chapter 8-8. embedded operating systems课件

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1、CHAPTER8OperatingSystemsandUtilityProgramsEmbeddedOperatingSystemsEmbeddedSystemOneofthemostimportantandwidelyusedcategoriesofoperatingsystemsHardwareandsoftwaredesignedtoperformadedicatedfunctionTightlycoupledtotheirenvironmentOften,embeddedsystemsarepartofalargersystemorproduct,E.G.antilockbrak

2、ingsysteminacar.ExamplesofEmbeddedDevicesEmbeddedSystemOrganizationDifferencesfromtypicalcomputerAvarietyofInterfaces.Useofadiagnostic.Specialpurposehardwaremaybeusedtoincreaseperformanceorsafety.Fieldprogrammable(FPGA),applicationspecific(ASIC),orevennon-digitalhardware.Singlepurposesoftware.C

3、haracteristicsofEmbeddedOSReal-timeoperationReactiveoperationConfigurabilityI/OdeviceflexibilityStreamlinedprotectionmechanismsDirectuseofinterruptsDevelopinganEmbeddedOSTwogeneralapproachesTakeanexistingOSandadaptitforembeddedpurposesDesignapurpose-builtOSsolelyforembeddeduseAdaptinganExistin

4、gOSExamplesincludeWindows,Linux,BSDGenerallyslowerthanspecialpurposeOSAdvantageisfamiliarinterfaceNeedtoaddreal-timecapabilityStreamliningoperationAddotherspecializedandnecessaryfunctionalityforthegivendevicePurpose-BuiltEmbeddedOSTypicalcharacteristicsinclude:fastandlightweightprocessorthreadsw

5、itchSchedulingpolicyisrealtimeanddispatchermoduleispartofschedulerSmallsizeRespondstoexternalinterruptsquicklyMinimizesintervalsduringwhichinterruptsaredisabledeCos:EmbeddedConfigurableOSOpensource,Royalty-freeReal-timeOSMostwidelyusedembeddedOSTargetedathigh-performancesmallembeddedsystems.Anem

6、beddedformofLinuxorothercommercialOSwouldnotprovidethestreamlinedsoftwarerequired.eCosConfigurationTooleCosConfigurationToolLoadinganeCosConfigurationeCosLayeredStructure