computer run without hardware?
Depends on the hardware. Almost all computer setups will require at least a
disk drive (e.g. hard drive), display, keyboard, memory, motherboard, processor, power supply,
and video card in order to function properly. If any of these devices was missing or had
problems, an error would be encountered, or the computer would not start. Adding other
hardware such as a disc drive (e.g. CD-ROM or DVD), modem, mouse, network card, printer,
sound card, speakers, etc. are not required, but will give the computer additional capabilities.
How to replace the CMOS battery
Issue
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How to replace the CMOS battery.
Cause
Like any battery the computer CMOS battery can fail or lose its charge.
Solution
If your computer is losing its time or date settings, or you are receiving a message CMOS Read
Error, CMOS checksum error, or CMOS Battery Failure, first try leaving the computer on
for 24-hours. In some cases this can charge the battery and resolve your issue. This often
resolves CMOS battery related issues when a computer has been left off for several months. If
this does not resolve your issue follow the below steps.
Locate your CMOS battery
Caution: When inside your computer make sure you're aware of ESD and all it's potential
dangers.
Open the computer case and find the battery on the computer
motherboard, verify that it will be accessible and that it can be removed. Most computers today
use a coin cell CMOS battery as shown in the image to the right.
Tip: Some CMOS batteries may be held down by a metal clip or bar. This clip just holds the
battery in place and the battery can still be removed by sliding it under the clip. Do not bend this
clip to get the battery out.
If you are unable to locate your CMOS battery refer to your motherboard or computer
documentation or contact your computer manufacturer for additional assistance in locating it.
Obtain battery information
Unfortunately, most manufacturers will not list the exact type and model of your CMOS battery;
therefore, once you have located the battery, write down all information about the battery
(Voltage, chemistry, wiring, and packaging). If possible, remove the battery and take it to the
location you plan on purchasing a new battery from. The part number for this battery for most
computers is CR2032.
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Additional buying information can be found on our battery buying tips page.
Removing the battery
Caution: When inside your computer make sure you're aware of ESD and all it's potential
dangers.
If you're computer is using a coin cell battery similar to the above example picture. Removing
the battery is relatively simple. use your fingers to grab on the edge of the battery and pull it up
and out of the container holding it. Some motherboards have a clip holding the battery down. If
your computer has this clip you may need to use one had to move the clip up and the other hand
to pull the battery out.
Unfortunately, not all CMOS batteries are removable; some manufactures will only allow a
replacement battery to be added. If you're not using a coin cell battery and are not able to
determine how to remove it refer to your motherboard or computer documentation or contact
your computer manufacturer for additional assistance in removing the battery or how to insert a
new replacement battery.
Users with computers that do not have removable batteries only options to install a new battery
will most likely also need to set a jumper when adding the new battery into their computer.
Insert the new battery
Once you have purchased a new battery, remove the old battery (as instructed above) and replace
it with the new battery.
Enter CMOS values
Once the battery is replaced turn on the computer and resetting the CMOS values to the defaults.
After the values have all been entered make sure to save the settings before exiting. Many
CMOS setups allow you to press a key (such as F10) to save values and exit all in one action.
If after following all the above steps you continue to experience the same error when your
computer starts or your computer is still unable to keep the stored values it's likely that you're
experiencing a more serious issues. Most likely causes are bad power supply or bad
motherboard.
Each time the computer boots I receive a
prompt for the time and date
Issue
Each time the computer boots I receive a prompt for the time and date.
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Cause
1. Missing autoexec.bat or config.sys.
2. Bad or missing CMOS or RTC battery.
Solution
If your computer has been able to keep the time and date in the past and has suddenly started
prompting you for the time and date, and you are running Microsoft Windows 95, Windows 3.x,
or MS-DOS, verify that the computer has an autoexec.bat and config.sys file. If this file is
missing it will need to be recreated or restored from a backup.
It is common for computers using an Intel 80286 and lower processor to not have a CMOS or
RTC battery. If your computer does not have a CMOS or RTC battery, it is functioning as
designed.
If you have a computer later than a 80286 or a computer that has been built in the last few years,
it is likely that your CMOS or RTC battery has died. Contact your computer or motherboard
manufacturer to purchase a replacement battery or if you have a coin cell battery on your
motherboard you may also want to find a replacement online or through a local electronics store
such as Radio Shack.
Below is a listing of general tips that should be taken when cleaning any of the components or
peripherals of a computer as well as tips to help keep a computer clean.
1. Never spray or squirt any liquid onto any computer component. If a spray is needed,
spray the liquid onto a cloth and then use that cloth to rub down the component.
2. You can use a vacuum to suck up dirt, dust, or hair around the computer on the outside
case. However, do not use a vacuum for the inside of your computer as it generates a lot
of static electricity that can damage the internal components of your computer. If you
need to use a vacuum to clean the inside of your computer, use a portable battery
powered vacuum designed to do this job or try using compressed air.
3. When cleaning a component or the computer, turn it off before cleaning.
4. Be cautious when using any cleaning solvents; some individuals may have allergic
reactions to chemicals in cleaning solvents and some solvents can even damage the case.
Try to always use water or a highly diluted solvent.
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5. When cleaning, be careful not to accidentally adjust any knobs or controls. In addition,
when cleaning the back of the computer, if anything is plugged in, make sure not to
disconnect any of the plugs.
6. When cleaning fans, especially the smaller fans within a portable computer or laptop it's
suggested that you either hold the fan or place something in-between the fan blades to
prevent it from spinning. Spraying compressed air into a fan or cleaning a fan with a
vacuum may cause damage or back voltage to be generated.
7. Never eat or drink around the computer.
8. Limit smoking around the computer.
Cleaning tools
Although many companies have created products to help improve the process of cleaning your
computer and peripherals, users can also use household items to clean their computers and
peripherals. Below is a listing of items you may need or want to use while cleaning your
computer or computer peripherals.
Keep in mind that some components in your computer may only be able to be cleaned using a
product designed for cleaning that component; if this is the case, it will be mentioned in the
cleaning tips.





Cloth - A cloth is the best tool used when rubbing down a component; although paper
towels can be used with most hardware, we recommend using a cloth when ever possible.
Caution: We only suggest you use a cloth when cleaning components such as the outside
of the case, a drive, mouse, etc. You should not use a cloth to clean any circuitry such as
the RAM or motherboard since they can generate ESD that can damage electronics.
Water or rubbing alcohol - When moistening a cloth, it is best to use water or rubbing
alcohol. Other solvents may be bad for the plastics used with your computer.
Portable Vacuum - Sucking the dust, dirt, hair, cigarette particles, and other particles out
of a computer can be one of the best methods of cleaning a computer. Over time, these
items can restrict the airflow in a computer and cause circuitry to corrode. Do not use a
standard vacuum as it can generate a lot of static electricity that can damage your
computer.
Cotton swabs - Cotton swaps moistened with rubbing alcohol or water are excellent
tools for wiping hard to reach areas in your keyboard, mouse, and other locations.
Foam swabs - Whenever possible, it is better to use lint-free swabs such as foam swabs.
Case cleaning
Why? Keeps the appearance of the computer looking new. During cleaning, if ventilation
locations are found, these can be cleaned helping the case keep a steady airflow to the computer,
keeping components cool and in good working condition.
Procedure: The plastic case that houses the PC components can be cleaned with a lint-free cloth
that has been slightly dampened with water. For stubborn stains, add a little household detergent
to the cloth. It is recommended that you never use a solvent cleaner on plastics.
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Make sure all vents and air holes are hair and lint free by rubbing a cloth over the holes and
vents. It is also helpful to take a vacuum around each of the hole, vents, and crevices on the
computer. It is safe to use a standard vacuum when cleaning the outside vents of a computer;
however, if you need to clean the inside of the computer, use a portable battery powered vacuum
to prevent static electricity.
If you are looking for steps on cleaning the inside of the computer, see the motherboard cleaning
section.
CD-ROM, DVD, and other disc drive cleaning
Why? A dirty CD-ROM drive or other disc drives can cause read errors when reading discs.
These read errors could cause software installation issues or issues while running the program.
Procedure: To clean the CD-ROM drive we recommend purchasing a CD-ROM cleaner from
your local retailer such as a local Radio Shack. Using a CD-ROM cleaner should sufficiently
clean the CD-ROM laser from dust, dirt, and hair.
In addition to cleaning the drive with a special disc designed to clean drives users can also use a
cloth dampened with water to clean the tray that ejects from the drive. Make sure however that
after the tray has been cleaned that it completely dry before putting the tray back into the drive.
See the CD cleaning recommendation for further steps on cleaning each of your CDs.
Additional help: CD-ROM Page
CD and DVD disc cleaning
Why? Dirty CDs can cause read errors or cause CDs to not work at all.
Procedure: Cleaning CDs and DVDs should be done with a cleaning kit but can also be done
with a normal clean cotton cloth or shirt. When doing this with a clean cotton cloth or shirt, wipe
against the tracks, starting from the middle of the CD or DVD and wiping towards the outer side
as shown in the below picture. Never wipe with the tracks; doing so may put more scratches on
the disc.
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It is recommended when cleaning a CD that water is used. However, if the substance on a CD
cannot be removed using water, pure alcohol can also be used.
Hard drive cleaning
Why? While hard drives cannot be cleaned physically, they can be cleaned with various utilities
on the computer to help it run fast and more efficiently. Utilizing these utilities will prevent the
hard drive from slowing down.
Procedure: Refer to our basic troubleshooting section for your operating system for steps that
can be done to help improve the performance of your computer.
Additional help: Hard drive page
Headphones cleaning
Why? Headphones that are used by multiple people may need to be cleaned frequently to help
prevent the spreading of germs and head lice.
Procedure: If the headphones being used are plastic or vinyl, moisten a cloth with warm water
and rub the head and earpieces of the headphones. As mentioned earlier in our cleaning tips, it is
recommended that if your headphones are being used for a library or school that you do not use
any disinfectant or cleaning solvent as users may have allergic reactions to the chemicals they
contain.
Headphones that have cushions also have the availability of having the cushions replaced.
Replacing these cushions can also help keep the headphones clean.
Finally, in regards to headphones and the spreading of head lice, if multiple students are using
your headphones, you should consider having the students use their own headphones, using bags
that are placed over the headphones, or having headphones that can be wiped with warm water
after each student has used the headphones.
Keyboard cleaning
The below steps are for cleaning a standard desktop keyboard. See the cleaning a laptop
keyboard page for steps if you have a laptop.
Dust, dirt, and bacteria
The computer keyboard is often the most germ infected items in your home or office, often it
will contain more bacteria than your toilet seat. Cleaning it can help remove any dangerous
bacteria. Dirt, dust and hair can also build up causing the keyboard to not function properly.
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Procedure: Before cleaning the keyboard first turn off the computer or if you're using a USB
keyboard unplug it. Not unplugging the keyboard can result in causing other computer problems
as you may press keys that cause the computer to perform a task you don't want it to do.
Many people clean the keyboard by turning it upside down and shaking. A more effective
method is to use compressed air. Compressed air is pressurized air contained in a can with a very
long nozzle. aim the air between the keys and blow away all of the dust and debris that has
gathered there. A vacuum cleaner can also be used, but make sure the keyboard doesn't have
loose "pop off" keys that could possibly be sucked up by the vacuum.
If you wish to clean the keyboard more extensively you'll need to remove the keys from the
keyboard.
After the dust, dirt, and hair has been removed. Spray a disinfectant onto a cloth or use
disinfectant cloths and rub each of the keys on the keyboard. As mentioned in our general
cleaning tips, never spray any liquid onto the keyboard.
Substance spilt into the keyboard
If the keyboard has anything spilt into it (e.g. pop, cola, Pepsi, Coke, beer, wine, coffee, milk,
etc.), not taking the proper steps can cause the keyboard to be destroyed.
Procedure: Below are a few recommendations to help prevent a keyboard from becoming bad
once a substance has been spilt within it.
If anything is spilt onto the keyboard turn the computer off immediately or at the very least
disconnect it from the computer. Once done flip the keyboard over helping to prevent the
substance from penetrating circuits. While the keyboard is upside down, shake the keyboard over
a surface that can be cleaned later. While still upside down, use a cloth to help clean out what
can be reached. After cleaned to the best of your ability leave the keyboard upside down for at
least one night allowing it to dry. Once dry, continue cleaning the keyboard with any remaining
substance.
If after cleaning the keyboard you have keys that stick remove the keys and clean below the keys
and the bottom portion of the key.
Finally, if the keyboard still works but remains dirty or sticky before discarding the keyboard as
a last resort try washing the keyboard in the dishwasher.
If after doing all the above steps the keyboard does not function properly or at all it's
recommended you buy a new keyboard.
Additional Information: Keyboard Page
LCD cleaning
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Why? Dirt, dust, and finger prints can cause the computer screen to be difficult to read.
Procedure: Unlike a computer monitor, the LCD or flat-panel display is not made of glass,
therefore requires special cleaning procedures.
When cleaning the LCD screen it is important to remember to not spray any liquids onto the
LCD directly, press gently while cleaning, and do not use a paper towel as it may cause the LCD
to become scratched.
To clean the LCD screen we recommend that you use a non-rugged microfiber cloth, soft cotton
cloth, or Swiffer duster. If a dry cloth does not completely clean the screen, you can apply
rubbing alcohol to the cloth and wipe the screen with the damp cloth. Rubbing alcohol is used to
clean the LCD before it leaves the factory.
Monitor cleaning
Tip: This section is for computer monitors if you have a LCD or flat-panel see the LCD cleaning
section.
Why? Dirt, dust, and fingerprints can cause the computer screen to be difficult to read.
Procedure: The glass monitor screen can be cleaned with ordinary household glass cleaner*. Be
sure to remove power from the monitor and spray the cleaner onto a lint free-cloth so the fluid
doesn't leak into the electrical components inside the monitor. Vacuum off any dust that has
settled on top of the monitor, and make sure no books or papers have been placed on the air
vents. Obstructed monitor vents can cause the monitor to overheat or even catch on fire.
Caution: We suggest using a cloth dampened with water when cleaning monitor on a screen that
is not made of glass or has any anti-glare protection on the screen. Using ordinary household
glass cleaner on special screens, especially cleaners with ammonia can remove anti-glare
protection or other special surfaces.
Other good cleaning solutions


Microfiber Towels
Swiffer Dusters
Motherboard cleaning
Why? Dust and especially particles of cigarette smoke can build up and corrode circuitry
causing various problems such as computer lockups
Caution: When inside the computer take the necessary ESD precautions and try to avoid
unplugging any cables or other connections.
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Procedure: Our recommendation when cleaning the motherboard from dust, dirt, or hair is to
use compressed air. When using compressed air, hold it in the up-right position; otherwise, it is
possible chemicals may come out of the container that could damage or corrode the Motherboard
or other component within the computer. Also, ensure when using compressed air that you
always blow the dust or dirt away from the motherboard, or out of the case.
Another good alternative to compressed air is to use a portable battery powered vacuum that can
effectively remove the dust, dirt, and hair from the motherboard completely and prevent it from
getting trapped within the case. However, do not use a standard electricity powered vacuum as it
can cause a lot of static electricity that can damage the computer. When using the vacuum it is
vital that you stay a couple inches away from the motherboard and all other components to help
prevent contact as well as to help prevent anything from being sucked into the vacuum. Ensure
that you do not remove any small components with the vacuum such as jumpers.
Tip: When cleaning the inside of the case also look at any fans or heat sinks. Dust, dirt, and hair
collects around these components the most.
Mouse cleaning
Why? A dirty optical-mechanical mouse (mouse with a ball) can cause the mouse to be difficult
to move as well as cause strange mouse movement.
Procedure: To clean the rollers of an optical-mechanical mouse, you must first remove the
bottom cover of the mouse. To do this, examine the bottom of the mouse to see what direction
the mouse cover should be rotated. As you can see in the below illustration, the mouse cover
must be moved counter clockwise. Place two fingers on the mouse cover and push the direction
of the arrows.
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Once the cover has rotated about an inch, rotate the mouse into
its normal position, covering the bottom of the mouse with one hand and the bottom should fall
off including the mouse ball. If this does not occur, attempt to shake the mouse gently.
Once the bottom cover and the ball are removed, you should be able to see three rollers located
within the mouse. Use a cotton swab, finger, or fingernail to remove any substance. Usually,
there will be a small line of hair and dirt in the middle of the roller, remove as much as this
substance as possible.
Once you have removed as much dirt and hair as possible, place the ball back within the mouse
and place the cover back on.
If the mouse still appears to be having the same issue, repeat the above process; if after several
attempts the mouse is still having the same issues, it's likely that your mouse has other hardware
issues and we recommend that it be replaced.
Note: Cleaning your mouse pad with a damp cloth can also help improve a computer's mouse
movement.
Why? To help keep a mouse clean and germ free it can be helpful to clean the mouse.
Procedure: Use a cloth moistened with rubbing alcohol or warm water and rub the surface of the
mouse and each of its buttons.
Printer cleaning
Why? Cleaning the outside of a printer can help keep the printer's appearance looking good; and
in the case of a printer that is used by many different people, keep the printer clean of germs.
Procedure: First, make sure to turn off the printer before cleaning it. Dampen a cloth with water
or rubbing alcohol and wipe the case and each of the buttons or knobs on the printer. As
mentioned earlier, never spray any liquid directly onto the printer.
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Why? With some printers it may be necessary to clean the inside of the printer to help keep the
printer running smoothly.
Procedure: Because of how many different printers there are, steps in cleaning printers, and
printer manufacturer policies on cleaning the inside of the printer, we recommend you obtain the
printer cleaning steps from your printer manufacturer.
Scanner cleaning
Why? Flatbed scanners commonly become dirty with dust, fingerprints, and hair. When a
scanner is dirty, the images may have distortions.
Procedure: Clean a flatbed scanner's surface by spraying a window cleaner onto a paper towel
or cotton cloth and wipe the glass until clean. As mentioned earlier, never spray a liquid directly
onto the component.
To clean the outside of the scanner, the same towel or cotton cloth can be used.
Miscellaneous cleaning steps
Below are a listing of miscellaneous computer hardware that is rarely used today, but kept on
this page for the few people who are working on older computers and need to clean these
devices.
Floppy drive cleaning
Why? Dirty read/write heads on the floppy drive can cause errors during the reading or writing
process.
Procedures: The floppy drive can be cleaned two different ways. The first method of cleaning a
floppy drive, and our recommended method, is to purchase a kit at your local retail store
designed to clean the read/write heads on your floppy drive.
The second method of cleaning the floppy drive is only recommended for experienced computer
users. Open the floppy drive casing and physically swab the read/write heads with a lint-free
foam swab soaked in pure alcohol, free-on, or trichloroethane. When performing these steps, be
extremely careful when cleaning the heads to ensure that you do not lock them out of alignment
causing the floppy drive to not work. To help prevent the heads from becoming out of alignment,
use a dabbing motion lightly putting the swab on the head and removing it, do not perform a
side-to-side motion with the swab.
Palm pilot cleaning
Why? Dirty touch screens can cause difficult navigation.
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Procedure: To clean the Palm Pilot Screen, use a soft cloth moistened with rubbing alcohol and
rub the screen and the casing of the palm pilot. It is not recommended to use glass cleaner as it
could damage plastics over time.
SuperDisk and LS120 cleaning
Why? It is recommended that the SuperDisk and LS120 drive be cleaned regularly to prevent
drive heads from becoming dirty.
Procedure: Purchase the SuperDisk cleaning kit available through Imation. Using any other
method will void the warranty on your drive.
Additional help: Super disk page
How do I determine if I have a 64-bit or 32bit CPU?
Question
How do I determine if I have 64-bit vs. 32-bit CPU?
Answer
Determine Windows version
If you're wanting to determine the version of Windows your computer is running follow the
below steps for your version of Windows. Keep in mind that a 64-bit processor can be using
either 32-bit or 64-bit version of Windows and that a 32-bit processor can only use a 32-bit
version of Windows.
Windows Vista and Windows 7 users
Windows XP users
Windows Vista and Windows 7 users
1. Press and Hold the Windows Key and the Pause key or open the System and Security, System
section in Control panel.
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2. In the System window by System type you'll have 32-bit Operating System if you're running a
32-bit version of Vista, and 64-bit Operating System if you're running the 64-bit version. Below
is an example of what this would look like.
Windows XP users
1. Press and Hold the Windows Key and the Pause key or open the System icon in Control panel.
2. In the General tab of the System Properties window if your computer says Windows XP you're
running the 32-bit version of Windows. If the computer is saying Windows XP Professional x64
Edition you're running the 64-bit version of Windows XP.
32-bit
1. Computers, operating systems, or software programs capable of transferring data 32-bits
at a time. A good example of the first 32-bit operating system is OS/2 and Windows NT,
often versions of Windows that are 32-bit are referred to as WOW32. Today, 32-bit
computers and operating systems are being replaced by 64-bit computers and operating
systems such as 64-bit versions of Windows 7.
2. The first true 32-bit processor was the Intel 80386.
3. 32-bit can also refer to the amount of colors a video card is displaying. 32-bit is the same
as 16.7 million colors (24-bit color with an 8-bit alpha channel).
64-bit
Replacement for the older x86 or 32-bit platform, 64-bit is a computer or software program that
is capable of transferring 64-bits at a time. When referring to 64-bit, this is referring to a
computer's microprocessor or the computer bus and is also often referred to as WOW64 and x64
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What temperature should my processor be
running at?
Question
What temperature should my processor be running at?
Answer
Depending on the processor, the manufacturer, how fast it runs, where the sensor is located, and
what programs it is currently running will determine the temperature of what the processor
should be. However, this document should give you a general idea of what the processor should
be running at as well as what is acceptable and what is not.
The majority of today's desktop processors should not exceed temperatures of 95C and most will
run between 70-90C. Below are some charts of many of the processors and their average
temperatures. Keep in mind this is only to give our users a general idea of what their processor
should be running at. If you believe your computer is running to hot, you may wish to skip to the
bottom of this document for additional details on how to get exact information about what your
processor should be running at.
Processors
Average temperature
AMD Athlon
90C - 95C
AMD Athlon64
65C - 70C
AMD Athlon64 Mobile 95C - 100C
AMD Athlon MP
90C - 95C
AMD Athlon XP
85C - 90C
AMD Duron
85C - 95C
AMD Opteron
65C - 71C
AMD Sempron
90C - 95C
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AMD K5
60C - 70C
AMD K6
65C - 70C
AMD K6 Mobile
80C - 85C
AMD K7 Thunderbird 70C - 95C
Intel Pentium II
65C - 75C
Intel Pentium III
60C - 85C
Intel Celeron
67C - 85C
Intel Pentium Mobile 100C
Intel Pentium Pro
80C - 85C
How will I know if my processor is running too hot?
If a processor gets too hot you will notice one or more of the below situations. Often these issues
will be encountered when running programs or especially when playing an advanced game.
1. Computer runs much slower
2. Computer restarts often
3. Computer randomly turns off
Continuing to use a computer that has a processor that is exceeding its temperature will reduce
the life expectancy of the processor.
Note: It's possible that with some computer configurations that the thermal sensors may not be
positioned in an optimal location, causing the temperature to be reported cooler or hotter than it
actually is. If your temperature is close to exceeding the maximum temperature or you are
experiencing the above issues, you may want to continue reading the below recommendations for
getting your computer cooler.
What can I do to get my processor cooler?
The cooler the processor runs the more performance you are going to get out of it. Therefore, if
you're looking to overclock your processor or if it's getting too hot, you may need to consider
any or all of the below recommendations.
1. Keep the computer clean - Over time dust, dirt and hair can build up and prevent air from
getting in or out of the case. Make sure your computer case and ventilation is cleaned.
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2. Improve computer's environment - Make sure the computer is running in a good location. The
computer should not be in an enclosed space such as a drawer or cabinet unless there is plenty
of ventilation such as the back of the drawer or cabinet is removed. The computer should not be
in a tight space, there should be at least a two-inch space on both sides of the computer as well
as in the front and back of the computer.
3. Verify fans - Make sure all fans in the computer are properly working. Some motherboards and
computers have fan monitors that will display the RPM of each of the major fans in the
computer and if they are operating properly. Otherwise, you will need to check each of the fans
and look for any spinning issues or listen for any abnormal noises to determine if the fans are
properly working.
4. Thermal paste - If the processor or fan has been replaced or worked on it may be necessary to
clean off and then re-apply the thermal paste that helps transfer the heat away from the
processor.
5. More fans - Consider installing additional fans into the computer. Almost all computers will
come included with a heatsink and fan, as well as a case fan. However, most cases will have the
availability to install a second case fan that can help bring in additional air and help keep the
computer cool. Computer enthusiasts and many overclockers may also create their own air
ducts with fans to help bring in additional air or take out more of the hot air.
6. Better fans - Many computers and processors will come with cheap fans to help bring down the
overall cost of the computer. Installing improved fans or heatsinks that can move the heat away
from the processor better and faster can keep the processor cool.
7. Alternative solutions - More advanced users or users who are overclocking may also wish to
consider alternative solutions such as water cooled solutions to keep their processors cool.
My computer is running slow what steps can
I do to fix it?
Issue
My computer is running slow what steps can I do to fix it?
Cause
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This issue can be caused by any of the below possibilities.
1.
2.
3.
4.
5.
6.
7.
Not enough hard drive space.
Left over programs and bad files.
Data Corruption.
Missing Windows updates or outdated drivers.
Computer is overheating.
Corrupt OS.
Bad Hardware.
Solution
Tip: This page only cover an overall slow computer and not a computer that has a slow boot up.
Below are steps for Microsoft Windows users that should help speed up the computer or
determine why the computer is running slow.
Reboot
If your computer has not been reboot recently make sure to reboot it before following any of the
below steps.
Not enough hard drive space
Verify that there is at least 200-500MB of free hard drive space. This available space allows the
computer to have room for the swap file to increase in size as well as room for temporary files.


Determining available hard drive space.
Regaining computer hard drive space.
Hard drive corrupted or fragmented


Run ScanDisk or something equivalent to verify there is nothing physically wrong with the
computer hard drive.
Run Defrag to help ensure that data is arranged in the best possible order.
Background programs
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Remove or disable any TSRs and startup programs that automatically start each time the
computer boots.
Tip: To see what programs are running in the background and how much memory and CPU they
are using open Task Manager. If you are running Windows 7 run Resmon to get a better
understanding of how your computer is being used.
If you've got an antivirus scanner on the computer, spyware protection program, or other security
utility make sure it's not scanning your computer in the background. Often when these programs
begin to scan the computer it can decrease the overall performance of your computer.
Scan for malware
Today, spyware and other malware is a big cause of many computer problems including a slow
computer. Even if an antivirus scanner is installed on the computer we recommend running a
malware scan on the computer. Use the free version of Malwarebytes to scan your computer for
malware.
Hardware conflicts

Verify that the Device Manager has no conflicts. If any exist resolve these issues as they could be
the cause of your problem.
Update Windows


Make sure you have all the latest Windows updates installed in the computer.
If you are on the Internet when your computer is slow also make sure all browser plugins are upto-date.
Update your drivers
Make sure you've got the latest drivers for your computer, especially the latest video drivers.
Having out-of-date drivers can cause an assortment of issues.
Computer or processor is overheating
Make sure your computer and processor is not overheating. Excessive heat can cause a
significant decrease in computer performance since most processors automatically step the speed
of the processor down to help compensate compensate for the heat related issues.

What temperature should my processor be running at?
Dust, dirt, and hair can also constrict a proper air flow on your computer, which can also cause a
computer to overheat. Make sure your computer case is clean and fans are not obstructed.

Steps on cleaning your computer.
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Memory upgrade
If you've had your computer for more than one year it's likely you're computer is not meeting the
memory requirements for today. Today, we suggest at a minimum the computer have 1GB of
memory.

Determining how much RAM is installed and available.
Specific operating system basic troubleshooting
Basic Microsoft Windows XP troubleshooting.
Basic Microsoft Windows 2000 troubleshooting.
Basic Microsoft Windows NT 4.0 troubleshooting.
Basic Microsoft Windows ME troubleshooting.
Basic Microsoft Windows 98 troubleshooting.
Basic Microsoft Windows 95 troubleshooting.
Basic Microsoft Windows 3.x troubleshooting.
Or go through the other basic troubleshooting steps.
Run registry cleaner
We normally do not recommend registry cleaners. However, if you have followed all of the
above steps and your computer is still slow try running a registry cleaner on the computer.
Erase computer and start over
If none of the above solutions resolve your issues, it is recommended that you either reinstall
Windows or erase everything and then start over.
Old computer
If your computer is older than five years come to terms that it is likely the age of the computer
that is causing it to be slow. Computers progress at an alarming rate as new programs and
updates for programs come out their minimum requirements increase and will cause older
computers to slow down. If your computer is older than five years we suggest purchasing a new
computer or just realize it is going to run slow because it is old.

How often should I buy a new computer?
Hardware issues
Finally, if your computer continues to be slow after going over each of the above
recommendations it's possible that your computer is experiencing a more serious hardware
related issue such as a failing component in the computer. This could be a failing or bad hard
drive, CPU, RAM, motherboard, or other component.
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Windows restarts without warning
Question
Windows restarts without warning.
Cause
This issue could be caused by any of the below possibilities.
1.
2.
3.
4.
5.
Software issue or error.
Hardware issue or error.
Heat related issue.
Computer virus.
Issue with operating system.
Answer
Tip: This document is for computers that are restarting or rebooting by themselves and not
computer's that turn off and remain off.
Software issue or error
Errors generated by software programs can cause a computer to reboot unexpectedly or without
warning. If you are running Windows XP see the below section "For Windows XP users" before
continuing.
If you are not running Windows XP or following the below steps still cause your computer to
reboot without warning. Boot your computer into Safe Mode, and let the computer run in Safe
Mode.
If the computer is still rebooting in Safe Mode the issue is likely not software related but
something else, skip to the next section. If the computer is not rebooting in Safe Mode it is likely
you have software related issue. We would recommend you run through the basic
troubleshooting section for your operating system.
For Windows XP users
Windows XP is designed to automatically reboot each time an error occurs such as a BSoD.
Although this may be nice for errors that do not occur often, users who have a re-occurring error
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may wish to identify the error to troubleshoot it. Below are the steps on how this feature can be
disabled and enabled in Windows XP.
1.
2.
3.
4.
5.
6.
From the desktop right-click on My Computer.
Click the Properties option.
In the System Properties window click the Advanced tab.
In Advanced click the Settings button under Startup and Recovery.
In the Startup and Recovery window uncheck the Automatically restart check box.
Click Ok.
Now if the computer generates and error it should not automatically restart and enable you to
display any errors your computer may be experiencing.
Hardware issue or error
Caution: Some of the below steps require you open your computer. While in the computer, be
cautious of ESD.
Any failing hardware component in your computer could cause your computer to unexpectedly
generate an error or reboot without warning. If you have recently attempted to add a new
hardware device, remove that device to make sure it is not causing your issues.
Make sure you are not encountering any hardware conflicts by viewing Device Manager for
errors.
New drivers can also cause this issue, if you have recently performed any hardware driver
updates you may wish to try an earlier version of the drivers. Additional information and help
with computer drivers can be found on our drivers page.
If you have updated drivers and removed any hardware that could be causing this issue and
continue to experience random reboots, it's possible that the memory is bad in the computer.

How can I test my memory to determine if it is bad?
Finally, hardware devices that are not installed properly in the computer can also cause random
reboots. Make sure all the cables and expansion cards are connected properly to the computer.
The best way to determine this is to disconnect and reconnect all cables and expansion cards.
Computer virus
Computer viruses such as the blaster virus are written to reboot your computer without warning.
Usually these viruses will make the computer reboot ever 5, 10, 15 or 30 minutes after the
computer has booted.
If you believe your computer may be infected with a virus or are uncertain if your computer is
infected with a virus make sure your virus scanner definitions are up to date.
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
How do I update my antivirus program?
Heat related issue
Many computer today are designed to turn off or automatically reboot if the computer, processor,
or other device in your computer gets to hot. If you have heard any abnormal noises coming from
your computer recently such as a high squealing this could indicate a fan may be failing in your
computer.
First, verify the fan on the power supply is working by examining the back of the computer and
seeing if the fan is moving and moving smoothly. For all other fans in the computer you will
need to either open the computer and verify all fans are working, e.g. processor fan and case fan.
Tip: If your BIOS monitors the RPM of the fans enter CMOS Setup and verify it does not report
any errors.

What temperature should my processor be running at?
Issue with operating system
If after following each of the above recommendations your computer still continues to reboot it
is likely that you are experiencing a Microsoft Windows operating system related issue that
cannot be explained. To help make sure this is the case try the below steps.
1. Reboot the computer and enter CMOS setup as the computer is booting.
2. After you have loaded the computer in CMOS setup let the computer sit.
If the computer does not reboot while letting the computer sit in CMOS it is likely that you are in
fact experiencing an issue with Microsoft Windows and it is recommend that if you have
followed all of the above recommendations that you reinstall Microsoft Windows.
Computer turns off without warning
Question
Computer turns off without warning.
Cause
This issue could be caused by any of the below possibilities.
1. Heat related issue.
2. Hardware issue or error.
3. Computer virus.
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4. Issue with operating system.
5. Other failing hardware
Answer
Tip: This document is for computers that remain off and not computer's that turn back on
(restart).
Caution: Some of the below steps require you open your computer. While in the computer, be
cautious of ESD.
Heat related issue
A computer that turns off without warning is usually caused by a heat related issue. Many
computers today are designed to turn off automatically if the computer, processor, or other
device gets too hot.
Start by verifying the fan on the power supply is working by examining the back of the computer
and seeing if the fan is moving and moving smoothly. For all other fans in the computer, you will
need to open the computer and make sure the fan are working. While in the computer example
the processor fan (heatsink), video card fans, and case fans. If you have heard any abnormal
noises coming from your computer recently such as a high squealing, this is also a common
indication of a fan failure.
Tip: While inside the computer it may also be a good idea to clean the inside of the computer.
Dust, dirt, hair, and other residue in the vents and on the fans can prevent proper air flow and
heat the computer.
Tip: If your BIOS monitors the RPM of the fans, enter BIOS and make sure the BIOS does not
report any errors. Software utilities such as SpeedFan can also be used to help monitor fans in
your computer.
While inside the computer, it's also a good idea to verify the processor heatsink is properly
connected by disconnecting and reconnecting the heatsink. If the processor heatsink is not
properly attached or does not have a proper amount of thermal compound, the computer will
overheat.
Caution: If you do remove the processor heatsink the thermal compound on the processor and
heatsink should be cleaned and new thermal compound should be applied. Not reapplying new
thermal compound could make issues worse since the bond between the CPU and heatsink would
be broken.


Is there a way to tell how hot my CPU is running?
What should be the temperature of my processor?
Hardware issue or error
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Any failing hardware component in your computer could cause your computer to unexpectedly
turn off without warning. If you have recently added any new hardware remove it from the
computer to make sure it is not causing the problem.
Tip: Before attempting to remove any hardware, make sure you are not encountering this issue
because of hardware conflicts by checking Device Manager for errors.
If you have not recently installed any new hardware into the computer, the next best solution to
determining if this is a hardware issue would be remove any hardware on the computer that is
not needed. For example, remove your modem, network card, sound card, and any other
expansion cards that are not needed for the computer to operate. Run the computer without these
cards to see if they are the cause of your issue.
Computer virus
Although not as likely as the above reasons, it is possible for your computer to be infected with a
virus that is designed to shut down your computer or turn it off. If your computer seems to be
turning off when executing a certain program at specific times in the day, it could be infected.
If you believe your computer may be infected with a virus or are uncertain if your computer is
infected with a virus, make sure your virus scanner definitions are up-to-date and it may also be a
good idea to scan the computer for any other malware.
Issue with operating system
If after following each of the above recommendations your computer still continues to reboot, it
is likely that you are experiencing a Microsoft Windows operating system related issue that
cannot be explained. To help make sure this is the case, try the below steps.
1. Reboot the computer and enter CMOS setup as the computer is booting.
2. After you have loaded the computer in CMOS setup, let the computer sit.
If the computer does not turn off while letting the computer sit in CMOS, you are likely
experiencing an issue with Microsoft Windows or your operating system and it is recommend
you erase everything and reinstall Microsoft Windows.
Other failing hardware
If after reinstalling your operating system, or during the installation of your operating system,
your computer turns off abnormally, it is very likely that other hardware is failing in the
computer. Often this is RAM, CPU, Motherboard, Power Supply, or Video card (in that order).
Testing my computer motherboard and CPU
for failures?
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Question
Testing my computer motherboard and CPU for failures?
Answer
A bad computer motherboard or CPU can cause an assortment of different issues on your
computer. Below are just a few of the possible issues you may encounter. It is important to
remember that the issues below can also be caused by more than just a bad motherboard and
CPU.
1. Computer does not boot, instead you get a beep code. See the POST and beep code page for
additional information about beep codes.
2. Random computer crashes causing General Protection Fault error messages, Illegal Operations,
Fatal Exceptions, etc.
3. Computer randomly reboots.
There are several different ways to test your computer's motherboard and CPU to determine if it's
bad or has flaws that are causing issues with your computer. Below is a listing of these
recommendations.
Software and Hardware solutions
Below is a listing of a software programs available that are designed to test your computer's
motherboard and CPU. However, with the complexity and wide variety of computer
motherboards and CPUs, these programs may not detect every possible failure.

Hot CPU Tester - Our software recommendation for testing a computers motherboard and CPU.
This is a great tool. Easy to run and use for looking for failures with your computer. In addition
to testing a computer, this program also includes a burn-in feature for new computers or
computers with a new motherboard or CPU.
In addition to the above solutions, there are other fantastic 100% commercial products. Below is
a listing of some of these products.



PC-doctor - A fantastic but not cheap solution often used for service centers and technicians to
diagnose computer hardware issues including motherboard issues.
PC Diagnostics - Another company that offers both hardware and software solutions for testing
the majority of the hardware in your computer including the motherboard.
Ultra-X - Another great collection of products that can help test computer hardware including
the motherboard.
Replace the motherboard and CPU
If the motherboard or CPU is bad after trying the above suggestions, we suggest replacing it.
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Laptop buying tips
Quick links
Introduction
What to look for
Brand of computer
Scams
Introduction
Purchasing a home or business laptop can be a much more confusing and sometimes frightening
experience as most users today have some experience with a desktop computer but not as many
have experience with a laptop, what is properly known as a portable computer. Portable
computers are an excellent solution for anyone who needs to be portable and have all of their
information on a small computer. Below is a listing of help and tips when considering to
purchase a laptop computer.
What to look for
When purchasing a computer, it is likely that you will have a general idea of what you may like
in the computer or how you would like to configure the computer. Below is a listing of the
various components likely to be found in a computer, and recommendations and tips when
considering any of the below components.
Device
Battery
usage
Display
Recommendation
A very important consideration for any users that need to have a working laptop on
the road or in the air. Verify when purchasing a portable computer how long the
battery lasts. Be cautious, as many manufacturers will indicate a battery usage time
but this may be at the lowest possible settings; ensure that the manufacturer clarifies
what the standard battery usage life is when using the portable computer in all power
modes.
All portable computers come with a display. While it is almost always possible to
hook up an external monitor when traveling with the laptop, the display is an
important consideration. When looking at the display, ensure it is large enough for
your needs. A very easy method of reducing the cost of the laptop is to reduce the
size of the screen, unless price is an very important consideration we highly suggest
that you purchase a laptop with at least a 12" or lager LCD and recommend an LCD
size of 14"
Complete buying tip information on Flat Panel or LCD solutions can be found on our
flat panel buying tips page.
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Drives are sometimes overlooked when considering a portable computer but can be
an important consideration. Portable computers can come with various drive
configurations, for example:



Drives
One drive bay where the CD-ROM and the Floppy drive are interchangeable.
For users who utilize the floppy drive often, this may be an issue; however,
for other users who do not utilize the floppy, this may be a more appropriate
solution as the computer will be lighter and thinner with one drive bay.
Two drive bay portable computers have a floppy solution as well as CDROM solutions. These computers will be a less expensive computer when
compared to the other solutions; however, it is the always the heaviest of all
the solutions.
No drive bay portable computers allow for a laptop to be extremely light and
utilize external drives instead of internal. Pay close attention to the price of
these laptops; while it may appear to be a portable solution, many
manufacturers will charge you an additional price for the external drives,
which will eventually be needed.
Finally, some users may also want to consider different media solutions. For
example, many laptops allow for a standard floppy drive or an LS120 drive. The
LS120 drive can read floppy diskettes and at the same time be used as a backup
storage device as it can store up to 120MB on a LS120 diskette. Additionally
consider the option of a DVD* or CD-RW drive as opposed to a CD-ROM drive.
*If you are considering a DVD solution, verify if the DVD comes with hardware or
software decoding. Hardware decoding for laptops is accomplished by using a
PCMCIA card and will add onto the overall price of the laptop.
Hard
drive
Hard drives have and always will be an important consideration to think about when
purchasing a new portable computer. Like a standard computer, the hard drive will
be the destination of all your files and information, and if that drive is to become full,
that drive will need to be replaced or another drive will need to be added to the
computer. When looking at the space of the hard drive, always get the maximum size
hard drive, considering you will eventually always run out of space.
Complete buying tip information on hard drives can be found on our hard drive
buying tips page.
Lock
Memory
Does the portable computer include any locking system? If yes, what locking system
is included? This can be very important for users who are on the road.
Memory is and has always been an important consideration when looking at
purchasing a computer. Determine the amount of memory included in the computer
as well as verify if that memory can be upgraded in the future. The more memory the
computer has, the more efficient the computer will run.
Complete buying tip information on computer memory can be found on our memory
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buying tips page.
Modem
If a modem is required, ensure that a modem is included with the portable computer.
In addition, verify if the modem is an internal or PC-CARD (PCMCIA) modem as
you may require all the available PC-CARD slots in the future. PC-CARD modems
are type II that for most computers will allow for an additional type II to be
connected.
Complete buying tips and information on modems can be found on our modem
buying tips page.
Network
card
If a network connection is required, ensure that a network card is included with the
portable computer. In addition, verify if the network card is an internal or PC-CARD
(PCMCIA) network card as you may require all the available PC-CARD slots in the
future. Network PC-CARDs are type II that for most computers will allow for an
additional type II to be connected.
Complete buying tips and information on network cards can be found on our network
card buying tips page.
The computer processor is and will always be an important consideration when
purchasing a computer. Today, with multiple CPU/Processor manufacturers, it may
be more confusing as well as more cost efficient to look at the different processors
available.
Processor
Complete buying tips and information on computer processors can be found on our
CPU buying tips page.
Sound
card
Sound cards are important when looking at purchasing a computer; however, the
majority of all computer users will find that most standard sound cards will suit their
needs. However, some users may enjoy purchasing more advanced sounds cards that
will increase the amount of speakers that can be used and in some games and
programs and the sound quality and capabilities.
When looking at the sound aspect of a portable computer, many laptops do not have
sufficient sound and will require external speakers or headphones. Ensure that the
sound quality meets your needs.
Weight
Video
card
Weight is a very important consideration when considering a portable as the
computer will be carried; the lighter the portable computer, the more easy it will be
to carry.
Video cards are becoming an extremely important factor when purchasing a
computer. While this may surprise some, a video card can make or break a computer
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when it comes to playing games on the computer. Most games today require
additional video memory as well as special video modes such as OpenGL. With a
video card with little video memory or without these modes, the computer will be
unable to play these games. In addition, the advances in video cards can dramatically
increase the user enjoyment of the game being played.
Complete buying tips and information on video cards can be found on our video card
buying tips page.
Brand of computer
When looking at purchasing a portable computer, you will likely hear different stories, some
good and some bad. Regardless if the story is good or bad, these stories are always based on the
experience of that user. While it may be true that the user had a bad or terrible experience with
that computer, all computer manufacturers have had users who have had a bad experience and
there is no such thing as a bad or perfect computer manufacturer. Below is a listing of various
things to consider when purchasing a computer, and in some cases, how to tell the good from the
bad and help allow you to purchase the portable computer that will suit your needs.
Add-ons
Some computer manufacturers may try to sell additional add-ons when
purchasing a portable computer. Unless you have done your research on the
additional add-on, do not consider the add-on. While in some cases it may be
beneficial to get a printer, scanner, camera or PC Cards with a computer, you
may be paying premium for the additional add-on, or in the case of the printer,
you may have to pay premium on the ink in the future. Do you research, ensure
that if you get an additional hardware or add-ons that the hardware will suit
your needs and that it does not end up being something that is not going to be
used.
Free add-ons? Some computer companies may entice you into purchasing a
computer by giving you free add-ons. These add-ons may be advertised as free,
however, ensure or ask if the add-on price is not just being added to the overall
computer price.
While most manufacturers today are reducing the amount of documentation
included with their computers, an excellent question, especially if the computer
is being purchased by a new computer user, is "what documentation is included
with the computer?"
Documentation All computer manufacturers will include some paper documentation or paper
inserts; however, does this information include documentation about upgrading
the computer in the future? How to connect the cables to the computer?
Documentation on how to use the software such as the additional included
software?
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Note: It is important to distinguish between paper documentation and on-line
documentation. On-line documentation, which is being found more today, is
information that is either locally on the computer or can be accessed via the
Internet. If the information is available over the Internet, see how that
information looks and if it suits your needs before purchasing the computer.
We use location to describe several different topics. First, what is the location
of where the computer is purchased: If the computer is purchased at a local
retail store, can the computer be returned to that store if unsatisfactory? If the
computer is purchased through mail order or directly through the computer
manufacturer or reseller, where can the computer be returned if unsatisfactory?
Location
Second, can the store location of where the computer was purchased service the
computer? If not where is the closest location to where the computer can be
serviced?
Third, if the computer is purchased directly from the computer manufacturer
and is shipped through mail, how is it shipped? What is the time period for the
computer to arrive to your destination? What happens if the computer is
damaged during shipping?
Refurbished is a term used to describe a computer or a hardware device or
component in a computer that has been used; however, it has been looked at and
determined to be in working order. However, because the product has been used
or purchased, it cannot be sold as new.
Refurbished
Refurbished computers will have a lower price and are a good deal for users
who may not have a lot of money to spend on a new computer. It is important,
however, to compare the price of the refurbished computer to a new computer
as well as to review all of the tips on this page as all the same rules, tricks and
tips still apply.
Service is an important consideration to look at when looking to purchase a
computer, new or used. The service is how many companies describe the repair
of a computer if it or a component within it is to become broken. Below is a
listing of what services to look for.
Service
1. Is the service onsite, meaning a technician will come to your location to
replace or fix a bad component. If the service is onsite, is it for the
complete time of the warranty?
2. If onsite is not offered, what is and for how long?
3. Can the computer be taken to a local service center? If yes, what is the
closest authorized service center?
4. What is the time frame the service takes to occur? For example, if the
computer has a bad component, what is the time it will take for a
technician to come onsite and replace that component, or what is the
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time it will take to have the computer sent in to be fixed? Finally, if that
time frame is not accomplished, what is the company willing to do?
Would they be willing to provide you with a loaned computer?
5. Because the computer is a portable computer, is International Service
available? This will allow users who may be in a different country to
have their computer fixed in that country.
Software, for many computer users especially new users, is thought to be an
important consideration when purchasing a new computer. Granted there is
software that we highly recommend looking for when purchasing a computer,
such as word processor or spread sheet program, some computer companies
may over hype the software package. Below is a listing of what to look for
when looking at the software included with a computer.
Software
1. Does the software include Microsoft Office or Corel Suite? These
packages allow you to have a word processor and a spread sheet. For the
majority of all users, this should be an important consideration.
2. Is the software full versions of the software or is the software demo
programs or shareware programs?
Support
While you can always contact Computer Hope for support, manufacturer
support for most users will be a very important consideration, as if an issue
arises with the computer, you must be able to be able to contact a support
representative. Things to consider when looking at the support options of a
computer are shown below.
1. Is support open 24 hours, 7 days a week? If not, what are the hours?
2. Is support open on holidays? If not, what days are it closed?
3. What support options are available? Phone? E-mail? Web? Chat?
While this option may not be considered at first when purchasing a computer, it
is an important consideration. Below is a listing of different options to look for
when looking to upgrade a portable computer.
Upgrade
ability
1. What can be upgraded in the computer? RAM? CPU? Hard Drive? If
available to upgrade, what are the maximum amounts or is it specified
within documentation provided with the computer?
2. Are the upgrades something that the end-user can do or does it require a
service center to install?
Finally, what warranty is offered by the computer manufacturer? How long is
the warranty? Does the warranty cover both hardware and software issues?
Warranty
Warranty can cause frustrations for most users. We highly recommend that a
computer only be considered if it has at least a one-year warranty. Many cheap
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computers will only come with a 90 day warranty; meaning if a part goes bad,
you will have to pay for the part as well as the service. This may not be an issue
for users who just need a cheap computer and are willing to replace parts and
service the computer.
Scams
Unfortunately, like anything, it is possible to be tricked or for computer companies to scam you.
Below is a listing of what to look for when purchasing a computer.

Get what you pay for - Ensure that the product you are purchasing is what you are
paying for. It has been known that computer companies may list a processor being a
specific speed but may actually have a different speed into the computer. This,
unfortunately, can be very easy as any user can 'over clock' a processor, making it appear
as one speed but in reality being a completely different speed. For example, you may buy
a 733MHz processor but instead get a 500MHz.
To determine the processor speed, open the computer and look at the processor itself. Do
not look at the processor through a software program or through BIOS as these values
can be changed or tricked.

Legal software - When purchasing a computer, ensure it comes with legal software.
Many end-users or small computer companies who build or sell computers may not
provide you with legal copies of the software, which is illegal. Verify that the software
that came with your computer is on a standard CD and not a burnt CD. A burnt or homemade CD will be a different looking CD and have a gold or green bottom. Ensure that if
the software requires a license or registration number that it was included with the
computer. An example of software that includes these certificates is Microsoft Office and
Windows.
How can I disable or enable the internal
speaker?
Question
How can I disable or enable the internal speaker?
Additional information
This document contains information about disabling the internal speaker (speaker on the
motherboard). This speaker is responsible for the beeps or beeping noises and sounds you often
hear from your computer. See the internal speaker definition for additional information about this
term.
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If you are looking for information and help about external speakers see the speaker page.
Answer
The answer to this question depends on the motherboard, its configuration, and the software you
have installed in the computer.
Disabling the internal speaker
Software
Motherboard jumper
Motherboard cable
Software
If you're running Microsoft Windows you can disable the Internal speaker or PC speaker by
following the below steps.
1.
2.
3.
4.
5.
6.
Open Device Manager
In Device Manager click View and click "Show hidden devices"
This should make "Non-Plug and Play Drivers" visible in Device Manager.
Expand Non-Plug and Play Drivers by clicking the plus and double-click Beep.
Within the "Beep properties" window click the Driver tab.
Under the driver tab if you wish to temporarily disable this device click the Stop button. If you
wish to permanently disable this device under the Startup type select Disabled.
Motherboard jumper
If following the above steps does not disable the Internal speaker you can also almost always
disable the Internal speaker through jumpers on the motherboard. Many motherboard
manufacturers have jumpers that when jumped or not jumped will enable the onboard speaker.
Unfortunately all motherboards are different, therefore you will need to refer to the motherboard
documentation in order to determine if your motherboard has such a jumper and what to set it to.
Motherboard cable
Some motherboards do not have an onboard speaker and instead use a computer case speaker
that can be removed to disable the speaker. Unfortunately again you will need to refer to the
motherboard or computers documentation to determine if your computer is setup this way.
Enabling the internal speaker
Software
Motherboard jumper
Motherboard cable
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Software
If you are running Microsoft Windows you can enable the Internal Speaker or PC speaker by
following the below steps.
1.
2.
3.
4.
5.
6.
Open Device Manager
In Device Manager click View and click Show hidden devices
This should make "Non-Plug and Play Drivers" visible in Device Manager.
Expand Non-Plug and Play Drivers by clicking the plus and double-click Beep.
Within the "Beep properties" window click the Driver tab.
Under the driver tab if you wish to temporarily enable this device click the Start button. If you
wish to permanently enable this device under the Startup type select System.
Motherboard jumper
If following the above steps does not enable the Internal speaker you can also almost always
enable the Internal speaker through jumpers on the motherboard. Many motherboard
manufacturers have jumpers that when jumped or not jumped will disable the onboard speaker.
Unfortunately all motherboards are different, therefore you will need to refer to the motherboard
documentation in order to determine if your motherboard has such a jumper and what to set it to.
Motherboard cable
Some motherboards do not have an onboard speaker and instead use a computer case speaker
that can be removed to disable the speaker. Unfortunately again you will need to refer to the
motherboard or computers documentation to determine if your computer is setup this way.
How to clear an unknown BIOS or CMOS
password
Question
How to clear an unknown BIOS or CMOS password.
Answer
Tip: The below steps are for a desktop computer and do not include steps on how to clear a
laptop CMOS password.
If you encounter a password prompt at boot or the BIOS or CMOS setup is locked as shown
below and you do not know the password you will need to clear the BIOS password using the
suggestions listed below.
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Clear using jumper (recommended)
Caution: When inside the computer be sure you're aware of the potential damage that can be
caused by ESD.
On the computer motherboard locate the BIOS clear or password
jumper or dip switch and change its position. This jumper is often labeled CLEAR, CLEAR
CMOS, JCMOS1, CLR, CLRPWD, PASSWD, PASSWORD, PSWD or PWD as shown in the
picture to the right. To change the jumper remove it from the two pins its currently on so that it
covers the pin that is not covered. For example, in the picture to the right pins 1 and 2 are
covered, you'd remove the jumper and put it on pins 2 and 3.
Once this jumper has been changed, turn on the computer and the password should be cleared.
Once cleared, turn the computer off and return the jumper or dip switch to its original position.
The location of the jumpers or dip switches are dependent on the manufacturer of the computer
and motherboard. However, below are some general ideas on where to find it. Remember that
most motherboards could have dozens of different jumpers, make sure you're changing the
CMOS jumper and not something else. If these general suggestions do not help refer to your
motherboard or computer documentation or skip to the next step.
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1. On the edge of the motherboard - Most jumpers are located on the side of the motherboard for
easy accessibility, verify by looking at all visible edges of the motherboard.
2. By the CMOS battery - Some manufactures will place the jumper to clear the CMOS or BIOS
password by the actual CMOS battery.
3. By the processor - Some manufactures will place the jumpers by the processor of the computer.
4. Under the keyboard or bottom of laptop - If you are working on a laptop computer the location
of the dip switch (almost never a jumper) can be under the keyboard or on the bottom of the
laptop in a compartment such as the memory compartment.
5. Other visible location - While it is possible that the jumpers or dip switches may not be in a
visible location, most manufactures try to make things easier by placing the jumpers or dip
switches in another visible location.
Generic passwords
Try using generic CMOS passwords. Note: many of these generic passwords are no longer used
or only used with older computers.
Use a BIOS password utility
There are utilities designed to help bypass CMOS passwords. An example of a great utility to
decrypt or bypass BIOS passwords is the PC BIOS Security and Maintenance toolkit.
Remove CMOS battery
Removing the CMOS battery like the one shown in the picture
to the right will cause the system to lose all CMOS settings including the password. To do this
locate and remove the CMOS battery on the motherboard for at least five-minutes. After this has
been done put the battery back into the computer and turn it back on.
Jump the CMOS solder beads
Older computers and especially older laptops don't have jumpers or dip switches and require the
user to jump a pair of solder beads on a circuit board. The identification and location of these
solder beads can vary and if not available in computer documentation is only obtainable through
the computer manufacturer.
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If you've identified the solder beads they can be jumped by placing a flat-head screwdriver over
the two beads and leaving it on those beads while turning on the computer. Once the computer
has booted turn off the computer and then removes the screwdriver.
Contact manufacturer
If the above solutions do not help or you are unable to locate the jumpers or solder beads, it's
recommended you contact the computer manufacturer or motherboard manufacturer for the steps
on clearing the computer password.
http://www.computerhope.com
1. From what location are the 1st computer instructions available on boot up?
A.ROM BIOS
B. CPU
C. boot.ini
D.CONFIG.SYS
E. None of the above
2. What could cause a fixed disk error.
A.No-CD installed
B. bad ram
C. slow processor
D.Incorrect CMOS settings
E. None of the above
3. Missing slot covers on a computer can cause?
A.over heat
B. power surges
C. EMI.
D.incomplete path for ESD
E. None of the above
4. When installing PCI NICS you can check the IRQ availability by looking at
A.dip switches
B. CONFIG.SYS
C. jumper settings
D.motherboard BIOS
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E. None of the above
5. With respect to a network interface card, the term 10/100 refers to
A.protocol speed
B. a fiber speed
C. megabits per seconds
D.minimum and maximum server speed
E. None of the above
http://www.indiabix.com/computer-science/computer-hardware/
6. Which Motherboard form factor uses one 20 pin connector
A.ATX
B. AT
C. BABY AT
D.All of the above
E. None of the above
7. A hard disk is divided into tracks which are further subdivided into:
A.clusters
B. sectors
C. vectors
D.heads
E. None of the above
8. A wrist grounding strap contains which of the following:
A.Surge protector
B. Capacitor
C. Voltmeter
D.Resistor
E. None of the above
9. Which standard govern parallel communications?
A.RS232
B. RS-232a
C. CAT 5
D.IEEE 1284
E. None of the above
10. In laser printer technology, what happens during the conditioning stage?
A.The corona wire places a uniform positive charge on the paper
B. A uniform negative charge is placed on the photosensitive drum
C. A uniform negative charge is placed on the toner
D.All of the above
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E. None of the above
11. What product is used to clean smudged keys on a keyboard?
A.TMC solvent
B. Silicone spray
C. Denatured alcohol
D.All-purpose cleaner
E. None of the above
12. ESD would cause the most damage to which component?
A.Power supply
B. Expansion board
C. Monitor
D.Keyboard
E. None of the above
13. To view any currently running Terminate Stay Resident (TSR's) programs you could type:
A.Memory
B. MEM
C. SYS /M
D.Memmaker
E. None of the above
14. Which type of system board is the MOST likely candidate for processor upgrading if you
want maximum performance and future compatibility?
A.ML
B. PCI
C. ISA
D.EISA
E. None of the above
15. Suppose that you have a the maintenance package identifies several possible field replaceable
units (FRUs) that will resolve the problem. What should you do after turning the power off?
Replace the indicated parts, one at a time in the recommended sequence, until the problem
A.
is resolved; return unused FRUs to stock
Replace all of the indicated FRUs at once and return the machine to the customer if the
B.
problem is resolved
Follow the same procedure as in ays replace the system board first if it is on the list of
C. possible FRUs If multiple FRUs are indicated, then software is the most likely source of
the problem
D.None of the above
16. Most PCs give a single beep on bootup to indicate they are ok hardware wise. You boot your
PC and don't get a beep. What should you check first?
A.system board
B. RAM
C. microprocessor
D.power supply
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E. speaker
17. Which peripheral port provides the FASTEST throughput to laser printers?
A.RS-232
B. SCSI
C. Parallel
D.Serial
E. None of the above
18. The mouse pointer moves erratically, what is the possible cause? The mouse
A.ball is dirty
B. is not connected
C. driver is not installed properly
D.has an incorrect IRQ setting
E. None of the above
19. Voltage4s measured:
A.in parallel
B. in series
C. after breaking the circuit
D.after checking resistance
E. after checking current
20. Your customer tells you the print quality of their dot matrix printer is light then dark. Which
of the following could cause the problem.
A.Paper slippage
B. Improper ribbon advancement
C. Paper thickness
D.Head position
E. None of the above
21. The 34-pin connection on an I/O card is for?
A.Floppy drive
B. SCSI drive
C. IDE drive
D.Zip drive
E. None of the above
22. The terms "red book", "yellow book", and "orange book" refer to:
A.SCSI
B. ide
C. floppy drive technology
D.CD-ROM standards
E. All of the above
23. On the 16-bit ISA bus, IRQ2 is elevated to which higher level Interrupt?
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A.9
B. 11
C. 13
D.15
E. None of the above
24. What beep codes could indicate a system board or power supply failure?
A.steady short beep
B. no beep
C. one long continuous beep tone
D.steady long beeps
E. All of the above
25. To view any currently running Terminate Stay Resident (TSR's) programs you could type:
A.Memory
B. MEM
C. SYS /M
D.Memmaker
E. None of the above
26. Which part of the laser printer should NOT be exposed to sunlight?
A.Transfer corona assembly
B. PC drum
C. Primary corona wire
D.Toner cartridge
E. None of the above
27. After doing a low-level format, what would be the next step in configuring the hard drive in a
system?
A.Format DOS partition
B. Install operating system
C. Configure DMA channel and back-up interrupt
D.Partition had disk
E. None of the above
28. Resistance is measured in ?
A.Volts
B. Amps
C. Watts
D.Ohms
E. None of the above
29. What command is used to reset a MODEM when using the "AT Command Set"?
A.ATR
B. ATZ
C. DTR
D.DCE
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E. None of the above
30. When installing a SCSI CD-ROM drive, you must set the CD-ROM SCSI adapter to:
A.B0007
B. An unused SCSI address
C. The same address as the SCSI device before the CD-ROM
D.SCSI ID=1
E. None of the above
31. Pick the correct choice for the 80386SXCPU.
A.16 bit word size, 16 bit data path
B. 32 bit word size, 16 bit data path
C. 8 bit word size, 32 bit data path
D.32 bit word size, 8 bit data path
E. 32 bit word size, 32 bit data path
32. In Inkjet technology the droplets of ink are deflected by?
A.multi directional nozzles
B. electronically charged plates
C. high pressure plates
D.electro static absorbtion
E. None of the above
33. When your hard drive crashes from any of the correct selections in the question above, or
from dropping it, it is known as head-to-disk interference, or HDL
A.True
B.False
34. What tool is used to test serial and parallel ports?
A.high volt probe
B. cable scanner
C. loop backs (wrap plugs)
D.sniffer
E. None of the above
35. ESD would cause the most damage to which component?
A.Power supply
B. Expansion board
C. Monitor
D.Keyboard
E. None of the above
36. What is the highest binary number that can be referred to on a three position jumper block?
A.4
B. 6
C. F
D.1
E. None of the above
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37. What voltage does a Pentium system use?
A.+12 volts
B. + 5 volts
C. + 8 volts
D.+3.3 volts
E. None of the above
38. A numeric error code check: A 17xx indicates a problem with:
A.CMOS
B. ROM BIOS
C. DMA controller
D.hard drive or controller
E. power supply
39. Which provides the fastest access to large video files?
A.Optical drives
B. IDE hard drives
C. SCSI hard drives
D.EIDE hard drives
E. None of the above
40. A 25-pin female connector on the back of your computer will typically be:
A.Serial port 1
B. A parallel port
C. Docking
D.COM2 port
E. None of the above
41. On the PC side, the printer port is a:
A.25 pin female serial connector
B. 15 pin female parallel connector
C. 25 pin male serial connector
D.15 pin female serial connector
E. 25 pin female parallel connector
42. You were installing an application in Windows 95, and the computer crashes, what do you
do?
A.press alt + Ctrl + delete, twice
B. press alt + Ctrl + delete, and end task
C. press the reset button on the computer
D.turn off computer and boot from a floppy disk
E. None of the above
43. RS-232 is a standard that applies to:
A.serial ports
B. parallel ports
C. game ports
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D.networks
E. digital frequencies
44. You just installed a new IDE hard drive, but your system BIOS will not recognize the new
drive, what should you check first.
A.cable sequence
B. jumpers on the hard drive
C. drivers that need to be loaded
D.hard drive manufacturer web site information
E. None of the above
45. During boot-up, the memory test:
A.Is a superfluous step that should be ignored
B. Checks and verifies that contiguous memory is installed
C. Is an operational error
D.Displays what memory is installed, but nothing else
E. None of the above
46. What is the best ground for a conductive work bench?
A.AC outlet
B. Ground to bend
C. To another device
D.Chassis ground
E. None of the above
47. Topically, how many type III PC cards can you insert in a laptop
A.1
B. 2
C. 3
D.4
E. None of the above
48. What is the first thing you could do to check for damage to a printer after receiving it?
A.Run MSD diagnostics
B. Attach it to a PC and print something
C. Check the cables
D.Unbox it and examine it for physical damage
E. None of the above
49. You have a system that periodically locks up. You have ruled out software, and now suspect
that it is hardware. What should you do first that could help you narrow it down to the
component at fault?
A.rotate the RAM
B. replace the RAM
C. replace the level 2 cache SIMM
D.disable the CPU cache in CMOS
E. replace the CPU
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