copyright 2002, paradigm publishing inc. hardware: enabling the information processing cycle

Copyright 2002, Paradigm Publishing Inc.

Hardware: Enabling the Information Processing Cycle

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Topics

Topics

System Unit Hardware

Input Hardware

Output Hardware

Storage Devices

Large Computer Hardware

On the Horizon

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Embedded Computer

A specialized computer that is part of a larger system, device, or machineTiny circuit boards (chips) that are essential to the operation of the device– contain instructions that enable the device

to function properly

Use continues to expand with increasing Internet use and desire for mobile access

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What is Hardware?

all of the physical devices or equipment you can seethat make up a computerized system

all of the physical devices or equipment you can seethat make up a computerized system

larger and more complex system requireslarger number of devices to support its functions

larger and more complex system requireslarger number of devices to support its functions

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System Unit Hardware

main part of a PC system

contains components necessary for processing information

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The Motherboard

A thin sheet of fiberglass with electrical pathways (traces) etched to connect components

microprocessor

system clock

sockets for RAM

ROM chips

expansion slots

ports

buses

power supply

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Microprocessors

Also referred to as a central processing unit (CPU) or the brainElectronic chips are also called integrated circuits

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RAM Chips

Also called main memoryMain memory consists of a group of electronic chips inside the system unit– stores programs while they are being

executed– stores data while it is being processed

Large programs require lots of main memory– additional chips can be installed

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Measuring RAM Capacities

Computer MemoryComparisons

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Cache Memory

Secondary type of processing storage used with RAM– holding area where most recently called instructions

and data are stored– shortens processing time

Level 1built into

the architecture

Level 2same as Level 1 or

may consist of high-speedSRAM chips on motherboard

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ROM Chips

Contain instructions or data permanently placed on the chip by the manufacturerCan only be read, not altered or erased, and are nonvolatile (do not need constant power supply) BIOS

basic input/output systemprogram that boots the computer and

communicates with components

BIOSbasic input/output system

program that boots the computer andcommunicates with components

POSTpower-on self test

contains instructions to check physical components

POSTpower-on self test

contains instructions to check physical components

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Other System Unit HardwarePort– external plug-in slot used

to connect a device– serial, parallel, video,

USB, SCSI– docking station is an

accessory that provides additional ports

Expansion slot– slot is an opening to allow

insertion of a board– sound, video, network

interface, graphics, modem

PC Card– plugs into a portable

computer– Type I = additional

memory– Type II = network or

sound– Type III = removable hard

drive

Bus– electronic path along

which bits are transmitted

– size is referred to as bus bandwidth

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Topics

Input Hardware

the hardware device that allows users toenter programs, data, and commands

the hardware device that allows users toenter programs, data, and commands

the program or application being used determinesthe type of input device needed

the program or application being used determinesthe type of input device needed

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Alphanumeric Keyboard

special-purpose keys

function keys numeric keypad

cursor-control keys

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Special-Purpose Keyboard

used by businessesto increase user

efficiency

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Mouse

make selections from a menu and activate programs

optical mouseuses a light

sensorto track

movementfoot mouse

for people with hand

and wrist injuries

mouse pad

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Trackball

Similar to a mouse (upside-down)Remains stationary – user moves the ball to move the pointer on the screenRequires less desk space and arm movement

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Touch Pad and Touch ScreenTouch Pad

Small, flat device sensitive to touch, pressure, motionOne part acts as a button; other functions like the surface of a mouse padUsed in many portable computers

Touch ScreenAllows user to make selections by pressing finger against the chosen option on the screenUsed in ATMs and kiosks at retail outlets

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Joystick

Small box containing a vertical leverMoves the cursor on the screen when pushed in a certain directionOften used for computer gamesPointing lever is a new type used for notebooks– eliminates external mouse or

joystick– allows hand to remain close to

keyboard

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Pen and Tablet

Digitizing pen with drawing tablet is used when precise control over an input device is requiredPDAs use a special pen– choose menu options – write information on

the screen

Graphics tablet used to trace precise or detailed drawings– hundreds of intersecting

wires are embedded in the flat surface

– intersection represents specific location (address) with values of 0 and 1 (1 when touched by pen)

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Optical Scanner

A light-sensing electronic deviceUses lasers to read and capture printed text and images and stores as a fileMatrix of rows and columns of dots called a bitmapQuality is determined by the resolution– each dot consists of one or more bits of data; the more

bits, the clearer the image– higher number of dots (pixels) per inch (dpi) results in

sharper and clearer image– home/office models use a resolution of at least 1,200 dpi

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Optical Scanner…/2Intelligent scanner– uses optical character

recognition (OCR) software so changes can be made

Dumb scanner– can only capture and input

Handheld scanner– moves the scanner across

the materialFlatbed scanner– pages are laid on the

scanner’s surface (or fed through) and the device inside moves

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Optical Scanner…/3

Bar code reader – common for commercial use with a Universal Product Code (UPC)– form of a pen or placed below a glass cover– computer uses number to locate information

about the product like name or price

Optical reader – to pay for purchases– cash cards – store cash in digital form– smart cards – contain electronic memory

(store cash, as well as other information)

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Audio Input

process of entering (recording)speech, music, or sound effects

must have sound card, sound capturing device,speakers, and special software

voice recognitionrecognizes preprogrammed wordsstored in a database by different individuals (speaker-independent)

speech recognitionrecords speech in digital form in a

database that can be used again usually by the same person (speaker-dependent)

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Video Input

Uses a special type of video camera that is plugged into a video capture card– converts the analog video signal to a digital

signal

Video can also be live or recorded using a video camera and a special processing boardBusinesses, government, and organizations are discovering numerous video-input applications

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Topics

Digital CameraCaptures and stores an image in a digital format– flash memory– floppy disk

Photo-editing software available to adjust color and sizeQuality is measured by resolution (same as scanners)– usually advertised in

megapixels (millions of pixels)

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Output Hardware

hard copypermanent version

(printout)

soft copytemporary version(display on screen)

processed data that can beused or stored

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Cathode Ray Tube (CRT) Monitor

Most common type– large, sealed glass tube housed in a plastic case– front of the tube is the screen, cable at the rear of

monitor plugs into graphics adapter board, electric cord into outlet

RGB – Red, Green, Blue– contained in each dot of phosphor material on screen– three dots make up a pixel– electron beam moves back and forth across rear of

screen causing dots on front to glow

Video card converts digital signals to analog signals

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Flat-Panel Display

Smaller, lighter, thinner, and consumes less powerLiquid crystal display (LCD)– liquid crystals are sandwiched between

sheets of material– electric current passes through crystals,

causes them to twist– effect blocks some light waves and allows

others to pass through– uses digital signals

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Display Goggles

Effective for computer games Allow mobile workers to perform without having to stop to use a computer (hands-free)Data and information are displayed on a headset-mounted full-color video console

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Most common device for hard-copy outputCategories– impact – strikes an inked ribbon against the paper– nonimpact – uses electricity, heat, laser technology,

or photographic techniques to form images

Three types include a range of printers that vary in quality of output and printing speed

Printers

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Dot-Matrix PrintersTiny dots form imagesPrint head strikes inked ribbon, deposits on pageResolution measured in dpi– draft or letter quality

Print head contains pins– more pins = higher quality

Prints one character at a time– speed measured by cps

Capable of printing multi-part forms

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Ink-Jet Printers

Sprays thousands of tiny droplets of electrically charged ink to form imagesResolution measured in dpiSpeed measured in ppm

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Laser PrintersExceptional qualityMechanism reads characters and sends to laser deviceLaser sends light signals through mirrors in the drum, creating tiny dots of lightDots create magnetic fields on drum (matches shape) which attracts toner powerToner pressed onto paper as drum rotates

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Plotters

To produce specialized kinds of large-sized, high-quality printingImage consists of a series of tightly packed tiny dotsToner is fused onto paper when electrically charged wires come into contact with specially coated paper

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Speakers

Speakers

warning sounds computer games audio e-mail distance learning videoconferencing

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Storage Devices

Permanent storage consists of devices and media used for permanent recordings– also called secondary, auxiliary, or external storage

Consists of two main parts– storage device

• hardware component that houses a storage medium

– storage medium• where data is recorded

Usually built into a PC systemTwo main types– magnetic– optical

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Categories– permanent – attached to

system unit (e.g. hard disk)

– removable – can be removed/replaced (e.g. floppy disk)

How stored data is accessed– sequentially – in the order

in which data was stored– directly – in any order,

randomly

Access time– time spent locating a file

Data transfer rate– speed at which data is

transferred from memory or storage device

Work by applying electrical charges to iron filings on the surface medium– either magnetized (1-bit)

or not magnetized (0-bit)

Magnetic Storage Devices

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Floppy Disks and Disk Drives

A thin, circular Mylar wafer between two sheets of special cleaning tissue inside a plastic caseData is stored along tracks and sectors– track – a numbered concentric circle– sector – a numbered section or portion; group = cluster

Computer maintains a file directory of the file name, size, and sector in which the file begins– called a file allocation table (FAT file)

Higher-capacity floppy disks– SuperDisk, Zip, HiFD

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How a Floppy Disk Drive Works

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Formatting a Floppy Disk

Must be formatted by manufacturer or userHow a disk is formatted is determined by disk drive and operating systemDisk surface is arranged into– tracks– sectors– clusters

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Handling a Floppy Disk

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Hard Disks and Hard DrivesConsist of– one or more rigid metal

platters (disks) – disks mounted on a

metal shaft in a container

– an access mechanism

Sealed to prevent contaminationFixed or interchangeable– Jaz cartridge

Usually preformatted– can be reformatted

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Comparing Floppy Disks and Hard Drives

Floppy Disksstorage capacity: megabytes

spins only when datais being stored

or accessed

Hard Disksgreater storage capacities:

gigabytesoperates much faster;

rotates fastercontinues spinning whilecomputer is in operation

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Tape Cartridges and Tape Drives

One of the first typesUsed mainly for – backing up the contents of a hard drive– archiving large amounts of data

Small plastic housing containing a magnetically coated ribbon of thin plasticTape drive is used to read and write dataRelatively inexpensiveSequential-access type of storage

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Optical disk– also called compact disk (CD)– a plastic disk that is 4.75 inches in diameter

Optical disk drive– can read almost any kind of data recorded

Data stored along a single track in sectors– spirals outward from the center to the outer

edge

Available in a variety of formats– not necessarily compatible with one another

Optical Disks and Disk Drives

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Types and Storage Capacities of Optical Disks

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Large Computer Hardware

MagneticDisk pack– mounted inside a disk

drive– metal shaft extends

through center of vertically aligned disks

– provides direct access

Magnetic tape– removable reels– contains tracks that

extend the full length of the tape

– sequential access

OpticalWORM– write once, read many

disks– mainly found in

mainframe applications

– high-capacity– usually only readable

by the drive on which they were written

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On the Horizon

Wireless, Wireless,and MoreWireless

Increased MagneticData Storage

Capacities

ImprovedMonitors

MoreSmart Cards

BiometricAuthentication

Devices asSecurity Measures

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copyright 2002, paradigm publishing inc. hardware: enabling the information processing cycle

Documents

paradigm publishing

larger system

topics ram chips

complex system

topics rom chips

pc system

motherboard slide

computerized system