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1、Unit2ComputerArchitecture计算机体系结构SectionAComputerHardwareIntroductionComputerhardwareistheequipmentinvolvedinthefunctionofacomputerandconsistofthecomponentsthatcanbephysicallyhandled.Thefunctionofthesecomponentsistypicallydividedintothreemaincategories:input,output,andstorage.Co
2、mponentsinthesecategoriesconnecttomicroprocessors,specifically,thecomputer’scentralprocessingunit(CPU),theelectroniccircuitrythatprovidesthecomputationalabilityandcontrolofcomputer,viawiresorcircuitrycalledbus.Software,ontheotherhand,isthesetofinstructionacomputerusestomanipula
3、tedata,suchasaword-processingprogramoravideogame.Theseprogramsareusuallystoredandtransferredviathecomputer’shardwaretofromtheCPU.Softwarealsogovernshowthehardwareisutilized;forexample,howinformationisretrievedfromastoragedevice.Theinteractionbetweentheinputandoutputhardwareisco
4、ntrolledbysoftwarecalledtheBasicInput/OutputSystem(BIOS)software.Althoughmicroprocessorsarestilltechnicallyconsideredtobehardware,portionsoftheirfunctionarealsoassociatedwithcomputersoftware.Sincemicroprocessorshavebothhardwareandsoftwareaspects,theyarethereforeoftenreferredtoa
5、sfirmware.InputHardwareInputhardwareconsistofexternaldevices--thatis,componentsoutsideofthecomputer’sCPU–thatprovideinformationandinstructionstothecomputer.Alightpenisastyluswithalightsensitivetipthatisusedtodrawdirectlyonacomputer’svideoscreenortoselectinformationonthescreenby
6、pressingaclipinthelightpenorbypressingthelightpenagainstthesurfaceofthescreen.Thepencontainslightsensorsthatidentifywhichportionofthescreenitispassedover.Amouseisapointingdevicedesignedtobegrippedbyonehand.Ithasadetectiondevice(usuallyaball)onthebottomthatenablestheusertocontro
7、lthemotionofanon-screenpointer,orcursor,bymovingthemouseonaflatsurface.Asthedevicemovesacrossthesurface,thecursormovesacrossthescreen.Toselectitemsorchoosecommandsonthescreen,theuserpressesabuttononthemouse.Ajoystickisapointingdevicecomposedofaleverthatmovesinmultipledirections
8、tonavigateacursororothergraphicalobjectonacomputerscre
