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CHAPTER ONEINTODUCTION TO COMPUTER

FARHAN GUL

Manisstillthemostextraordinarycomputerofall

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Expertsagreethatthebesttypeofcomputerforyourindividualneedsisonethatcomesonthemarketabouttwodaysafteryouactuallypurchasesomeothercomputer.

Mycomputermustbebroken:wheneverIaskawrongquestion,itgivesawronganswer

DefinitionofComputer.

ComputerIsElectronicdeviceoperatingunderthecontrolofinstructionsstoredinitsownmemory.

Byinstructionswemeansoftwareoraprogram.

ComputercanbedefineasItisanelectronicdevicewhichacceptdatastoreitinitsmemory(Temporary,Permanent)processthatdataandgivetheoutputofthe

entereddata.Acomputernevermakesamistaketheprocesseddataofcomputer

dependsontheinputdata.

Usesofcomputerinoursociety

Computersystemisnowadaysalmostusedineveryfieldoflife.Someexamplesof

computerapplicationinsocietyareasfollow.

Education,Finance,Government,Healthcare,Science,Publishing,Travel,Industry

Computersystembasicallydealswithfourtypesofdata.Whichareasfollow

TextualData(A-Z)(a-z)(0-9)(SpecialCharacters)

GraphicalData(Pictures,Graphics)

PhonicData(Audio).

VideoData

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Whatisthesystemunit?

Box-likecasecontainingelectroniccomponentsusedtoprocessdata

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ComponentsofaComputerSystem

Dataisasetofinformation.Itcanberepresentedindifferentforms.Thebasicformsofdataaretextualdata,graphicdata,phonicdataandvideodata. Useristhepersonwhousecomputertosolvehisproblem. Hardwareisalsoapartofcomputerthatisusedtocommunicatetothe

computersystem.Computerhardwareisofthreetypes*inputdevices*OutputDevices*I/ODevices.

Softwareisacomputerprogramorwecansaysoftwareisthesetofinstructionsthattellsthecomputerwhattodo.Softwarearealsoofthreetypes*ApplicationSoftware*SystemSoftware*LanguageSoftware.

Componentsofacomputersystemare

ProcessorC.P.U Mainmemory

Secondarymemory

Inputdevices Outputdevices

1.WhatisProcessor(C.P.U)?

ProcessororCentralProcessingUnit(C.P.U)isthebasicpartofacomputersystem.

Processorisalsocalledthebrainofcomputersystem.Thispartofcomputerisanimportantcomponent.AlltheOperationsinsideacomputerareperformby

Processer.Acomputerprocessorconsistsofthreebasicparts.WhichareAU,LUandCU.

*AUstandsforArithmeticalUnit

*LUStandsForLogicalUnit*

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2.WhatisMainMemory?

MainMemoryofcomputerisnormallyreferstoMemoryofcomputer.MainMemory

istheplacewheretheinstructionarestoredthataretobeexecutedbytheprocessor.Primarymemoryisdirectlyconnectedtotheprocessor.

ThetermComputermemorynormallyreferstoRAM.Howevertherearevariousothertypesofmemoryinsideacomputer.

Belowisadiagrammaticalrepresentationofcomputermemorythatwillbe

furtherexplainedinchapter`ComputerMemory`.

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WhatisRAM?

RAMstandsforRandomAccessMemory.RAMisacomputerMemory.RAMisastoragelocationfromwherethedatacanbeaccessinanyorder.RAMisaTemporaryMemory.IethecontentsoftheRAMarestoreaslongasthe

computeristurnedONoraprocessisexecuting.ThecontentsofRAMwashedoutwiththefailureofelectriccurrent.RAMisalsocalledVolatileMemory.OrwashableMemory.

TypesofRAM.

TherearebasicallythreetypesofRAM.

SDRAM,DDRandRambusDRAM.

3.Secondarymemory

ThetypeofcomputermemoryexceptRamiscalledsecondarymemory.Secondary

memoryispermanentmemoryofcomputer.Thecontentsofsecondarystoragedevicesremainaslongastheuserremovesit.Harddiskisasecondarystorage

devicethatisattachedtoCPU.ButCPUdoesnotaccessdatadirectlyfromsecondarystoragedevices.Thecomputerusuallyusesinput/outputchannelstoaccess

secondarystoragedevices.Therearetoomanytypesofsecondarystoragedevices

thatwillbediscussedinchaptercomputerMemory.

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4.InputDevices

Inputdevicesareusedtocommunicatetocomputersystem.Thesedevicesareused

toenterdatatocomputer.Thereareavarietyofinputdevicesthatareexplainedinchapter3ComputerHardware.Somebasicinputsarekeyboard,mouse,scanner,

joystick,lightetc

5.OutputDevices

Outputdevicesareusedtocommunicatetocomputersystem.Thesedevicesareusedtoshow/displaytheresultofourinputdata.Thereareavarietyofoutput

devicesthatareexplainedinchapter3ComputerHardware.SomebasicoutputdevicesareMonitor,Speaker,Projector,Printer,Plotteretc

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TypesofComputers

Computerscanbegenerallyclassifiedbysizepowerandprice.

Computertypescanbedividedinto3categoriesaccordingtoelectronicnature.

TypesofcomputersareclassifiedaccordingtohowaparticularComputerfunctions.

Thebasictypesofcomputeraregivenbelow.

AnalogueComputers

DigitalComputers

HybridComputers

1. AnalogueComputers

AnalogueComputerWorksonanaloguesignals.Analoguesignalsarerepresented

byacontinuoussetofvaryingvoltagesanaloguecomputersperformscalculationin

asingleprocessthatiswhythereisnoneedofstoragecapabilityinthese

computers.Analoguecomputersarenowadaysusedforscientificresearch,in

hospitalsandinflightcenters.Thesecomputersmeasurephysicalquantitiessuchas

Speed,Velocity,Acceleration,time,temperatureetc.

Figure:ElectronicAnalogueComputer

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2. DigitalComputer

Digitalcomputersarethosecomputers,whichworksonBinaryLanguage(Binary

languageisthenativelanguageofadigitalcomputer).Therearetwoinputs,states

ofdigitalcomputeri.e1=Onand0=Off.Withdigitaltypeofcomputersdatais

representedbydigitalof0and1orOFFstateandONstate.Digitalcomputersare

highspeedprogrammable;theycomputevaluesandstoresresults.*DigitalSignals

areDiscrete

AV-7624whitehallcomputer

HybridComputers

HybridcomputerareveryuniqueComputers,BecauseTheseComputerscombines

thebestfeaturesofbothDigitalandAnalogueComputers.ThedigitalcomponentsofHybridComputernormallyservesasthecontrollerandprovidesLogical

Operations,whiletheanalogcomponentsnormallyservesasasolverof

differentialequations.

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UsesOfComputer

Acomputerisanelectronicdevice,whichexecutessoftwareprograms.It

consistsof2parts-hardwareandsoftware.Thecomputerprocessesinput

throughinputdeviceslikemouseandkeyboard.Thecomputerdisplays

outputthroughoutputdeviceslikecolormonitorandprinter.Thesizeofacomputervariesfromverysmalltoverybig.Thespeedofcomputersalsohas

averylargerange.Millionsofpeopleusecomputersallovertheworld.

Thereareseveralusesofcomputers: 1.WordProcessing

WordProcessingSoftwareareusedforTypingPurposes.These

areBasicallysoftware,whichautomaticallycorrectsspellingand

grammarmistakes.Ifthecontentofadocumentrepeatsyoudonthave

totypeiteachtime.Youcanusethecopyandpastefeatures.Youcan

printoutdocumentsandmakeseveralcopies.Itiseasiertoreada

word-processeddocumentthanahandwrittenone.Youcanadd

imagestoyourdocument.

2.Internet Itisanetworkofalmostallthecomputersintheworld.Youcan

browsethroughmuchmoreinformationthanyoucoulddoinalibrary.

Thatisbecausecomputerscanstorealargeamountofinformation.InternetisarichSourceofinformation.ThroughE-Mailyoucan

communicatewithapersonsittingthousandsofmilesawayinseconds.

Thereischatsoftwarethatenablesonetochatwithanotherpersonon

areal-timebasis.Videoconferencingisalsopossiblewiththehelpof

Internet.

3.Desktoppublishing-Withdesktoppublishing,youcancreatepagelayoutsforentirebooksonyourpersonalcomputer.

4.Digitalvideooraudiocomposition Audioorvideocompositionandeditinghavebeenmademucheasierbycomputers.ItnolongercoststhousandsofRupeesof

equipmenttocomposemusicormakeafilm.Graphicsengineerscan

usecomputerstogenerateshortorfull-lengthfilmsoreventocreate

three-dimensionalmodels(3D).Anybodyowningacomputercannow

enterthefieldofmediaproduction.Specialeffectsinsciencefiction

andactionmoviesarecreatedusingcomputers.

5.ComputersinMedicine

Youcandiagnosediseases.Youcanlearnthecures.Softwareis

usedtoexaminetheinternalorgansofthehumanbody.Softwareis

usedforperformingsurgery.Computersareusedtostorepatientdata.

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6.MathematicalCalculations Usingacomputerwecansolvethecomplexproblemsofmathematics.

Todayscomputersarefastenoughtocalculatemillionsofthebiggest

problemsofmathematicspersecond.

7.Travel

Onecanbookairticketsorrailwayticketsandmakehotelreservationsonline.

8.Telecommunication Theprocessofsendinginformationfromonelocationtoanother

locationispossiblewiththehelpofcomputer.Softwareiswidelyusedin

telecommunication.Alsoallmobilephoneshavesoftwareembeddedin

them.

9.E-Learning InsteadofabookitiseasiertolearnfromanE-learningsoftware.One

canaccessinformationusingE-BooksorE-Generals.E-LearningisAlso

refertoCBT

CBTStandsforComputerBasedTraining

10. Examinations- Youcangiveonlineexamsandgetinstantresults.Youcancheckyourexaminationresultsonline.

*WWW.BISEP.ComistheBestexamplewherewecanseeonlineresultsof

SSCandFA,FSC.11. ATMmachines

Thecomputersoftwareauthenticatestheuseranddispensescash.

12. News Therearemanywebsitesthroughwhichyoucanreadthelatestorold

news.

13. RoboticsRobotsarecontrolledbysoftware.

14. WashingMachinesTheyoperateusingsoftware.

15. MicrowaveOven Theyareoperatedbysoftware.

16. Weatheranalysis Supercomputersareusedtoanalyzeandpredictweather.

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