OSEK_VDX Operating System

OSEK/VDXOperatingSystemSpecification2.2.22OSEKOS2.2.22©byOSEKDocument:OS222.docOSEK/VDXOperatingSystemVersion2.2.2July5th,2004Thisdocumentisanofficialreleaseandreplacesallpreviouslydistributeddocuments.TheOSEKgroupretainstherighttomakechangestothisdocumentwithoutnoticeanddoesnotacceptanyliabilityforerrors.Allrightsreserved.Nopartofthisdocumentmaybereproduced,inanyformorbyanymeans,withoutpermissioninwritingfromtheOSEK/VDXsteeringcommittee.OSEK/VDXOperatingSystemSpecification2.2.2OSEKOS2.2.22©byOSEK2PrefaceOSEK/VDXisajointprojectoftheautomotiveindustry.Itaimsatanindustrystandardforanopen-endedarchitecturefordistributedcontrolunitsinvehicles.FordetailedinformationaboutOSEKprojectgoalsandpartners,pleaserefertothe“OSEKBindingSpecification”.Thisdocumentdescribestheconceptofareal-timeoperatingsystem,capableofmultitasking,whichcanbeusedformotorvehicles.Itisnotaproductdescriptionwhichrelatestoaspecificimplementation.ThisdocumentalsospecifiestheOSEKoperatingsystem-ApplicationProgramInterface.Generalconventions,explanationsoftermsandabbreviationshavebeencompiledintheadditionalinter-projectOSEKOverallGlossarywhichispartoftheOSEKBindingSpecification.RegardingimplementationandsystemgenerationaspectspleaserefertotheOSEKImplementationLanguage(OIL)specification.OSEK/VDXOperatingSystemSpecification2.2.22OSEKOS2.2.22©byOSEK3TableofContents1Introduction...........................................................................................................................11.1Systemphilosophy.......................................................................................................61.2Purposeofthisdocument.............................................................................................81.3Structureofthisdocument...........................................................................................92Summary.............................................................................................................................113ArchitectureoftheOSEKoperatingsystem.......................................................................123.1Processinglevels........................................................................................................123.2Conformanceclasses..................................................................................................133.3RelationshipbetweenOSEKOSandOSEKtimeOS................................................154Taskmanagement...............................................................................................................164.1Taskconcept...............................................................................................................164.2Taskstatemodel.........................................................................................................164.2.1Extendedtasks..................................................................................................164.2.2Basictasks.........................................................................................................184.2.3Comparisonofthetasktypes............................................................................184.3Activatingatask.........................................................................................................194.4Taskswitchingmechanism........................................................................................194.5Taskpriority...............................................................................................................194.6Schedulingpolicy.......................................................................................................204.6.1Fullpreemptivescheduling...............................................................................204.6.2Nonpreemptivescheduling..............................................................................214.6.3Groupsoftasks.................................................................................................224.6.4Mixedpreemptivescheduling...........................................................................234.6.5Selectingtheschedulingpolicy........................................................................234.7Terminationoftasks...................................................................................................235Applicationmodes..............................................................................................................245.1Scopeofapplicationmodes........................................................................................245.2Startupperformance..................................................................................................245.3Supportforapplicationmodes...................................................................................246Interruptprocessing............................................................................................................257Eventmechanism..................................................................