introduction to computer by farhan gul
TRANSCRIPT
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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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