必修2unit3computer课件
日期：2010-05-25 05:53
althoughconceivedlongbeforeelectronicstechnologyappeared，performingmathematicaloperations，Apersonalcomputer(PC)SpeakingWhatdotheyhaveincommon?Whichtypeofcomputeryoulikebest?Why?Whatdoyouusethecomputerfor?Listening1Listening2Listening3Ahugecomputer/supercomputerCharlesBabagge&hisDifferenceEngineAnalyticalEngine，wastohavebeencapableofstoringinstructions，theAnalyticalEngine，amechanicalcalculatingmachinethatwasconceivedbyBritishmathematicianandscientistCharlesBabbagein1833butonlyapartofwhichwaseverconstructedThefirstgeneral-purposedigitalcomputer，andusingpunchedcardsasaformofpermanentmemoryIn1936BritishmathematicianAlanTuringproposedtheideaofamachinethatcouldprocessequations方程式withouthumandirectionThemachineresembledanautomatic自动的typewriterthatusedsymbolsformathandlogicinsteadoflettersTuringintendedthedevicetobea“universalmachine”thatcouldbeusedtoduplicateorrepresentthefunctionofanyotherexistingmachineTuring’smachinewasthetheoreticalprecursortothemoderndigitalcomputerTheTuringmachinemodelisstill，
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