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1、AFirstBookofANSICFourthEditionChapter1IntroductiontoComputerProgrammingObjectivesHistoryandHardwareProgrammingLanguagesAlgorithmsTheSoftwareDevelopmentProcessCaseStudy:DesignandDevelopmentCommonProgrammingErrors2AFirstBookofANSIC,FourthEditionHistoryandH
2、ardwareBabbage’sanalyticalengine(1822)Atanasoff-BerryComputer(ABC,1937)HumanoperatormanipulatedexternalwiringElectricalNumericalIntegratorandComputer(ENIAC,1946)VacuumtubesMarkI(1944)MechanicalrelayswitchesElectronicDelayedStorageAutomaticComputer(EDSAC,
3、1949)Incorporatedaformofmemory3AFirstBookofANSIC,FourthEditionHistoryandHardware(continued)4AFirstBookofANSIC,FourthEditionComputerHardwareComputersareconstructedfromphysicalcomponentsreferredtoashardwareHardwarefacilitatesthestorageandprocessingofdataun
4、derthedirectionofastoredprogramComputerhardwaredoesnotstoredatausingthesamesymbolsthathumansdo5AFirstBookofANSIC,FourthEditionBitsandBytesThesmallestandmostbasicdataiteminacomputerisabitOpenorclosedswitch0or1Thegroupingof8bitstoformalargerunitisreferredt
5、oasabyteCanrepresentanyoneof256distinctpatternsThecollectionsofpatternsconsistingof0sand1susedtorepresentletters,singledigits,andothersinglecharactersarecalledcharactercodes6AFirstBookofANSIC,FourthEditionComponents7AFirstBookofANSIC,FourthEditionMainMem
6、oryUnitStoresdataandinstructionsassequenceofbytesAprogrammustresideinmainmemoryifitistooperateonthecomputerCombines1ormorebytesintoasingleunit,referredtoasawordConstructedasrandomaccessmemory,orRAMEverysectionofmemorycanbeaccessedrandomlyasquicklyasanyot
7、hersectionVolatile:dataislostwhenpoweristurnedoffSizeisusuallyspecifiedinbytes(MBorGB)8AFirstBookofANSIC,FourthEditionCentralProcessingUnit(CPU)Controlunit:directsandmonitorstheoveralloperationofthecomputerKeepstrackofwherethenextinstructionresidesIssues
8、thesignalsneededtobothreaddatafromandwritedatatootherunitsinthesystemExecutesallinstructionsArithmeticandLogicUnit(ALU):performsallofthecomputations,suchasaddition,subtraction,comparisons,andsoon,thatacomputerprovidesCPUsa