lecture_3_introduction_and_componentsnew

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1、AdvancedOperatingSystems----OverviewofOSZhaoFangOperatingSystems-forthegraduatestudentsGoalsforToday•OperatingSystemscomponents•OperatingSystemsServices•OperatingSystemsStructures•OperatingSystemsOrganizationsThelayersofaComputerSystemHumansProgramInterfa

2、ceUserProgramsO.S.InterfaceO.S.HardwareInterface/PrivilegedInstructionsDisk/Tape/MemoryForEachOSComponent•Therearetwomajordesignquestions:–Whatisthehardwareinterface?•Thephysicalreality–Whatistheapplicationinterface?•ThenicerabstractionComputerSystemOrgan

3、izationRealityvs.AbstractionRealityAbstractionAsingleCPUMultipleCPUsLimitedRAMcapacityInfinitecapacityMechanicaldiskMemoryspeedaccessInsecureandReliableandsecureunreliablenetworksManyphysicalAsinglemachinemachinesOperatingSystemsComponents•ProcessManageme

4、nt•Main-MemoryManagement•FileManagement•I/OSystemmanagement•Secondary-StorageManagement•Networking•ProtectionSystem•UserInterfacesProcessManagement•Aprocessisaprograminexecution.•Aprocessisaunitofworkinasystem.•Theoperatingsystemisresponsibleforthefollowi

5、ngactivitiesinconnectionwithprocessmanagement.–Processcreationanddeletion.–processsuspensionandresumption.–Provisionofmechanismsfor:•processsynchronization•processcommunicationMain-MemoryManagement•Memoryisalargearrayofwordsorbyteswhichisarepositoryofquic

6、klyaccessibledatasharedbytheCPUandI/Odevices.•Theoperatingsystemisresponsibleforthefollowingactivities:–Keeptrackofwhichpartsofmemoryarecurrentlybeingusedandbywhom.–Decidewhichprocessestoloadwhenmemoryspacebecomesavailable.–Allocateanddeallocatememoryspac

7、easneeded.FileManagement•Afileisacollectionofrelatedinformationdefinedbyitscreator.•Theoperatingsystemisresponsibleforthefollowingactivities:–Filecreationanddeletion.–Directorycreationanddeletion.–Supportofprimitivesformanipulatingfilesanddirectories.–Map

8、pingfilesontosecondarystorage.–Filebackuponstable(nonvolatile)storagemedia.I/OSystemManagement•TheI/Osystemconsistsof:–Abuffer-cachingsystem–Ageneraldevice-driverinterface–DriversforspecifichardwaredevicesSecondary-