东北大学实时系统课件.ppt

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1、Real-TimeSystemsNanGuan（关楠）ComputingEvolutionMainframecomputing(60’s-70’s)LargecomputerstoexecutebigdataprocessingapplicationsDesktopcomputing&Internet(80’s-90’s)Onecomputerateverydesktodobusiness/personalactivitiesEmbeddedSystems(since00’s)Numerouscomputingdevicesineveryplace/per

2、son“Invisible”partoftheenvironmentMillionsfordesktopsvs.billionsforembeddedprocessorsEmbeddedSystems“Computersystemsthatareembeddedintophysicalobjectes……”98%computersintheworldareembeddedsystemsMarketshare3EmbeddedSystemsReal-TimeSystemsReal-TimeSystems:“Thecorrectnessofthecomputa

3、tiondoesnotonlydependonthelogicalresults,butalsothetimewhentheresultsareproduced.”Real-TimeSystemsarecommoninEmbeddedSystemsInteractionbetweencomputersandthephysicalworldReal-TimeSystemsReal-TimeSystemsReal-TimeSystemsReal-TimeSystemsReal-TimeSystemsWeneedtoguaranteethatalltimingc

4、onstraintsaresatisfiedunderanycircumstance,BEFORErun-timeHowtodothis？Howaboutusingaveryfastprocessor?Howaboutexecutingitandmeasuringthetime?(Testing)11ThestoryaboutasheepinScotland…12ThestoryaboutthePathfinderonMars…Whatdowelearn?Testingisinadequate13Whatdowelearn?Testingisinadequ

5、ate,especiallyforreal-timeembeddedsystemsNeedtosimulatethestimulusandfeedbackfromthephysicalworld14EventheNASALabfails,thenhowaboutyourproject?Whatdowelearn?Difficulttofixtheerror,evenifitisexposedintestingDifficulttoreproduceDifficulttoexplain15TimingAnalysisHowtorigorouslyverify

6、thetimingcorrectness？Anextremelydifficultproblem…16Real-TimeComputingTechnologySomeleadingcountriesUSAGermanySwedenFranceItaly……17ResearchinReal-TimeSystemsConferencesRTSS:IEEEReal-TimeSystemsSymposiumRTAS:IEEEReal-TimeandTechnologyandApplicationsSymposiumECRTS:EuromicroConference

7、onReal-timeSystemsJournal:JournalofReal-TimeSystems18MoredetailsaboutReal-TimeSystemsinthefollowing19HardvsSoftReal-TimeSystemsDefinitionbasedonfunctionalcriticalityHARD:ThefailuretomeetthetimingconstraintshasdisastrousconsequencesBrakingsystem,collisiondetection,etc.SOFT:Afewmiss

8、esofdeadlinesdonoseriousharm,ando