《計(jì)算機(jī)英語(yǔ)》課件Chapter 1 Introduction to Information Technology

?計(jì)算機(jī)英語(yǔ)?課件Chapter1IntroductiontoInformationTechnologyChapter1IntroductionInformationTechnologyObjectiveAfterreadingthischapter,youshouldbeableto:Definewhatthedigitalcomputeris.Knowtheevolutionofcomputer.Describethefivetypesofcomputer.Knowtheseveraltypesofdata.Explainthefivepartsofaninformationsystem.1.1DigitalComputerAllgeneral-purposecomputersrequirethefollowinghardwarecomponents:Centralprocessingunit(CPU).

Memory(fast,expensive,short-termmemory).Massstoragedevice(slower,cheaper,long-termmemory).

Inputdevice.

Outputdevice.

1.2EvolutionofComputerFromthefirstlarge-scaleelectroniccomputerwasbuilt,computershavedevelopedthroughfivegenerations.1.2.1FirstGeneration(1944-1958):VacuumTubes1.2.2SecondGeneration(1959-1964):Transistor1.2.3ThirdGeneration(1964-1970):IntegratedCircuits1.2.4FourthGeneration(1971-Present):VLSIintegratedcircuits1.2.5FifthGeneration(PresentandBeyond):ArtificialIntelligenceFifthgenerationcomputingdevices,basedonartificialintelligence,arestillindevelopment.1.3TypesofComputers1.3.1SupercomputersThesupercomputeristhetopoftheheapinpowerandexpense.Thistypeofcomputerusuallycostshundredsofthousandsorevenmillionsofdollars.Asupercomputerisacomputerthatisatthefrontlineofcurrentprocessingcapacity,particularlyspeedofcalculation.1.3.1SupercomputersThetermsupercomputeritselfisratherfluid,andtoday'ssupercomputertendstobecometomorrow'sordinarycomputer.1.3.1SupercomputersSupercomputersareusedforhighlycalculation-intensivetaskssuchasproblemsinvolvingweatherforecasting,climateresearch,molecularmodeling(computingthestructuresandpropertiesofchemicalcompounds,biologicalmacromolecules,polymers,andcrystals),physicalsimulations(suchassimulationofairplanesinwindtunnels.),cryptanalysis,andthelike.1.3.2MainframeComputersThemainframecomputerisapowerfulmulti-usercomputercapableofsupportingmanyhundredsorthousandsofuserssimultaneously.1.3.2MainframeComputersTodayinpractice,thetermusuallyreferstocomputerscompatiblewiththeIBMSystem/360line,firstintroducedin1965.(IBMSystemz10isthelatestincarnation.)1.3.2MainframeComputersMainframesarecomputersusedmainlybylargeorganizationsforcriticalapplications,typicallybulkdataprocessingsuchascensus,industryandconsumerstatistics,ERP,andfinancialtransactionprocessing.1.3.3MinicomputersItisamidsizecomputer.Theterm"minicomputer"evolvedinthe1960stodescribethe"small"thirdgenerationcomputersthatbecamepossiblewiththeuseoftransistorandcorememorytechnologies.1.3.3MinicomputersAndalthoughtoday’sPCsandserversareclearlymicrocomputersphysically,architecturallytheirCPUsandoperatingsystemshaveevolvedlargelybyintegratingfeaturesfromminicomputers.1.3.4MicrocomputersMicrocomputersaretheleastpowerful,yetarethemostwidelyusedandfastest-growingtypeofcomputer.Amicrocomputerisacomputerwithamicroprocessorasitscentralprocessingunit.Anothergeneralcharacteristicofthesecomputersisthattheyoccupyphysicallysmallamountsofspacewhencomparedtomainframeandminicomputers.1.3.4Microcomputer