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MIKE MEYERS PRESENTS
PRESENTS::
Computer Literacy
Your Ticket to IC3 Certification
SCOTT JERNIGAN
ELKS
Learning
12929 Gulf Freeway, Suite 105
Houston, Texas 77034
U.S.A.
Publisher
Dudley Lehmer
Editor in Chief
Scott Jernigan
Technical Editors
Martin Acuña, Dudley
Lehmer, Mike Meyers
Simulation Developers
Dudley Lehmer, Janelle
Meyers, Michael Smyer
Computer Literacy – Your Ticket to IC3 Certification
Scott Jernigan
ELKS Learning
12929 Gulf Freeway, Suite 105
Houston, Texas 77009
U.S.A.
To arrange bulk purchase discounts for sales promotions, premiums, or
fund-raisers, please contact ELKS Learning at the address above.
Computer Literacy – Your Ticket to IC3 Certification
Contributors
Martin Acuña
Cindy Clayton
Cary Dier
Tina Ferguson
Jane Holcomb
Libby Ingrassia
Dudley Lehmer
Mike Meyers
Jessica Stratton
Copyright © 2005 by ELKS Learning. All rights reserved. Printed in the
United States of America. Except as permitted under the Copyright Act
of 1976, no part of this publication may be reproduced or distributed in
any form or by any means, or stored in a database or retrieval system,
without the prior written permission of publisher, with the exception
that the program listings may be entered, stored, and executed in a
computer system, but they may not be reproduced for publication.
Peer Reviewers
Kris Donnelly-Sasser
Jennifer Passman
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Copy Editors
Cindy Clayton, Cary Dier
Indexer
Cindy Clayton
Book p/n 1234567890 and CD p/n 1234567890
parts of
ISBN 0-9768422-0-3
Composition
Donette Reil
Illustrator
Michael Smyer
Cover Design
Donette Reil, Kathy Yale
This book was composed
with Adobe PageMaker and
Adobe InDesign
Information has been obtained by ELKS Learning from sources believed to be
reliable. However, because of the possibility of human or mechanical error by our
sources, ELKS Learning, or others, ELKS Learning does not guarantee the accuracy,
adequacy, or completeness of any information and is not responsible for any errors
or omissions or the results obtained from the use of such information.
About the Author
Scott Jernigan wields a mighty red pen as Editor in Chief for Total Seminars. With an
M.A. in Medieval History, Scott feels as much at home in the musty archives of London
as he does in the warm CRT glow of Total Seminars’ Houston headquarters.
Scott has edited and contributed to more than a dozen books on computer literacy,
hardware, operating systems, networking, and certification, including co-authoring
the best-selling All-in-One A+ Certification Exam Guide, 5th edition, and the A+ Guide to
Managing and Troubleshooting PCs (both with Mike Meyers).
Scott has taught all over the United States, including stints at the United Nations
in New York and the FBI Academy in Quantico. He is an A+ and Network+ certified
technician, a Microsoft Certified Professional, a Microsoft Office Specialist, and, of
course, Certiport Internet and Computing Core Certified.
About Mike Meyers
Mike Meyers is the best-selling author of numerous books on computer literacy and
certifications, including Introduction to PC Hardware and Troubleshooting, and the Allin-One A+ Certification Exam Guide. Mike is considered the industry expert on computer certifications.
Acknowledgments
Many people helped put this book together, and I could not have done Computer Literacy
without them. The folks listed as Contributors put soul and time into writing, editing,
and researching. Thank you.
Cindy Clayton pushed for this project for months. The addition of the delightful
Audrey Clayton added extra gurgles to her outstanding editing and writing on this
book.
Martin Acuña put the indelible stamp of his personality on the book, from his
excellent writing and editing to the fun movie theme. It was great to work with you,
my friend.
My publisher, Dudley Lehmer, gave me the encouragement to continue and go
through the book-birthing pains, knowing the end result would be something worthy
for so many people.
Jenny Passman gave (and continues to give) fantastic feedback from the trenches,
as she taught with this book as I wrote the chapters. A peer reviewer par excellence,
Jenny’s critiques and praise made this a much better book.
A hearty thanks goes out to the folks at Desktop and Press in Houston. Donette
Reil did an outstanding job designing and implementing the layout of the book. Don
Carpenter gave us superb advice on the publishing end of things.
Michael Smyer once again proved to be a sparkplug in the book-writing process.
His photographs give this book life and he proved to be a master of the illustration.
He consistently challenges me on technology, which, frankly, keeps me honest. Superb
job, Michael!
My dear friend Mike Meyers provided a swift kick in the pants when I needed it
and proved a worthy companion for many a late-afternoon gaming session to blow
off steam.
Kathy Yale, Marketing Director for ELKS Learning and Total Seminars, provided
endless enthusiasm for this project. Every time I talked with her I came away
reinvigorated and ready to tackle the next chapter or challenge. She proved to be
invaluable for getting this book from conceptualization to print.
My long-time right hand, Cary Dier, came in at the 11th hour to help finish off this
book. I indebted to her and very thankful. You’re the best, my friend.
A special thanks to Kris Donnelly-Sasser who gave me some great feedback in
the early stages of this book.
To my superb colleagues at Total Seminars, thanks for your work and support.
Janelle Meyers did amazing stuff with the simulations. Roger Conrad and David
Dussé back me up to the point that I couldn’t get my job done without them—and
they excel in their own jobs too!
Finally, to my wife, Katie, and my children, Maggie and Simon: Thank you for
being there for me. I love you.
Dedication
This book is for my daughter,
Maggie: your joy for learning
inspires me and your laughter
makes my heart lighter. I love
you and look forward to
reading this book with you.
About This Book
The Right Tools for Today
Almost every skilled job today requires employees
to use computers, so computer literacy is simply
something that every person should possess. You
need to know how computers work and how to
perform basic tasks with word processing,
spreadsheets, presentation software, and Internet
browsers. Scott Jernigan’s Computer Literacy puts
these skills into students’ hands, creating the
foundation they need for success today.
Off the Script! sidebars
provide interesting and often
fun information that relates
to the text students are
reading, but diverges from
the primary topic.
Linux on the Inside
IBM PC-based Microcomputer
Servers
The most common
microcomputer, as you
know from Part 1 of this
book, is based on the
original IBM x86
architecture. The servers
in this family use Intel or AMD
processors, sport gigabytes of DDR RAM, and have multiple hard drives
to supply safety for your data if one of the drives fails. They’re commonly
referred to as personal computers (PCs). You’ll find server PCs in two basic
physical shapes: tower and rack-mounted. Towers slip under a desk or
hide in a closet somewhere, acting pretty much like a glorified client PC.
Rack mount servers live in closets, generally affixed to a rack along side
other rack mounted servers (Figure 1.11).
Figure 11: Rack mounted server
(Photo courtesy of General
Technics)
Microsoft makes several
versions of Windows
designed to run on x86 server
PCs (Figure 1.12). Each version offers support
for multiple client computers, multiple CPUs, and gobs of RAM.
The primary differences are in scale: Windows Server 2003 works for
small businesses, for example, whereas larger businesses would want to
use Windows Server 2003 Enterprise Edition.
Figure 12: Windows Server 2003
Apple Microcomputer Servers
Apple makes a version of its popular
Macintosh hardware and operating
system designed specifically for
servers, called Xserve (Figure 1.13).
Xserve servers use Motorola and IBM
G5 CPUs and, like Windows servers,
can have multiple processors, gobs of
RAM, and tons of hard drive space.
Apple Xserve server systems run a
server-class version of Mac OS X called,
appropriately, OS X Server. Apple
Xserve servers support Macintosh,
Windows, and Linux clients.
Workstations
A workstation is a powerful
single-user computer that is
similar to a personal computer,
except that it has a more
powerful microprocessor and a
higher-quality monitor. It is used
for desktop publishing and
engineering applications, and on
jobs that require high quality
graphics more so than extensive
computing power. Workstations
are considered to be between
minicomputers and personal
computers. The better personal
computers are equal to lower-end
workstations, and the better
workstations are equal to
minicomputers.
Just to add a little confusion
to your day, you’ll also hear
the term workstation used
generically to describe a place
where people sit and work on
computers.
Figure 21.13: Apple Xserve G5
(Photo courtesy of Apple)
There are many versions of
Linux, called distributions or
distros, such as Fedora Linux,
Mandrake Linux, and SuSE.
Different companies create the
distros and make their money
in documentation and support.
Because Linux is free but
complicated, most companies
that use any version of Linux
opt for one of the supported
ones.
Discovering Rack
Mounts
Rack mounted servers don’t sit
on the floor like a typical server
and they come in quite a variety.
Surf on over to General
Technics’ Web site
(www.gtweb.net) and check out
their server cases. What’s the
difference between a 1U and a
4U? What sort of hardware
would you put in the server?
What other rack mounted
network components can you
find?
CHAPTER 1: NETWORK BASICS
Real World Computer Literacy
This book offers students an overview of the
current state of computing in the workplace,
not just focusing only on exam topics.
Students will read about and understand the
latest technology and applications.
7
Linux is the odd duck operating system, because you can run it on IBMstyle PCs, Xserve G5 machines, and most mainframes! Linus Torvalds, a
programmer from Finland, created the first version of Linux. Have you
ever complained that you didn’t like something, such as the dinner that
one of your parents made for you, and they said, “Well, why don’t you
go make your own dinner?” Well, Linus didn’t like any of the computer
operating systems in use, so he made his own. He wrote the computer
code for an operating system based on UNIX, posted it on the Internet,
and told other programmers that if they could make it better, they
were welcome to do so. Tens of thousands of programmers have made
improvements, and Linux is one of the largest collaborative projects
in the history of the world. Linux can run on just about any computer, plus
it’s free, so it has become very popular (Figure 21.14).
UNIX
Linux can run on PCs and
Macs alike.
The UNIX family of operating systems grew up in the heyday of mainframe
and minicomputers, and continues to thrive on x86-based microcomputers.
Dozens of versions of UNIX run on server computers, but the most popular
(aside from Linux and Mac OS X, both of which are based on UNIX) are
*BSD, IBM AIX, and Solaris (Figure 21.15). In look and feel, most versions
of UNIX work like Linux, so most people today lump the two families
together.
Creating Your Network
So now you’ve got a server and a
couple of clients. What’s next? I
want to access the information on
the server from one of the client
computers. In short, I want a
network! To create a network,
you need to connect a client
computer with a server in some
way. Most often, you’ll use a
wire, but you could do it
through radio waves to
create a wireless connection.
Let’s look at two common
types of networks, then
turn to network hardware.
Network Types
Figure 21.14:
Linux server
Networks come in many sizes and vary a lot in the number of computers
attached to them. Some people connect two computers in their house so
that they can share files and play games together—the smallest network
you can have. Some companies have thousands of employees in dozens of
countries, in contrast, and need to network their computers together to get
work done. Network folks put most networks into one of two categories:
LANs and WANs.
434
▲
▲
Figure 10: Typical server –
Hey! That looks like my PC!
(Photo courtesy of Dell)
Lavish and Appealing
Each chapter contains many highquality photographs, screen shots,
and illustrations that help students
assimilate the material to become
computer literate.
COMPUTER LITERACY: YOUR TICKET TO IC3 CERTIFICATION
Action! exercises prompt
the students to try out
the skills they’re reading
about or challenge them
to go deeper into a
technology.
Notes and Exam Tips
keep students focused
on essential
information and
provide insight into
the IC3 exams.
Concepts and Concrete Examples
Scott Jernigan’s Computer Literacy explains the
concepts behind technology and then goes the next
major step by providing real-world, concrete
examples of how to use the technology. Students
come away from the book with knowledge about
today’s world and also with the information needed
to take and pass the Certiport IC3 exams.
The CD-ROM in the back of the book comes with
a complete set of simulations for each chapter. The
students can walk through every step to perform
essential tasks in Windows, Word, Excel,
PowerPoint, Outlook, and Internet Explorer.
Proven Style
same approach, teaching students what they need to
know at the same time as why the information is
important. The writing is folksy rather than formal,
and motivates the students to learn. Computer Literacy
is not your usual dry, boring computer book!
What’s My Motivation? Elements
provide students with real-world
examples of technology in action, so
they understand not just the
information they’re reading but why
it’s important in the real world.
Servers and Clients
•
Details, details,
details!
Network Machines
Getting into the details of how
networks work might seem a bit
on the geeky side for a lot of
you, but try it out. Networks are
great, but they don’t do much
for you when they don’t work.
Knowing the process behind the
network enables you to
troubleshoot when something’s
wrong.’‘I’ll just call a tech if the
network’s down.’ Good thought,
but what if no tech can get to
your network before you
absolutely have to have the term
paper stored on the server and
you can’t get in? Learn the
process for your self-preservation!
•
•
Networking Process
Once you’ve assembled the pieces for a network, you can sit down at a
client computer and access a file on a server. As cool as they may seem,
networks aren’t magic. A whole bunch of stuff happens in the background
when you access network resources. Let’s look at that process now.
Johan has a slick new Windows XP laptop and wants to access an MP3
music file on his friend Maria’s computer. Two things need to be in place
before anything else happens. Both Johan and Maria’s computers need to
be connected to the same network, and Maria needs to share the folder that
holds the MP3 file.
The connection part should be easily implemented. If both computers
have Ethernet NICs, they can plug them into two ports on a switch or hub.
Sharing requires Maria to share and set permissions on her share to allow
Johan to access it. Permissions define what a user can do with a particular
shared file or folder, such as read it, delete it, and so on. How you share and
set permissions varies among the various operating systems. In Windows
XP, for example, Maria would open My Computer, right-click on the folder
containing her MP3 file, and select Sharing and Security to open the folder’s
Properties dialog box (Figure 1.20).
By default, nothing is shared, so Maria would need to select the Share
this folder radio button and give it a share name, such as Music (Figure
1.21). The default permission on a new share in Windows XP gives what’s
called’“Read” access to everyone who has access to the share. Click on the
Permissions button to open the Permissions dialog box and you’ll see what
I mean (Figure 1.22).
▲
You’ll find two types of computers in most
networks, servers and clients. Servers
manage network resources (such as
printers), provide central storage of files, and
provide services for the users (such as having
the e-mail server send your e-mail). Clients
access those shared resources.
Clients on a network are generally
microcomputers running Windows or Mac
OS, although you’ll run into Linux clients
from time to time. Other devices, such as
PDAs and mobile phones can be clients as
well.
Server computers come in quite a variety,
from supercomputers, mainframes, and
minicomputers, all the way down to
microcomputers. The operating systems
vary for servers as well, with many
companies making versions of Linux and
UNIX; Microsoft has several server-specific
versions of Windows, such as Windows
Server 2003, and Apple has a version of the
Mac OS dedicated to serving, the
appropriately named Macintosh OS X
Server.
•
•
Benefits, Risks, and Security
•
Creating Your Network
•
Sharing
You’ve seen sharing before, way
back in Part I, Chapter 1,
“Field Guide to Identifying
Computers in the Wild.” Glance
back at that chapter and answer
these questions: what can you
share on a network? What is
distributed computing and how
does that compare with network
sharing here? Would Johan and
Maria’s network benefit from
clusters?
•
•
CHAPTER 1: NETWORK BASICS
Motivational and Entertaining
Written in an engaging, approachable
writing style, Computer Literacy will grab
and hold the attention of the readers.
Knowing why they’re learning something
helps focus attention and makes learning
topics much easier.
Networks come in a couple of types,
including local area networks (LANs) that
usually involve only a few computers, to
wide area networks (WANs) that are
composed of multiple LANs. The Internet is
the biggest WAN of them all.
Computers connect to a network in one of
three ways: directly wired to a LAN via a
cable from the computer to a LAN port,
wirelessly to the LAN, and via a telephone
line, what’s called dial-up networking. A
typical network client has a network
interface card (NIC) that connects to an
Ethernet cable that connects to a central
switch.
The Ethernet standard defines everything
about modern network hardware, from the
physical size and shape of the RJ-45
connector on the end of the network cable
to the electrical signaling that enables a NIC
to break a message down into little pieces,
11
send them across the cable, and have the
receiving NIC reassemble the pieces
into a useful message.
Wireless networks use infrared or radio
waves to connect to a network. Most
WiFi networks use a combination
switch and wireless access point to
enable connectivity.
Modems enable computers to use
regular analog phone lines to call in and
connect to a network. Modems take
digital signals and transform them into
analog signals; receiving modems do
the same process in reverse.
•
•
Networks offer many benefits over
standalone computing, such as
communication, collaboration, sharing,
cost, and centralized management.
Networks enable you to exchange
information via e-mail and to work
remotely on projects with other people.
You can share files and folders on
networks, and lower costs by
centralizing some machines, such as a
shared server. Finally, central
management of networked computers
can enhance security.
Networking computers together
certainly adds both cost and risks.
Dedicated server machines, cabling,
and other network hardware can set
you back; plus you have human cost for
administration, maintenance, and
troubleshooting. Sharing opens the door
for thieves and hackers; being on the
Internet makes you more susceptible to
viruses and hacking as well.
Security
measures
must
be
implemented on networks. You can
encrypt data, require passwords and
login, thus authenticating and
authorizing a particular user to access
specific things on the network.
Applying the Principle of Least Access
(PoLA) to all users makes a lot of sense.
Give users only the access that they
need and not a drop more.
CHAPTER 1: PART 3 – SUMMARY
write the rest of this book in Esperanto, that might make it a little difficult
for you to get much knowledge about the Internet, e-mail, and other topics
we have to cover. (Unless, of course, you read Esperanto!) By writing in
English with Roman characters in a font that’s legible, in contrast, you can
enjoy the information that I’m sharing and bask in the splendor of the
magnificent prose that I modestly present. Networks require the same
consistency of language and
technology.
The Ethernet standard defines
everything about modern network
hardware, from the physical size and
shape of the connector on the end of
the network cable—called an RJ-45, if
you’re curious—to the electrical
signaling that enables a NIC to break a
message down into little pieces, send
Figure 19: Ethernet connection close-up
them across the cable, and have the
receiving NIC reassemble the pieces
into a useful message (Figure 1.19). If two machines do not have the same
kind of networking technology—a common problem in the early days of
computer networks—then they can’t network together. I won’t bore you
with a list of all the networking technologies that have had a brief moment
of glory and market share in the past. Suffice it to say that today, Ethernet
is king.
Outstanding Tools for Educators
Each chapter finishes with a Chapter Review that
not only provides a detailed summary, but also
questions on key terms, a multiple choice quiz,
essays that challenge students’ writing skills,
and projects for them to accomplish both in
class and on their own.
▲
Scott Jernigan and Total Seminars have proven with
numerous best-selling books by Mike Meyers, Scott
Jernigan, Martin Acuña, and others, and outstanding
classroom experiences, that they can reach students
at a fundamental level. Computer Literacy takes the
CHAPTER 1: NETWORK BASICS
Take Two! questions help students
put together information from
multiple parts of the book,
challenging them to remember
earlier lessons and integrate the
knowledge with the current lesson.
21
Chapter Review portions of each
chapter provide a detailed summary,
quizzes, essays, and projects for the
students to tackle, both on their own
and with the guidance of their
instructors.
Each chapter includes…
• Exam objectives that show the student the subjects they should
learn
• High-resolution photographs of important computer components
• Screen captures for quick reference to subjects discussed
• Illustrations demonstrating key points
• Action! and Take Two! sidebars that walk the students through
important processes and enhance critical thinking skills
• What’s My Motivation! sidebars that help students understand why
something that seems trivial has relevance to the real world
• Exam Tips and Notes to provide assistance and insightful information
• Summary of the important information in the chapter
• Key term list and a fill-in-the-blanks key term quiz
• Multiple choice exam (on the CD-ROM)
• Essay questions challenging students to write about the chapter content (on
the CD-ROM)
• Projects for the students to complete in class and at home (on the CD-ROM)
• Software simulations (on the CD-ROM) that walk the students through every
step in performing fundamental tasks covered in that chapter
“You must feel the Force around you; here, between you, me, the tree, the
rock, everywhere, yes. Even between the land and the ship.”
– Yoda, The Empire Strikes Back
This chapter covers the following IC3 exam objectives:
■ IC3-1
1.1.4
Identify the role of the central processing unit
■ IC3-1
1.1.6
Identify the role of types of memory and storage and the
purpose of each
■ IC3-1
1.1.8
Identify the flow of information between storage devices
to the microprocessor and RAM in relation to everyday
computer operations
■ IC3-1
1.2.1
Identify the types and purposes of external computer
components
■ IC3-1
1.2.2
Identify the types and purposes of internal computer
components
■ IC3-1
1.2.3
Identify the types and purposes of specialized input
devices
■ IC3-1
1.2.4
Identify the types and purposes of specialized output
devices
■ IC3-1
1.2.6
Identify ports used to connect input and output devices
to a computer
■ IC3-1
2.1.1
Identify how hardware and software interact
From the time you start your computer in the morning to the time you shut
it down, you move data from one place to another. You input data using
your keyboard and mouse; you download files from the Internet; you install
software from CDs and DVDs. Each time you perform any of these actions,
you move data between the many hardware components of your PC.
The data flow follows three major phases: startup—where you provide electricity to the computer and the operating system loads; primary interaction, or
what I like to call the dance phase—where you play a game, do word processing,
save your work so you can use it later; the bulk of your time on the computer
happens in this phase; and shutdown—where you close the program you’re
working in and log off or shut the computer down completely.
CHAPTER 2: GOING WITH THE DATA FLOW
Going with the Data Flow
CHAPTER 2: GOING WITH THE DATA FLOW
19
Phase One: Start Me Up! – The Computer’s Boot
Process
Boot Hill
The term boot is short for
bootstrap, as in “pulling yourself
up by your bootstraps.” Techs
adopted this term a long time
ago to describe the computer
startup process. There are two
kinds of booting, a cold boot and
a warm boot. Cold booting the
computer means turning it on
after it has been completely shut
down with the power turned off.
Warm booting means restarting
a computer that is running.
Let’s take it from Act 1, Scene 1. What happens when you press the power
button on your computer? The short answer is that the computer system
starts up, or in geek speak, it boots.
The startup process has three overlapping phases: first is the poweron phase, then the hardware test, followed by the operating system load
phase.
Power-on
The power-on phase takes place immediately after you press the power
button. Electricity goes into the power supply—hardware that converts AC
electricity from your power outlet into DC power that computers use—
and from there to the drives and motherboard, waking the CPU. The CPU
then wakes the system’s read-only memory—basic input/output system (ROMBIOS) memory circuit. The ROM-BIOS chip stores the computer’s “lizard
brain,” its most basic commands and programs, including the collection of
the hardware test phase diagnostic programs. Figure 2.1 shows a typical
power supply; Figure 2.2 shows a ROM- BIOS chip on a motherboard.
Figure 2.2: ROM-BIOS chip
Hardware Test
Figure 2.1: Power supply
Once the ROM-BIOS wakes up,
the computer runs basic
hardware tests, asking the
important hardware components to identify themselves and
report their status (usually
accompanied by beeps and
bloops and blinking lights). If
there is a problem with one of
the components, the hardware
test generates an error message for you. Macintosh computers will display
a text message, for example, or an icon if it’s bad enough (see Figure 2.3). If
there are no hardware problems to report, then the last thing that the
hardware test does is locate and execute the files that start the operating
system.
Data Flow
You’ll see the ROM-BIOS
referred to as the System BIOS
or System ROM by many
computer people. All three
terms are acceptable.
Even this early in the boot process, the interplay between CPU, RAM, and
storage devices comes into play. ROM stores the little programs that support
the absolutely necessary, hard-wired into your computer devices: basic
Figure 2.3: Unhappy Mac icons
20
COMPUTER LITERACY: YOUR TICKET TO IC3 CERTIFICATION
input devices, such as
the keyboard, and
fundamental output
devices, such as the
tiny speaker inside
your case and the
monitor. These little
programs, called
services, load from the
very slow ROM into
the shockingly fast
RAM (Figure 2.4).
The CPU does
almost all the processing,
as you know from Chapter 1,
but RAM plays a fundamental
part in the computing process. The CPU uses RAM like you use shortterm memory. If you want to do a complex math problem (and who
doesn’t?!), for example, you would most likely need to use a book to look
up the formulas and then, with numbers in your head, you could process
the problem. If you didn’t have short-term memory, you couldn’t keep the
necessary information in your head long enough to do the job, right? The
CPU and RAM have that same relationship. The RAM holds every bit of
data the CPU processes.
Figure 2.4: The flow of data from
ROM to RAM
Operating System Load
The operating system takes over the boot process from here, instructing
the CPU to copy all of the necessary system files, services, drivers, and
IBM-style PCs refer to the
hardware test phase as the
Power On Self Test (POST).
Macintosh computers use the
more generic term.
Figure 2.5: Logon dialog in Windows
CHAPTER 2: GOING WITH THE DATA FLOW
21
Figure 2.6: The boot process
other files that make up the operating system from the hard drive to the
computer’s RAM. As a final step, the operating system builds the user
interface (using the video display adapter to draw the interface on your
monitor), and soon you see the logon dialog or the icons next to user names
(Figure 2.5). Figure 2.6 illustrates the boot process.
The data keeps flowing
Figure 2.7: The flow of data from
hard drive to RAM
The operating system files travel from a mass storage device,
such as a hard drive, CD-ROM disc, or, in the ancient days, a
floppy disk, through the motherboard into RAM (Figure 2.7).
You saw this process with the tiny services programs,
flowing from ROM to RAM. The process repeats here.
I’ll let you in on a little secret. The flow of data
follows the same process in almost every aspect of
the computer! You’ll see this pattern
again and again.
Assuming there are no hardware
problems, the whole process only takes
a few seconds, and you’re ready to log
on and start your computing session.
Keep in mind that except for the
previously-mentioned blinking
lights, beeps (and any optional
sound files, such as the soothing
Windows Logon Sound audio
file), and the sound of the disk
drives spinning up to speed,
there’s really not much to see.
All of the action happens inside the CPU, RAM, and storage devices.
Phase Two: The Dance
– Interacting with the Computer
Inside every computer is a
small crystal called the clock
or System Clock that sets the
timing for all the other hardware .
22
Once you’ve booted up, you’re ready for the next phase, interacting with
the computer. You can open a program—such as a word processing program
to type a letter to your mother or write an essay from the essay questions
at the end of the chapter. (Something you’re looking forward to doing,
right?!) The computer processes your request, opening the application
interface so you can type something in. The computer processes what you
type and updates the screen to give you feedback. Rinse and repeat this
COMPUTER LITERACY: YOUR TICKET TO IC3 CERTIFICATION
cycle many times quickly and you’ve got the
whole’“interaction” part of the computing process.
To make this interaction possible, you have to use input
devices; the computer uses internal devices to process, then
uses output devices to show your work. Let’s look at all
three components of the interaction phase, including
practical steps on opening applications and creating data.
Input Devices
Input devices enable you to give commands to the
computer. You can type using the keyboard; click on
icons and buttons using a pointing device such as a
mouse, trackball, or touchpad; or speak using the
microphone (Figure 2.8). More specialized input
devices, such as joysticks and game pads, enable you
to fly a simulated
airplane more naturally
than using a keyboard,
for example, or enhance
your game play in firstperson games (Figure
2.9). Some multimedia
computers even use
remote controls, just like
the kind used for
televisions.
Some specialized
input devices also enable
you to add data to the
computer. You
Figure 2.9: Using a joystick in
Microsoft’s Crimson Skies game
can take a picture of your cat
with a digital camera, for example,
and then pull that picture into the
computer so you can share it
with friends, family, and random
people who drop by your house
(Figure 2.10). A digital video
camera enables you to create your
own movies, editing and
watching them directly on the
computer. A scanner enables you
Figure 2.8: Standard
input devices
Other Specialized Input
Devices
Manufacturers have created an
amazing variety of devices for
inputting both commands and
data. We created most of the
artwork you see in this book, for
example, using a drawing tablet
(also called a digitizing tablet)
and pen, rather than mouse and
keyboard (see Figure 2.11).
Barcode readers that you see at
every supermarket take data—
information about your food
item—and bring it into the cash
register (which is just another
computer!). The scientific and
medical communities use special,
computer-based probes and
instruments for cutting edge
research and life-saving procedures. Alternative input devices,
such as thumb mice and radically
innovative keyboards, enable
physically-challenged users to
work with computers as readily
as everyone else. Figure 2.12
shows a side-folded keyboard.
Figure 2.10: Importing image from digital camera to computer
CHAPTER 2: GOING WITH THE DATA FLOW
23
Figure 2.11: Graphics tablet and pen
Figure 2.13: Typical scanner
Installing Input Devices
All this talk about input devices
might have sparked your
curiosity. (Even if it hasn’t, humor
me here!) What sort of input
devices do you have handy? Do
an informal survey of teachers,
family, and friends to find out
what they use to input data or
commands into any media, not
just computers. Get creative here
and write them all down. Here’s a
hint: what input device will you
use to write your list?
Figure 2.12: Side-folded keyboard
to create a digital image of an old-fashioned photograph, (just in case you’ve
gone retro and started using a Polaroid). You can also use a scanner to
import a type-written document directly into a word processing program,
which is pretty cool when it works, a process called optical character
recognition (OCR). Figure 2.13 shows a typical scanner.
Finally, a whole host of devices
enable you to input commands and
data in the most basic way possible:
poking them with your fingers.
Every personal digital assistant
(PDA), information kiosks,
and automated teller
machines that give out free
money have touch screens
that react to contact with
your fingers or specialized
stick (Figure 2.14).
Figure 2.14: PDA in use
Installing Input Devices
Most operating systems support some input devices—especially keyboards
and mice—straight out of the box, but others require a two step installation
process. First, you plug the device into its proper spot. Second, you load a
disc in your CD player and install a bit of support software so the OS knows
what sort of device it now has.
Physical Connections
Some devices require that you
reverse this process; that is,
install the software before you
plug in the hardware. Read the
documentation that comes
with any new device before
you plug it in!
24
Devices connect to the computer’s hardware through connector ports,
usually located on the back of your computer case, although you’ll find
some universal connectors on the front or side of the case for quicker access.
Portable computers typically have ports located on the back, sides, front—
pretty much anywhere that the makers can fit them to give you the most
access. Figure 2.15 shows the back side of a desktop computer.
Ports come in several varieties, as you can see, but with one exception,
you can’t go wrong when you plug in devices. Manufacturers key ports
and connectors by giving them odd shapes, thus making it impossible to
plug them in incorrectly. Traditional keyboards and pointing devices (such
COMPUTER LITERACY: YOUR TICKET TO IC3 CERTIFICATION
It doesn’t hurt anything to plug
the keyboard into the mouse
port or the mouse into the
keyboard port. They simply
won’t work. If you do this
accidentally, just turn off the
computer, swap them out, and
hope no one was looking!
Figure 2.15: Input ports
as mice) plug into the small round connectors labeled on the left (in Figure
2.15), and provide the exception to this rule. You can easily plug a keyboard
into the mouse port, and vice versa, but your devices won’t work. Most PC
makers color-code the mouse and keyboard connectors to keep you from
getting confused: green for the mouse and purple for the keyboard.
Most input devices today plug into one of the two universal ports,
universal serial bus (USB) or FireWire, although you’ll see some devices
plugged into legacy ports, such as the MIDI port shown in Figure 2.16.
These ports are keyed and labeled with their own icons. You can’t mess up
here.
Warning: You can plug USB
and FireWire devices in with
the computer running and the
computer will automatically
recognize them. Do not do this
with keyboards or mice,
because you take the chance
of burning out the ports. MIDI
ports offer nothing either
way—the computer won’t
recognize the device automatically, but you’ll do no harm.
Software Support
Input devices usually require some software support programs installed
so the operating system can communicate with them effectively. Although
USB and FireWire tout the ability to plug and play devices—meaning you
just plug them in, the OS recognizes them, and you can use them—this
rarely works in the real world. The OS often recognizes the hardware, but
doesn’t know how to talk to it! Hardware manufacturers provide a CD
with small programs, called drivers, that the OS copies and loads into RAM
to support the input device.
Internal Processing
Now that you have input devices sorted out, it’s time to get to work. You
need to command the computer to open an application and the CPU
MIDI stands for musical
instrument digital interface,
and indeed provided a way to
connect electronic musical
equipment to the computer,
back in the day. Modern MIDIenabled instruments connect
through USB or FireWire ports,
just like everything else.
Figure 2.16: MIDI port for legacy joysticks and other ancient devices
CHAPTER 2: GOING WITH THE DATA FLOW
25
Figure 2.17:
Selecting a
program to open
Figure 2.18: The flow of data
when opening an application
processes that command. The CPU does not
work solo, though, requiring numerous
other components to do both the
processing and the next step, providing
output of some sort.
Opening Programs
You can start an application in many ways, but the most common way in
graphical-based OSs such as Windows and Macintosh OS X is to click the
program icon in the Start menu (Windows) or double-click the program
icon in the Finder (OS X). See Figure 2.17. Clicking and double-clicking,
usually accomplished by a pointing device, tells the computer that you
want it to run a specific program installed on the computer.
Al Gore or Something
Like That
A computer uses algorithms (a
set of pre-designed rules) to
handle the data appropriately.
For example, if you open up a
Calculator application and use
your keyboard to type 1+1, your
computer will use an addition
algorithm to sum the data.
26
Many Ways to Open
Almost every OS offers you many ways to start a program. You can double-click the
program’s icon on your desktop in Windows, for example, or click the Start button, select
Run from the menu, and then browse to the location of the program’s executable file (the
file that starts the program.)
You can also double-click a data file associated with the program, meaning the OS
knows to load a specific application when you select a specific file type. Selecting a text
document (like a letter), for example, will start your text editor (such as Microsoft Word)
open with that document ready to edit; choosing a music file (such as a song saved as an
MP3) will launch your default media player (such as Windows Media Player or iTunes) and
begin playing the song. This process is called file association.
COMPUTER LITERACY: YOUR TICKET TO IC3 CERTIFICATION
Figure 2.19: Data flow from
CPU to video to monitor
The operating system and the CPU interpret your
command and send commands to the hard drive to cough
up the files for that application so they can be loaded into
RAM. This process sounds familiar, right? To work with
any application, the CPU must have that application loaded
into RAM. Figure 2.18 illustrates the flow of data from hard
drive to RAM so the CPU can work.
What you see as a result of this processing requires more
internal components. To change the display so you get the
application interface, for example, the CPU has to send data
and commands to the video card inside your system. The
video card then processes the CPU’s commands and sends
commands to the monitor so the monitor updates. All of
this happens very quickly, but you see the change on the
screen. Figure 2.19 illustrates this process.
Creating Data Files
Once you have an application open, you can
create new files. Almost every productivity
application—as opposed to games—has a File
option on the main menu. Creating a file is as
simple as going to File | New and then
specifying what sort of file you want. Microsoft
Word opens a separate dialog called the Task Pane to give
you a bunch of choices (see Figure 2.20).
Output Devices
To engage fully in the
“interacting with the computer”
phase, you need properly
connected and configured output
devices. Output takes many
forms, though, from standard feedback
options of changing the display and making
sound come out the speakers, to more
specialized feedback such as force-feedback
joysticks shaking your arm when you take a
dive in your jet fighter. Other forms of output
include printing, communicating over a
network (like the Internet), and saving files
to some sort of mass storage, such as a hard
drive or compact disc.
Feedback Devices
Figure 2.20: Task Pane
in Microsoft Word
The monitor provides the most common way
for the computer to communicate with you,
showing that it has processed your commands
by loading a program, changing some file, or
simply moving the mouse pointer across the
screen to match your hand movement. Figure
2.21 shows a pair of monitors.
Creating
You’ve read about it and
probably listened to your
instructor tell you about it;
wouldn’t it be more fun if you
just did it? So, what are you
waiting for? If you have a
Windows computer to work on,
click the Start button and go to
All Programs. What do you
have installed on the computer?
What about under the Accessories folder? Open up a couple of
programs, such as Solitaire and
WordPad. Use the latter to
create a new document. What
sort of feedback do you get
from the computer when you
work in these applications?
CHAPTER 2: GOING WITH THE DATA FLOW
27
Figure 2.21: LCD vs.
CRT: Fight!
Types of Monitors
Monitors come in two varieties,
cathode ray tube (CRT) and
liquid crystal display (LCD).
CRTs use the same technology
as most televisions and are
large, heavy, and power-hungry.
LCDs take up less desktop
space, are lighter, and use less
power than CRTs.
Projectors offer a nice alternative to monitors,
enabling you to put the computer image on a
screen or white wall, rather than only on a
smaller physical display (Figure 2.22). If the bulbs
weren’t so expensive and energy-hungry, you’d
undoubtedly see projectors replacing televisions
as well as computer
Figure 2.22:
monitors!
Projector
Speakers
give the
computer
another way to
provide feedback (and
playback, for that matter).
Operating systems and applications
can send sounds out when things go
wrong or to acknowledge that they
accomplished what you commanded.
Media applications, like iTunes, can play
music when requested. Good speakers can
make a huge difference in games and in movie
watching on the computer. Figure 2.23 shows a
set of decent speakers.
Figure 2.23: Speakers
Voice synthesizers enable visually challenged folks to participate fully
in the computer revolution, creating essential feedback from the computer
that they otherwise wouldn’t receive. Many developers have software voice
synthesizers that use your computers sound processor and speakers, but
some manufacturers have external hardware devices that do the trick. For
the latter, check out the good folks at www.freedomscientific.com.
Hardcopy
Despite the promise of the so-called “paperless office” that the computer
age was supposed to usher in, most folks prefer to see their work printed
out on good old-fashioned, tree-killing, finger-cutting paper. Modern
printers enable you to turn your PC into a print shop and produce attractive
28
COMPUTER LITERACY: YOUR TICKET TO IC3 CERTIFICATION
text documents like reports and newsletters, as well as photos,
banners, postcards, and other graphical documents (Figure 2.24).
Networking
Network output means sending data to another computer by means
of networking hardware and software. To make it work, you’ve got
to have a computer connected to a network or dialed in via a hardware
device called a modem. Part 3 of this book covers networking in great
detail, so we’ll leave that discussion for later.
Storage Devices
Opening a data file from within your application program causes the
computer to copy the file from your storage media into the system’s RAM
(Figure 2.25). This is your editable, “working” copy of the file. You’re free
to make changes by adding text, entering numbers, slaying dragons, or
doing whatever the application program does.
Figure 2.24: Printer
Plotters
Figure 2.25: File stored and in use
As you’ll recall from earlier in the chapter, the CPU can work with files
and programs held in RAM, its short-term memory. As you interact with
the computer, the CPU updates the contents of RAM according to what
you do, and that’s great. You can work on drawing a masterpiece, for
example, and what you see on your monitor also appears (in a slightly
altered format) in RAM. There’s just one problem.
If RAM loses power, all the data it holds just goes away. Poof. Gone forever.
That’s why it’s important to save your work. Saving a data file copies it
from RAM onto a mass storage device, such as a hard disk, where it’s
retained permanently (Figure 2.26).
All applications give you methods for saving a file, such as clicking a
Save button, going to File | Save, or pressing [Ctrl + S] (for Windows) or
[Cmd + S] (for Macintosh) on the keyboard. Figure 2.27 shows the saving
dialog in Word.
People have used different types of media for data storage through the
years, from stone tablets to magnetic reel-to-reel tapes. Three technologies
dominate the current storage scene for computers: magnetic, optical, and
solid state.
Hard drives, floppy disks, and Zip disks save information magnetically
on platters. Hard drives provide the primary fixed mass storage in almost
If you need to print something
huge, like poster sized, you need
to walk away from the typical
home and office print device and
embrace the goodness of the
plotter. Plotters look like scaledup printers and run anywhere
from $2000 to $20,000 and up
(in U.S. dollars), but they’ll print
your big pictures just fine.
Plotters produce large-scale,
detailed printouts, such as
architectural drawings, blueprints, maps, and posters.
Keep an Eye on Your
Applications with Task
Manager
The Windows Task Manager
utility lets you view the programs
and processes that are currently
stored in memory and running
on your computer. Press the
[Ctrl] + [Alt] + [Delete] key
combination once to bring up the
Windows Security dialog box,
and then click on the button
labeled Task Manager. Running
programs are listed on the tab
labeled Applications.
CHAPTER 2: GOING WITH THE DATA FLOW
29
Figure 2.26: File being copied from
RAM to hard drive
Random Memories
The name Random Access
Memory is a bit misleading.
There’s nothing random about
the way that RAM stores
data.’“Random” simply means
that any part of memory’s
storage area can be read as
easily as any other part. It
doesn’t have to be in sequence.
every computer. Figure
2.29 shows a hard drive
open to reveal the platters
inside.
CD- and DVD-media
drives use optical lasers to
read information stored on
shiny discs, like the AOL
discs found on every street
corner. These optical drives
provide the most common
form of removable mass
storage on computers.
Figure 2.29 shows an
optical drive.
Figure 2.27: Saving in Word
Acronym Soup
CD- and DVD-media drives and discs use different designations, such as CD-ROM, CD-R, CD-RW, DVD-ROM, and DVD+RW. The
initials stand for variations of the same optical technology, offering different storage capacity (DVDs can store many times more data
than CDs) and the ability to write or rewrite data on the same disc.
•
CD-ROM and DVD-ROM are read-only memory formats. The data that’s stored on CD-ROM and DVD-ROM discs can’t be
changed.
•
CD-R and DVD-R stand for recordable. These types of optical media can be recorded onto, or burned, if you’ve got the appropriate type of CD or DVD optical drive. This kind of optical media can only be recorded once, however.
•
CD-RW, DVD-RW, and DVD+RW stand for rewritable. These types of optical media can be recorded and re-recorded onto
numerous times.
Because the different types of CD/DVD drives follow the same standards, disks recorded on one type of device should be readable
by another type of device. That is, a disk burned on a CD-RW drive should be readable on any CD-ROM and CD-R drive. Older CDbased media drives can’t read DVDs, but DVD drives have no trouble reading CD media. Many modern drive devices are combination
drives, meaning that they can read and write to any type of CD or DVD media.
30
COMPUTER LITERACY: YOUR TICKET TO IC3 CERTIFICATION
Figure 2.29: CD-RW
drive and disc
Figure 2.28: Hard drive
Figure 2.30: Flash memory devices
The solid state flash memory offers a
lot of storage in a small container, plus
it’ll retain information without
electricity. Manufacturers package
flash memory in a number of
different formats, such as
removable USB thumb drives;
postage-stamp-sized
SmartMedia, Secure Digital
(SD), and Compact Flash
cards; and Memory Stick cards that are roughly the size of a stick of gum
(Figure 2.30). Portable electronics like MP3 music players, digital cameras,
cell phones, and PDAs, as well as PCs, use Flash memory cards.
Connecting Output Devices
Like with input devices, operating systems support some output devices
straight out of the box, but others require a two step installation process.
First, you plug the device into its proper spot. Second, you load a disc in
your CD player and install a bit of support software so the OS knows what
sort of device it now has (or vice versa—software then installation).
Physical
Connections
Output devices
connect to the
PC’s hardware
t h r o u g h
connector ports
on the case and
Remote Storage
In today’s networked world, mass
storage doesn’t necessarily have
to be physically attached to a
particular computer. One of the
biggest benefits to networking is
the ability to share mass storage
devices on remote computers on
your LAN, or on servers located
“out there” on the Internet
somewhere. This is collectively
called remote storage, or
sometimes virtual storage.
Figure 2.31:
Output ports
CHAPTER 2: GOING WITH THE DATA FLOW
31
Some smaller devices, such
as PDAs, can network wirelessly using infrared light. These
devices use appropriately named
nfrared ports to connect.
Legacy Connector Ports
It seems like newer and better is
the order of things in the
computer world. Nonetheless,
some older technologies persist
long after you’d think they’d
disappear. These kinds of
technologies are called legacy
technologies. Legacy technologies are retained on newer
computers for one reason: so that
older hardware will still work on
them. Techs call this backwards
compatibility.
Two examples of legacy
technology are the serial and
parallel ports. Hardware that may
connect to serial ports includes
external modems and specialized
print devices such as label
printers. Devices that use the
parallel port include external
storage devices and scanners.
The most common use for this
connector, however, is for printers.
In fact, many folks call the parallel
port the “printer port,” which isn’t
entirely correct, but it’s not worth
arguing about, either.
through data cables inside the case.
Figure 2.31 shows the back
side of a desktop computer.
Your monitor connects
to one of the video ports,
either the traditional 15pin VGA port or the
newer DVI port (see
Figure 2.32:
Figure 2.31). Both
External FireWire
types of connectors are keyed, so
hard drive
you can only plug them in correctly.
Audio ports on most computers are the common, mini-audio sockets
seen on most small consumer audio devices. Computers typically have
three color-coded audio ports: a green speaker output port, a pink
microphone input port, and a blue auxiliary input port.
Networks are collections of computers that interconnect and share data
and other resources. You connect your computer to networks through two
different devices, a modem and a network adapter. The connectors for these
devices are called RJ-11 and RJ-45 connectors, respectively, and you’ll hear
their ports referred to as telephone ports and Ethernet or network ports.
Almost every other output device connects to one of the universal ports
you saw earlier in this chapter, USB and FireWire. FireWire seems limited
to higher-end printers and external hard drives, whereas you can get almost
any device in USB. Figure 2.32 shows a hard drive with a FireWire
connection.
Internal drives connect to the motherboard via ribbon cables, usually
flat 34-wire, 40-wire, and 80-wire gray affairs. Modern hard drives use a
smaller, 8-wire cable. Figure 2.33 shows a motherboard with a hard drive
and CD-media drive connected.
Figure 2.33: Motherboard out
of the case with hard
drive and CD-media
drive connected
Software
Support
Output devices
aside from the
monitor require some
software support programs
installed so the operating system can
communicate with them effectively.
Hardware manufacturers provide a CD
with drivers that the OS copies and loads into
RAM to support the output device.
You should leave installing and
uninstalling mass storage
devices to trained, CompTIA
A+ certified technicians.
32
COMPUTER LITERACY: YOUR TICKET TO IC3 CERTIFICATION
Phase Three: Park It – Properly Closing Programs
and Shutting Down the Computer
When you’re driving from one location to another, upon arrival, do you
simply step out of the car and leave it running? Of course not! You roll up
the windows, shut off the engine, and lock the doors. If you’ve brought
things with you, like a backpack, wallet, or cell phone, you take those things
when you leave the car.
Well, it’s the same idea with your computer. Do you simply walk away
when you’re done with your work? Not if you’re smart! There’s a proper
order to making sure that your work is saved and your computer secured
before you walk away from your desk. This is most important in an
environment where you share the computer with other users.
You should close things down properly for three reasons: avoiding
corruption of your applications or operating system, personal security, and
doing your part to save the planet. Sounds like quite a stretch for simply
shutting down a computer, but let’s take a look.
Anti-Corruption
One of the first things that you should learn as a computer user is that you
should never turn off the computer while the operating system or
applications are running. This is true for Windows, OS X, and all versions
of Linux, (although not true for PDAs running PalmOS or PocketPC). The
reason for this is simple: to prevent data loss. Data, application, and OS
files held in RAM are in a vulnerable state. If you mistakenly click the
wrong button, or if your computer loses power, then the data may be
flushed out of RAM without saving it to disk. In the case of data files, this
means any work that wasn’t saved is gone. With program and OS files,
this can mean file corruption that may prevent them from running properly
the next time you fire them up.
Shutting down properly involves three or four steps. First, save and
close any data file you’re working on. We looked at this process earlier in
the chapter. Second, close any running applications. You can do this in
quite a few ways, such as clicking the Close button. In Windows programs,
it’s the little X button located in the top right-hand corner of the application
window, as you can see in Figure 2.34. You can also go to File | Exit on the
main menu. Most applications respond to a hotkey combination, such as
[Alt + F4] in Windows or [Apple + Q] in OS X.
The third and fourth steps involve logging out of the operating system
and powering down the computer. Doing these steps properly avoids file
corruption, but also provide
other benefits, such as
security and energy
savings.
Figure 2.35: Letter
supposedly from “Mom”
Unlike with input devices, you
run no risk plugging external
output devices in while the
computer is running.
Playing with Plugs
You’ve read about external
output devices, so now it’s time
to play with them. What’s
plugged into your computer?
Try unscrewing and unplugging
the monitor cable from the video
port. (Trace the connection from
the back of the monitor.) What
kind of video do you have?
What was the effect of unplugging the video cable when the
computer was running? Try
plugging it in only part way.
What does that do to your
screen? What other output
devices do you have?
Figure 2.34: Close button
What’s the Worst that
Can Happen?
Information stored in RAM while
you’re using an application
includes not only your data files
and application program files, but
also your essential OS files. In
some cases, incorrectly shutting
down the computer will damage
the OS itself!
CHAPTER 2: GOING WITH THE DATA FLOW
33
Personal Security
Fast User Switching
By default, Windows XP Home
allows you to log off without
closing your applications, using
what’s called Fast User Switching. You can do this semi-log off
by pressing the [Windows key +
L] keyboard combination.
Have you ever received a letter from someone? How did you know the
person who wrote it is the person you think wrote it? Handwriting
recognition might help, but what if the letter is typed? What would you do
if you received the letter in Figure 2.35. Seems like a pretty exciting
opportunity, right?
Mom never wrote that letter. It’s a scam; but if the letter had your mom’s
address as the return address and the postage information seemed correct,
you might have second thoughts. In the world of computers, the potential
for such identity theft cranks up to very high.
If you walk away from your computer, still logged in, the next person
who sits down at that computer can become you as far as the rest of the
world can tell. The thief could use your computer to hurt others, to steal,
to do all sorts of mischief, all while appearing to be you. Guess who will
take the heat for the evil deeds? You will.
When you walk away, you need to log out. To log out in Windows, go
to Start | Log Off or press [Ctrl + Alt + Delete] once and click the Log Off
button in the Windows Security dialog box. To log out in OS X, go to the
Apple menu and select Log Off. Couldn’t be simpler!
Green Acres
Computers use electricity, some at a huge rate, and unfortunately for
computer users, electricity doesn’t grow on trees. As computers go into
service in every aspect of life, the demand for electricity goes way up. The
fourth step in the proper shut down process, therefore, is to close the
operating system and power off the computer. This generally takes a single
action on your part. In Windows, for example, rather than simply logging
out, you can go to Start | Shut Down to log out, close the OS, and power
down.
Because it takes more electricity to power up a computer than to leave
one sitting idle, you should follow this basic rule with your computer use.
Power up when you want to use the computer and then power down at
the end of the day or when you’re done using it for the day.
34
COMPUTER LITERACY: YOUR TICKET TO IC3 CERTIFICATION
■ The flow of data starts with the boot process.
First you turn the power on, waking the CPU.
The CPU then communicates with the ROMBIOS memory chip to start the hardware test
process. The ROM-BIOS memory chip contains vital programs that enable your computer to identify its hardware and start itself
when you press the power button.
■ The operating system takes over, loading
from the hard drive into RAM and presenting the user with a user interface. You can
log in at that point.
Phase Two: The Dance – Interacting with the
Computer
■ Once booted, you can get to work by typing
a command or double-clicking an icon or
program file. The computer processes your
request, opening the application interface so
you can type something in. The computer
processes what you type and updates the
screen to give you feedback.
■ Input devices enable you to give commands
to the computer. You can type using the keyboard; click on icons and buttons using a
pointing device such as a mouse, trackball,
or touchpad; speak using the microphone; or
game with a joystick or game pad.
■ Some input devices also enable you to add
data to the computer. You can take a picture
of your cat with a digital camera, for example.
A scanner enables you to create a digital image of an old-fashioned photograph. You can
also use a scanner to import a type-written
document directly into a word processing
program, a process called optical character recognition (OCR).
■ Devices connect to the computer’s hardware
through connector ports, usually located on
the back of your computer case.
Manufacturers’key ports and connectors by
giving them odd shapes, thus making it impossible to plug them in incorrectly. Most
input devices today plug into one of the two
universal ports, universal serial bus (USB)
or FireWire.
■ Input devices usually require some software support programs installed so the
operating system can communicate with
them effectively. Hardware manufacturers
provide a CD with small programs, called
drivers, that the OS copies and loads into
RAM to support the input device.
■ You can use input devices to start an application. The most common way in
graphical-based OSs such as Windows and
Macintosh OS X is to click the program icon
in the Start Menu (Windows) or doubleclick the program icon in the Finder (OS
X). The operating system and the CPU interpret your command and send commands to the hard drive to get the files for
that application so they can be loaded into
RAM and the CPU can process them.
■ Once you have an application open, you
can create new files. Almost every productivity application—as opposed to games—
has a File option on the main menu. Creating a file is as simple as going to—File |
New and then specifying what sort of file
you want.
CHAPTER 2: SUMMARY
Phase One: Start Me Up! – The Computer’s
Boot Process
■ To engage fully in the “interacting with the
computer” phase, you need properly connected and configured output devices.
Output takes many forms, such as standard feedback options of changing the display and making sound come out the
speakers. Other forms of output include
printing, communicating over a network
(like the Internet), and saving files to some
sort of mass storage, such as a hard drive
or compact disc.
■ Three technologies dominate the current
storage scene for computers: magnetic,
optical, and solid state. Hard drives and
floppy disks save information magnetically on platters. Hard drives provide the
primary fixed mass storage in almost ev
CHAPTER 2: GOING WITH THE DATA FLOW
35
CHAPTER 2: SUMMARY
36
ery computer. CD- and DVD-media drives
use optical lasers to read information stored
on shiny discs. These optical drives provide
the most common form of removable mass
storage on computers. The solid state flash
memory offers a lot of storage in a small container, plus it’ll retain information without
electricity. Manufacturers package flash
memory in a number of different formats,
such as removable USB thumb drives and
postage-stamp-sized SmartMedia.
■ Output devices connect to the PC’s hardware
through connector ports on the case and
through data cables inside the case. Your
monitor connects to one of the video ports,
either the traditional 15-pin VGA port or the
newer DVI port. PCs typically have three
color-coded audio ports: a green speaker
output port, a pink microphone input port,
and a blue auxiliary input port. Almost every other external output device connects to
one of the universal ports, USB and FireWire.
Internal drives connect to the motherboard
via ribbon cables, usually flat 34-wire, 40-wire,
and 80-wire gray affairs. Modern hard drives
use a smaller, 8-wire cable.
COMPUTER LITERACY: YOUR TICKET TO IC3 CERTIFICATION
Phase Three: Park It – Properly Closing
Programs and Shutting Down the
Computer
■ You should never turn off the computer
while the operating system or applications are running. To do so runs the risk
of corrupting your application or operating system files.
■ Shutting down properly involves three
or four steps. First, save and close any
data file you’re working on. Second,
close any running applications, often by
going to File | Exit or File | Quit. The
third and fourth steps involve logging
out of the operating system and powering down the computer. In Windows, go
to Start | Log Off or Start | Shut Down;
in OS X, go to Apple menu | Shut
Down.
Algorithms
Plug and play
Boot
Power supply
Digital camera
Printer
Drivers
Projector
FireWire
Remote storage
Flash memory
Read-only memory-basic input/
Game pad
output system (ROM-BIOS)
Input devices
Ribbon cable
Joystick
Scanner
Key
Services
Keyboard
Solid-state storage
Magnetic storage
Speakers
Microphone
System clock
Monitor
Thumb mouse
Mouse
Touchpad
Musical instrument digital interface (MIDI)
Trackball
Optical character recognition (OCR)
Universal serial bus (USB)
Optical storage
Video card
Output devices
Voice synthesizer
Plotter
CHAPTER 2: GOING WITH THE DATA FLOW
CHAPTER 2: REVIEW
Key Terms
37
CHAPTER 2: REVIEW
38
Key Term Quiz
Use the Key Terms list to complete the following sentences. Not all the terms will be used.
6. Hard disk drives and floppy diskettes are
examples of __________________.
1. The _______________ converts alternatingcurrent (AC) electricity that comes out of
your wall socket into direct current (DC)
used by the computer.
7. John can use a __________________ to
give voice commands to his computer.
2. A ________________ makes a digital image
of a text document or photo, which you can
then edit on your computer.
3. The __________________ draws the images
that you see on your display monitor.
4. __________________ devices access data
stored on reflective disks using laser light.
5. External devices that need consistent, highspeed access to the computer, such as
storage drives and digital video
camcorders, connect to the computer using
__________________.
COMPUTER LITERACY: YOUR TICKET TO IC3 CERTIFICATION
8. _________________ uses the same storage
technology as RAM, but is non-volatile
(doesn’t need constant power to retain
data.)
9. A visually-impaired user could get
feedback from the computer with a
__________________, thus enabling him
or her to enjoy interacting with the
computer.
10. A __________________ is a type of printer
used to produce large, detailed drawings
such as blueprints.
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