Chapter 4

T e a c h e r s D i s c o v e r i n g C o m p u t e r s

Integrating Technologyin the Classroom3rd Edition

Chapter 4

Hardware for Educators

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CHAPTER 4 OBJECTIVESCHAPTER 4 OBJECTIVES

Describe the system unit Define the term bit, and describe how a

series of bits are used to represent data Identify the major components of the

system unit and explain their functions Explain how the CPU uses the four steps

of a machine cycle to process data List the characteristics of a keyboard and

identify various types of keyboards

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Identify various types of pointing devices

Differentiate among the four types of output

Identify the different types of output devices

Explain the differences among various types of printers

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Differentiate between storage and memory

Identify types of storage media and devices

Explain how data is stored on floppy disks, hard disks, and CD-ROMs

Differentiate between CD-ROMs and DVD-ROMs

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THE SYSTEM UNITTHE SYSTEM UNIT

System unit• Box-like case that

houses the electronic components of the computer that are used to process data

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DATA REPRESENTATIONDATA REPRESENTATION

Analog vs. Digital Digital

• Two states– (1) on– (0) off

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Binary number system Combination of ones and zeroes

represent characters

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ASCII• American Standard Code for Information

Interchange• Converting a keyboard stroke into a byte

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THE COMPONENTS OF THE SYSTEM UNITTHE COMPONENTS OF THE SYSTEM UNIT

The Motherboard• Contains many of the electronic

components• Chip

– A small piece of semiconducting material on which one or more integrated circuits are etched

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THE COMPONENTS OF THE SYSTEM UNITTHE COMPONENTS OF THE SYSTEM UNIT

CPU and Microprocessor• Interprets and carries out the basic

instructions that operate a computer• Microprocessor contains the CPU in a PC

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CPU AND MICROPROCESSORCPU AND MICROPROCESSOR

The Control Unit• A component of the CPU that directs and

coordinates most of the operations in the computer– Fetch – get the next instruction from memory– Decode – translate the instruction– Execute – carry out the command– Store the result – write the result to memory– Machine cycle

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The Arithmetic/Logic Unit• Performs the execution part of the machine

cycle• Arithmetic (addition, subtraction,

multiplication, division)• Comparison (greater than, equal to, less

than)• Logical (AND, OR, NOT)

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The System Clock• Synchronizes all computer operations• Each tick is called a clock cycle• Faster clock means more instructions the

CPU can execute each second• Speed measured in megahertz (MHz)

– One million ticks of the system clock

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Memory• Used to store data, instructions, and

information– The operating system and other system

software– Application programs– Data being processed by application programs

• Bytes are stored at specific locations or addresses

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Seats in a stadium are similar to addresses in memory:

(1) A seat in memory holds one person at a time, and an address in memory holds a single byte

(2) Both a seat and an address can be empty

(3) A seat has a unique identifying number and so does an address

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Memory• Size of memory is measured by the number

of bytes available

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CPU AND MICROPROCESSOR

Memory• Volatile memory – contents are lost when

the computer is powered down• Nonvolatile memory – contents are not lost

when the computer is powered down

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Random Access Memory (RAM)• The memory chips in the system unit• When the computer starts, operating

system files are loaded from a hard disk into RAM

• Synchronous Dynamic RAM (SDRAM)• Dual Inline Memory Module (DIMM)

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Random Access Memory (RAM)• RAM Chips

– Smaller in size than processor chips

– Packaged on circuit boards called single inline memory modules (SIMMs) or dual inline memory modules (DIMMs)

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Random Access Memory (RAM)• Configuring RAM

– The more RAM, the more programs and files a computer can work on at once

– Software usually tells you how much RAM is required

– Necessary RAM depends on what type of work the computer is used for

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Read-Only Memory (ROM)• Cannot be modified• Contents not lost when the computer

is turned off

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Expansion Slots and Expansion Cards• Expansion slot

– An opening, or socket, where a circuit board can be inserted into the motherboard

– Add new devices or capabilities to the computer

• Expansion card– Circuit boards, such as a modem or graphics

card, that add new capabilities to the computer

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Expansion Slots and Expansion Cards • Three common types

– Video card– Sound card– Internal modem

• PC Cards• Plug and Play

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Ports and Connectors• Port

– Point of attachment to the system unit– Usually on the back of the computer

• Connectors– Used to plug into ports

– Male connectors– Female connectors

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CPU AND MICROPROCESSOR

Ports and Connectors• New ports

– USB– USB 2.0– 1394 (FireWire)

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WHAT IS INPUT?WHAT IS INPUT?

Any data or instructions you enter into the memory of a computer• Data – unorganized facts• Program – series of instructions that tells

the computer how to perform a task• Command – an instruction given to a

computer program• User response – responses to questions or

messages from the software

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WHAT ARE INPUT DEVICES?WHAT ARE INPUT DEVICES?

Any hardware component that allows you to enter data, programs, commands, and user responses into a computer

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The Keyboard• Primary input device• Typing area• Numeric keypad• Toggle keys• Status lights• Arrow keys – arrow control keys• Function keys• Specialized buttons• Wireless keyboards

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Pointing Devices• An input device that allows you to control a

pointer on the screen– Block arrow– I-beam– Pointing hand

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Pointing Devices• Mouse

– One or two button mouse– Moving the mouse pointer– Clicking– Dragging– Double-clicking– Optical mouse– Cordless mouse

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WHAT ARE INPUT DEVICES?

Touchpad and Pointing Stick• Touchpad – small, flat, rectangular pointing

device that is sensitive to pressure and motion

• Pointing Stick – pressure-sensitive pointing device shaped like a pencil eraser

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Pointing Devices• Trackball

– Like a mouse, but the ball is on top

– Often used on portable computers

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Pointing Devices• Joystick

– Uses the movement of a vertical lever

– Often used with games

• Wheel– Steering-wheel type

input device– Used to simulate

driving a car

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Pointing Devices• Touch screen

– Monitor has a touch sensitive panel

– Used to issue simple commands or choose from a list of options

– Kiosks

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Optical Readers• Uses light to read characters, marks,

and codes and then converts them into digital data that can be processed by a computer

• Optical character recognition (OCR)– Reads character printed in OCR font

• Optical mark recognition (OMR)• Bar code


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Optical Scanner• Electronically

captures an entire page of text or images

• Converts text or image into digital data than can be stored and used

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Digital Cameras• Allows you to take

pictures and store the photographed images digitally

• Download, or transfer, pictures to your computer

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Audio and Video Input• Audio input

– Entering music, speech, or sound effects– Sound card– Speech Recognition

– Computer’s capability of distinguishing spoken words

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Audio and Video Input• Video input

– Entering a full-motion recording into a computer and storing the video on a hard disk or some other medium

– Video capture card


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WHAT ARE INPUT DEVICES?

Input Devices for Handheld Computers• Stylus• Voice Input• Portable keyboard• On screen keyboard

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Input Devices for Students with Special Needs• Americans with Disabilities Act (ADA)• Keyguard• Touch window• Pointing devices


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WHAT IS OUTPUT?WHAT IS OUTPUT?

Data that has been processed into information

Text Graphics Audio Video

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WHAT ARE OUTPUT DEVICES?WHAT ARE OUTPUT DEVICES?

Any computer component capable of conveying information to the user

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Monitors and Display Devices• Screen housed in a plastic or metal

case• Variety of sizes• Cathode ray tube (CRT)• Pixels• LCD (liquid crystal display) monitors

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WHAT ARE OUTPUT DEVICES?

Large Display Monitors• Allow an audience or

a group of students in a classroom to easily view images and multimedia displayed on a computer

• Available from 27 to 36 inches

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Large Display Monitors• High-definition

television (HDTV)• Gas plasma monitor

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Flat Panel Monitors and Displays• Uses liquid crystal

instead of a CRT• Consume less than

1/3 the power of a CRT

• Thinner and lighter than a CRT

• E-books

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WHAT ARE OUTPUT DEVICES?WHAT ARE OUTPUT DEVICES? Monitor Quality

• Resolution (sharpness and clarity)– Expressed as number of columns and rows

– 640 x 480

– 800 x 600

– 1024 x 768

• Dot pitch• Refresh rate• ENERGY STAR

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Printers• An output device that produces text and

graphics on a physical medium such as paper or transparency film

• Hard copy (printout)• Portrait vs. landscape• Printing requirements vary

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Impact Printers• Printing mechanism

strikes ink ribbon forming character on paper

• Not usually high quality• Dot-matrix printers• Continuous-form paper

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Nonimpact Printers• Do not strike paper• Much quieter• Ink-jet printers

– Spray tiny drops of ink onto the paper

– Both black-and-white and color

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Nonimpact Printers• Laser printers

– High-speed, high-quality nonimpact printer

– Very high quality resolution – 300dpi to 1,200 dpi

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Data Projectors• Allows an audience

to view output• LCD projectors• Digital light

processing (DLP) projector

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Facsimile (Fax) Machine• Used to transmit and

receive an image of a document over a phone line

• Stand-alone• Fax modem

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Multifunction Devices• Can print, scan, copy

and fax• Less space• Lower cost than

separate units

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Audio Output• Produce music,

speech, or other sounds

• Speakers• Headsets

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Output Devices for Students with Special Needs• Display instead of

sound for hearing impaired

• Change color and magnification on screen

• Braille printer

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WHAT IS STORAGE?WHAT IS STORAGE?

The media on which data, instructions, and information are kept

The devices that record and retrieve data, instructions, and information

Like a filing cabinet

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Storage Media and Devices• Storage medium

– Also called secondary storage– Physical material

• Storage device– Mechanism used to record and retrieve– Capacity measured in megabytes or gigabytes

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Floppy Disks• Portable, inexpensive

storage medium consisting of a thin, circular, flexible film enclosed in a square- shaped plastic shell

• Several sizes– 8-inch– 5.25-inch– 3.5-inch

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Characteristics of a Floppy Disk• Uses magnetic patterns to store data• Formatting

– Track– Sector

• Write-protection• Guidelines for floppy disk care• Floppy disk drive

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High-Capacity Removable Disks• Capacities greater

than 100 MB• Many uses

– Graphics, audio, or video

– Transporting files– Backups

• Zip drive

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Hard Disks• Provide large storage capacity and high

speed data access• Sizes range from 30 GB to 100 GB• Consists of several inflexible, circular disks,

called platters• Magnetic storage device• Formatting

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WHAT IS STORAGEWHAT IS STORAGE

External and Removable Hard Disks• External Hard Disk – Separate hard disk

that connects to a USB or FireWire port by cable– USB Drives

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CDs and DVDs• Optical storage media• Used to distribute software• Laser reads pits on the surface• Used on multimedia computers• Several types

– CD-ROM– DVD-ROM

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Care of CDs and DVDs• Can last from 5 to 100 years if properly

cared for• Never bend a disc• Avoid extreme temperatures and humidity• Keep away from contaminants• Do not stack or touch discs• Use a protective case

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CD-ROM• Compact disc read-

only memory• Can contain text,

graphics, video, as well as sound

• Can hold 650 MB of data

• Used for today’s complex software

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WHAT IS STORAGE?

CD-R and CD-RW• Compact disc-recordable

– Can write on each part of the disc only one time– Cannot be erased

• Compact disc-rewriteable– Can write on multiple times– Erasable disc

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DVD-ROM and DVD+RW• Digital video disc read-only memory (DVD-

ROM)– Can store from 4.7 GB to 17 GB– High quality– DVD-ROM drives– May replace CDs, VCRs, and VHS tapes

• Digital video disc+rewritable (DVD+RW)– Can write on multiple times– Erasable disc

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WHAT IS STORAGE?

Miniature Mobile Storage Media

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CHAPTER SUMMARYCHAPTER SUMMARY

Describe the system unit Define the term bit, and describe how a

series of bits are used to represent data Identify the major components of the

system unit and explain their functions Explain how the CPU uses the four steps

of a machine cycle to process data

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CHAPTER SUMMARYCHAPTER SUMMARY

Describe the four types of input and input devices

List the characteristics of a keyboard and identify various types of keyboards

Identify various types of pointing devices Differentiate among the four types of

output Identify the different types of output

devices

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CHAPTER SUMMARYCHAPTER SUMMARY Explain the differences among various

types of printers Differentiate between storage and

memory Identify types of storage media and

devices Explain how data is stored on floppy disks,

hard disks, and CD-ROMs Differentiate between CD-ROMs and DVD-

ROMs

T e a c h e r s D i s c o v e r i n g C o m p u t e r s

Integrating Technologyin the Classroom3rd Edition

Chapter 4 CompleteChapter 4 Complete

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Buyer’s Guide Buyer’s Guide 20042004

HOW TO PURCHASE, INSTALL, AND MAINTAIN A PERSONAL COMPUTER

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HOW TO PURCHASE A PERSONAL COMPUTER

Do you want a desktop or mobile computer?

For what purposes will you use this computer?

Should the computer be compatible with the computers at school or work?

Should the computer be a Mac or PC?

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HOW TO PURCHASE A DESKTOP COMPUTER

Determine the specific software you want to use on your computer

Look for bundled software Avoid buying the least powerful computer

available Consider upgrades to the mouse, keyboard,

monitor, printer, microphone, and speakers Determine whether you want to use telephone

lines or broadband (cable or DSL) to access the Internet

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If you are using a dial-up or wireless connection to connect to the Internet, then select an ISP or OSP

Use a worksheet to compare computers, services, and other considerations

If you are buying a new computer, you have several purchasing options: buying from your school bookstore, a local computer dealer, a local large retail store, or ordering by mail via telephone or the Web

If you are buying a used computer, stay with name brands such as Dell, Gateway, Hewlett-Packard, and Apple

If you have a computer and are upgrading to a new one, then consider selling or trading in the old one

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Be aware of hidden costs Consider more than just price Avoid restocking fees Consider purchasing an extended

warranty or service plan Use a credit card to purchase your new

computer

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HOW TO PURCHASE A NOTEBOOK COMPUTER

Purchase a notebook computer with a sufficiently large active-matrix screen

Experiment with different keyboards and pointing devices

Make sure the notebook computer you purchase has a CD and/or DVD drive

If necessary, upgrade the processor, memory, and disk storage at the time of purchase

The availability of built-in ports on a notebook computer is important

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If you plan to use your notebook computer for note-taking at school or in meetings, consider a notebook computer that converts to a Tablet PC

Consider purchasing a notebook computer with a built-in wireless card to connect to your home network

If you are going to use your notebook computer for long periods without access to an electrical outlet, purchase a second battery

Purchase a well-padded and well-designed carrying case

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If you travel overseas, obtain a set of electrical and telephone adapters

If you plan to connect your notebook computer to a video projector, make sure the notebook computer is compatible with the video projector

For improved security, consider a fingerprint scanner

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HOW TO PURCHASE A TABLET PC

Make sure the Tablet PC fits your mobile computing needs

Decide whether you want a convertible or pure Tablet PC

Be sure the weight and dimensions are conducive to portability

Port availability, battery life, and durability are even more important with a Tablet PC than they are with a notebook computer

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Experiment with different models of the Tablet PC to find the digital pen that works best for you

Check out the comfort level of handwriting in different positions

Make sure the LCD display device has a resolution high enough to take advantage of Microsoft’s ClearType technology

Test the built-in Tablet PC microphone and speakers

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Consider a Tablet PC with a built-in PC video camera

Review the docking capabilities of the Tablet PC

Wireless access to the Internet and your e-mail is essential with a Tablet PC

Review available accessories to purchase with your Tablet PC

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HOW TO PURCHASE A PDA

Determine the programs you plan to run on your PDA

Consider how much you want to pay Determine whether you need wireless

access to the Internet and e-mail or mobile telephone capabilities with your PDA

Make sure your PDA has enough memory

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Practice with the touch screen, handwriting recognition, and built-in keyboard before deciding on a model

Decide whether you want a color display Compare battery life Even with PDAs, seriously consider the

importance of ergonomics

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Check out the accessories Decide whether you want additional

functionality Determine whether synchronization of

data with other PDAs or personal computers is important

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HOW TO INSTALLA COMPUTER

Read the installation manuals before you start to install your equipment

Do some additional research Set up your computer in a well-designed

work area and remain aware of health issues as you work

Install your computer in a work space where you can control the temperature and humidity

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Set up your work space near an available electrical outlet and set aside a proper location for the electrical wires

Have a telephone outlet and telephone or cable connection near your work space so you can connect your modem and/or place calls while using your computer

If you plan to set up a wireless network, choose an area that is free from potential signal interference

Install bookshelves

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Obtain a computer tool set Save all the paperwork that comes with

your computer Record the serial numbers of all your

equipment and software Complete and mail your equipment and

software registration cards or register online

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Keep the shipping containers and packing materials for all your equipment

Identify device connectors Keep your computer area clean Check your home or renter’s insurance

policy

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HOW TO MAINTAINYOUR COMPUTER

Start a notebook or file using a simple outline that includes information about your computer

Before you work inside your computer, turn off the power and disconnect the equipment from the power source

Keep the area surrounding your computer dirt and dust free

Back up important files and data

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HOW TO MAINTAINYOUR COMPUTER

Protect your computer from viruses Keep your computer tuned Learn to use diagnostic tools Conserve energy wherever possible

Documents

Chapter 4