中山大学软件学院操作系统概念课件——ch1.ppt

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1、Chapter1:IntroductionChapter1:IntroductionWhatOperatingSystemsDoComputer-SystemOrganizationComputer-SystemArchitectureOperating-SystemStructureOperating-SystemOperationsProcessManagementMemoryManagementStorageManagementProtectionandSecurityDistributedSystemsSpecial-PurposeSystemsCo

2、mputingEnvironmentsOpen-SourceOperatingSystemsObjectivesToprovideagrandtourofthemajoroperatingsystemscomponentsToprovidecoverageofbasiccomputersystemorganizationWhatisanOperatingSystem?AprogramthatactsasanintermediarybetweenauserofacomputerandthecomputerhardwareOperatingsystemgoals

3、:ExecuteuserprogramsandmakesolvinguserproblemseasierMakethecomputersystemconvenienttouseUsethecomputerhardwareinanefficientmannerComputerSystemStructureComputersystemcanbedividedintofourcomponents:Hardware–providesbasiccomputingresourcesCPU,memory,I/OdevicesOperatingsystemControlsa

4、ndcoordinatesuseofhardwareamongvariousapplicationsandusersApplicationprograms–definethewaysinwhichthesystemresourcesareusedtosolvethecomputingproblemsoftheusersWordprocessors,compilers,webbrowsers,databasesystems,videogamesUsersPeople,machines,othercomputersFourComponentsofaCompute

5、rSystemWhatOperatingSystemsDoDependsonthepointofviewUserswantconvenience,easeofuseDon’tcareaboutresourceutilizationButsharedcomputersuchasmainframeorminicomputermustkeepallusershappyUsersofdedicatesystemssuchasworkstationshavededicatedresourcesbutfrequentlyusesharedresourcesfromser

6、versHandheldcomputersareresourcepoor,optimizedforusabilityandbatterylifeSomecomputershavelittleornouserinterface,suchasembeddedcomputersindevicesandautomobilesOperatingSystemDefinitionOSisaresourceallocatorManagesallresourcesDecidesbetweenconflictingrequestsforefficientandfairresou

7、rceuseOSisacontrolprogramControlsexecutionofprogramstopreventerrorsandimproperuseofthecomputerOperatingSystemDefinition(Cont.)Nouniversallyaccepteddefinition“Everythingavendorshipswhenyouorderanoperatingsystem”isgoodapproximationButvarieswildly“Theoneprogramrunningatalltimesontheco

8、mputer”isthekernel.Everyth