Computer Hardware Basic Input and Output Devices

8/9/2019 Computer Hardware Basic Input and Output Devices

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Basic Computer

Hardware


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Physical devices that make up the computerare called hardware. Computer’s hardwaredevices fall into the following categories:◦ Input and Output, Devices Expansion Cards

Storage Devices & Processing Devices

Hardware Defnition


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Input Devices

An input device is any hardware componentthat allows you to enter data andinstructions into a computer

Keyboard The keyboard is used to type information into the computer or input

information.

The keys on computer keyboards are often classied as follows:

Alphanumeric keys letters and numbers Punctuation keys

comma! period! semicolon! and so on. "pecial keys function keys!control keys! arrow keys! Caps #ock key! and so on.


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Input Devices cont!d"

#ouse◦ $ost modern computers today are run

using a mouse controlled pointer

Scanner◦

A scanner converts te%t&image into adigital le! allowing the computer toread and&or display the scanned ob'ect.

$ouc% Screen◦ (t’s a touch sensitive display device.

"ome models of desktop computersand notebook computers! includingnetbooks and Tablet PCs! and manymobile devices have touch "creen


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Touchpad◦ (t’s a small! )at! rectangular pointing

device that is sensitive to pressure andmotion. "ome touchpads have one ormore buttons around the edge of the

pad that work like mouse buttons.

Trackball◦ A trackball is a stationary pointing

device with a ball on its top or side. Tomove the pointer using a trackball! yourotate the ball with your thumb! ngers!

or the palm of your hand. *or users whohave limited desk space.


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Optica C%aracter 'ecognition usuallyabbreviated to OC'! is the electronic conversionof scanned or photographed images oftypewritten or printed te%t into computerreadable te%t. (t is widely used as a form of dataentry from some sort of original paper datasource! such as passports! documents! businesscard! or any number of printed records

Optica #ar( 'ecognition reads handdrawn

marks such as circles or rectangles. ,sed in paperbased (-#T"&T-*# e%ams.

http://en.wikipedia.org/wiki/Electronicshttp://en.wikipedia.org/wiki/Imagehttp://en.wikipedia.org/wiki/Imagehttp://en.wikipedia.org/wiki/Electronics


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)ar Code 'eader is an optical reader that uses laser beamsto read a bar code! or identication code. /hen you goshopping

#agnetic Stripe Card 'eader reads te%t printed withmagneti0ed ink. 1ou can see it under the checks given by your

bank.

*uto+ated $eer #ac%ine is a selfservice bankingmachine that connects to a host computer through a network.

A )io+etric device translates a personal characteristic intodigital code that is compared with a digital code stored in the

computer to identify an individual. A ngerprint readercaptures curves and indentations of a ngerprint. A facerecognition system captures a live face image


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Output Devices

utput devices are hardware componentsthat convey information to one or morepeople


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Output Devices cont!d"


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Expansion Cards

Sound Card◦ A sound card is an e%pansion card or integrated

circuit that provides a computer with the ability toproduce sound like music and voice that can beheard by the user.

-ideo Card◦ 5ideo cards plug into the motherboard and are used

to display video.

◦ 56A$ is video memory that enhances the

refreshment rate of the image.

◦ 5ideo cards have chipsets that can increase thespeed of video display.

.etwor( Inter/ace Card◦ Allow computers to connect together to

communicate with each other. 7etwork cards have

connections for cable! thin wire or wireless networks.


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Secondary Storage

◦ "torage: A location where informationcan be held permanently ortemporarily for later use.

◦ The harddrive is a mechanical storagedevice typically located internally.

◦ Characteristics

*ast recording and recovery of data

#arge storage capacity

$agnetic

"peed is measured in 6.P.$.’s26evolutions per minute3

Data Storage Devices0Secondary Storage


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◦ CD1'O# co+pact dis( readony +e+ory"

Compact disks or C8s can storelarge amounts of information. nedisk will store 9; $b or about gigabytes. 858 recorders allow youto store large les! such as movies!on a single disk. 858?6/ 2T-3


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2oppy dis(ette is magnetic

storage device for small

amounts of data 2@.>>$3.• A 3S) 4as% drive! sometimes

called a thumb drive! is a )ashmemory storage device thatplugs into a ," port on acomputer or mobile device

• An ExpressCard module is a

removable device mobile devicethat ts in an -%pressCard slot


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Data Storage Devices0 Pri+aryStorage

Pri+ary Storage

◦ '*# 2rando+ access+e+ory3 stores data that isprocessing. This type of memoryis erased when the computer isturned oB.

◦ 'O# 2read ony +e+ory3contains special instructions forthe computer to operate.

◦

Cac%e +e+ory increases thespeed of the processor byrecording and anticipatinginstructions.


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Data Storage Devices0 Pri+aryStorage

◦ Computer memory is binary 2; or @3 2on or oB3.

◦ The byte is the standard unit of measurement.

◦ A byte is composed of = bits 2binary digits3.

◦

Typical units of measurement: @ 2kilobyte3 D @;;; bytes @ $ 2megabyte3 D@;;; kilobytes or @ million

bytes @ E 2gigabyte3 D@;;; megabytes or @ billion

bytes @ Tb2Terabyte3D @;;; gigabytes or @ trillon


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Processing 3nit cont!d"◦

CP, 2Central Processing ,nit3 also called the$icroprocessor or FThe rainG of the Computer.

◦ Processor speed: The speed at which amicroprocessor e%ecutes instructions. This isusually measured in megahert0 2$H03&Eigahert02EH03.

◦ Currently the processors 2iI!i! and i


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Processing 3nit cont!d"

◦ Computer chips contain millions oftransistors. They are small pieces of

semiconducting material 2silicon3.

◦ An integrated circuit is embedded in

the silicon. Computers are made ofmany chips on a circuit board.


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Ports and Perip%eras

Ports are an interface between the computer and another peripheraldevice such as a disk drive! mouse! printer! modem! monitor! camera!*#A"H drive or keyboard.

Examples:

"erial

Parallel

hotwire

,"


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Ports and Perip%erascont!d"Peripherals are devices

that plug into acomputer and are nothoused internally.

Examples:Printers

"canners

Cameras


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Co+parison )etween SecondaryStorage

$ype o/Secondary

Storage

Capacity $rans/erSpeed

Portabe Categories

Hard 8isk8rive

5ery High2@;; E3

5ery *ast 7o

C82Compact8isk3

High 29;$3

*ast 1es C86$C86/

85828igital5ersatile

8isk3

5ery High2> E3

*ast 1es 858 ? 6/

*loppy 8isk #ow 2@.>>$3

"low 1es

," *lash 5ery High *ast 1es

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