计算机操作系统--Operating-System-OverviewPPT课件

Chapter1OperatingSystemOverview,Contents,OperatingSystemObjectivesandFunctionsTheEvolutionofOperatingSystemMajorAchievementsCharacteristicsofModernOSExamples（NT、UNIX）,1.1ObjectivesandFunctions(p45),1.1.1Overview1.1.2TheOperatingSystemasaUser/ComputerInterface1.1.3TheOperatingSystemasResourceManager1.1.4EaseofEvolutionofanOperatingSystem,Anoperatingsystemisaprogramthatmanagesthecomputer,controlstheexecutionofapplicationprogramsandactsasaninterface(接口)betweentheuserofacomputerandthecomputerhardware.ObjectivesConvenience（方便）Efficiency（有效）Abilitytoevolve（易扩展）,1.1.1Overview,1.1.2OSasaUser/ComputerInterface(I),Figure2.1LayersandViewsofaComputerSystem,ComputerHardware,OperatingSystem,Utilities(Compiler,Database),ApplicationsPrograms,OperatingSystemDesigner,Programmers,EndUser,Theoperatingsystemmasks（隐藏）thedetailsofthehardwarefromtheprogrammer，andprovidestheprogrammerwithaconvenientinterfaceforusingthesystem.ThetypesofsysteminterfaceCommandinterface:systemcommand(internal、external)Graphicsinterface:windowsProgrammerinterface:systemcall,c-lib,OSasaUser/ComputerInterface(II),ServicesoftheOperatingSystem(I),ProgramcreationSuchas:fork(unix)、CreateProcess(win)ProgramexecutionSuchas:execl,execpAccesstoI/OdevicesSuchas:read/writeControlledaccesstofilesSuchas:read/write,ServicesoftheOperatingSystem(II),SystemaccessProvideprotectionandauthorizedErrordetectionandresponseSuchas:errorAccounting,1.1.3OSasResourceManager(I)（p47）,TypesofResource:CPU、Memory、DevicesCPU:chapter.9.10Memory:chapter7.8I/ODevices:chapter11.12,OSasResourceManager(II),AsacontrolmechanismisunusualintworespectsTheOSfunctionsinthesamewayasordinarycomputersoftware;thatis,itisaprogramexecutedbytheprocessor.TheOSfrequentlyrelinquishescontrol(释放控制)andmustdependontheprocessortoallowittoregaincontrol（获取控制）.,OSasResourceManager(IIIFigure2.2),ManagementofCPUManagementofI/ODeviceManagementofMemoryManagementofFilesConcept:Kernel、Nucleus(内核):Alwaysinmainmemory,containsthemost-frequently-usedfunctions,1.1.4EaseofEvolution（p49）,ReasonsforevolutionhardwareupgradesExp:supportpagingnewservicesfixesImplementssoftwareengineering:modules、layer、objectdesign,1.2TheEvolutionofOperatingSystems,1.2.1SerialProcessing1.2.2SimpleBatchSystems1.2.3Multiprogrammed（多道）BatchSystems1.2.4Time-SharingSystems,1.2.1SerialProcessing(p50串行处理),ExampleInputCalculatePrintProblemsScheduling:TheestimatedtimeisnotaccurateSetuptime:Betweenthesetupprocedure,ifanerroroccurred,thenmustgobacktothebeginningofthesetupsequenceContradictionbetweenhumanandmachine,1.2.2SimpleBatchSystem,Objectives：SolutioncontradictionbetweenhumanandmachineUsersubmitsthejoboncardsortapetoacomputeroperator(useJCL（jobcontrollanguage)Implement:Monitor,FromthePointofViewoftheMonitor(p51),MonitorisresponsiblefortherunningofeveryjobControlsaretransferredbetweenmonitorandotheruserprograms,Interruptprocessing,DeviceDrivers,JobSequencing,ControlLanguageInterpreter,UserProgramArea,monitor,Memorylayoutforaresident(驻留)monitor,FromthePointofViewoftheProcessor,WhenCPUrunscommandofmonitor,themonitorgainsthecontrol.WhenCPUrunscommandofuserprogram,theuserprogramgainsthecontrol.Transferthecontrol:Firstmonitorgainsthecontrol,whenuserprogramloadin,itgainsthecontrol,whentheuserprogramfinishorerror,themonitorregains（重获）thecontrol.,JCL(JobControlLanguage),$JOB/begin$FTN/usingFortrancompileandlinkFortran/instructions$LOAD/loadinrunablemodules$RUN/running.$END/finishdothejob,OtherHardwareFeatureDesirable(p53),Memoryprotection（内存保护）:Userspaceandsystemspaceareindependent.E.g.Hardwarecandetectoutsideaccessingerror.Timerinterrupt（时钟中断）:Whenthetimerexpires,aninterruptoccurs.Privilegedinstructions（特权指令）:Canbeexecutedonlybythemonitor.Interrupts:ImprovementefficiencyEasyforrelinquishing（释放）andregainingcontrol,1.2.3MultiprogrammedBatchSystems,Readonerecord0.0015secondsExecute100instructions0.0001secondsWriteonerecord0.0015secondsTOTAL0.0031secondsPercentCPUUtilization=0.0001/0.0031=3.2%Figure2.4SystemUtilizationExample,Uniprogramming（单道）haslowefficiency（效率）:CPU-I/Ocontradiction,Multiprogramming/Multitasking,Therearemanyuserprogramsinthememory.HardwareneedforMultiprogramming.InterruptionForexample:p55Fig2.5,ExampleofMultiprogramming,256kavailablememoryNotes:notconsidertheresourcecompetition,Table2.1SampleProgramExecutionAttributes,Analysis,Analysis,SingleProcessoruse5/(5+15+10)=17%Memoryuse=(50*5+100*15+80*10)/256/30=33%Diskuse=10/30=33%Printeruse10/30=33%Totaltime5+15+1030Throughput6job/hourMeanresponsetime（5+20+30）/3=18,Analysis,MultiprogrammingProcessoruse5/15=33%Memoryuse=(50+100+80)*5+(100+80)*5+100*5/256/15=65%Diskuse=10/15=67%Printeruse10/15=67%Totaltime15Throughout12job/hourMeanresponsetime（5+10+15）/3=10,Sophisticated(复杂性)ofMultiprogramming(p57),MemorymanagementSchedulingAlgorithm（算法）:Theprocessor（处理器）mustdecidewhichonetorun.,1.2.4Time-SharingSystems,Multipleuserssimultaneously（同时）accessthesystemthroughterminals(终端)Concepts:timeslice（时间片）:qusernum（用户数）:nresponsetime（响应时间）:tt=nqMode:multi-terminals、multi-windows,BatchMultiprogrammingvsTimerSharing,ReducingtheSwappingLoadsbyPartialSwapping（p59）,Reducingthespendingforaccessingdisk,1.3MajorAchievements（p60）,1.3.1Processes(进程)1.3.2Memorymanagement1.3.3Informationprotectionandsecurity1.3.4Schedulingandresourcemanagement1.3.5Systemstructure,1.3.1Processes,AprograminexecutionTheanimatedspirit（活动精灵）ofaprogramTheentity（实体）thatcanbeassigned（分派）toandexecutedonaprocessorThreemajortypesofcomputersystemMultiprogrammingbatchoperationTimesharingReal-timetransaction（处理）systems,ErrorsMayHappeninMultiprogramming,Impropersynchronization（同步）:Signalsbeinglostorduplicate（重复）signalsbeingreceived.Failedmutualexclusion(失败的互斥)Nondeterminate（不确定）programoperation:TheresultisnotuniqueDeadlocks（死锁）Tosolutetheseproblems,introduceprocessconcept,Processentity(实体),AnexecutableprogramTheassociateddataneededbytheprogramTheexecutioncontext(上下文)oftheprogram,ProcessImageandProcessSwitch（切换）(p63),1.3.2MemoryManagement,Processisolation（隔离）AutomaticallocationandmanagementSupportofmodular（模块化）programmingVirtuallymemoryLong-termstorageProtectionandaccesscontrol（访问控制）,Fig2.10TwoViewsofaStorageSystem,VirtualProcessor,RealProcessor,Mapper(AddressTranslate),MainMemory,AuxiliaryMemory,VirtualMemory,Files,(a)UsersView,(b)OperatingSystemDesignersView,VirtualAddress,MemoryAddress,Swapping,Read,Write,Copy,Long-termStore,1.3.3InformationProtectionandSecurity,Accesscontrol:forvariousresourcesinthesystemInformationflowcontrol（信息流控）:toguaranteethedatatosendtodestinationCertification（认证）,1.3.4SchedulingandResourceManagement（p66）,ThreefactorsmustbeconsiderFairnessDifferentialresponsiveness(区分服务):e.g.IfaprocessiswaitingfortheuseofanI/Odevice,theoperatingsystemmaywishtoschedulethatprocessforexecutionassoonaspossibleinordertofreeupthedeviceforlaterdemandsfromotherprocesses.Efficiency:Maximizethroughput(吞吐量),minimizeresponsetime,accommodate（容纳）asmanyusersaspossible,ShorttermqueueAlgorithmusedtouse:roundrobin（轮转）LongtermqueueAlgorithmusedtouse:FIFOInterrupthandler:themethodforgetthecontrolServicecallhandler（系统服务处理）:theentrypointintotheoperatingsystem,SomeConcepts（p67）,Fig2.11KeyelementsofanOperatingSystemforMultiprogramming,ServiceCallHandler,InterruptHandler,Long-termQueue,Short-termQueue,Short-TermScheduler,I/Oqueue,OS,Modules（模块化）structure:onlysuitableforsmallsystem;forcomplexsystem,difficultfordebugHierarchical（层）structureLevelnprovidesserviceforleveln+1,SystemStructure(p68系统结构),Hierarchy(Table2.4),LevelNameObjectsExampleOperations13ShellUserprogrammingStatementsinshelllanguageenvironment12UserprocessesUserprocessesQuit,kill,suspend,resume11DirectoriesDirectoriesCreate,destroy,attach,detach,search,list10DevicesExternaldevicesOpen,close,asprinter,displaysread,writeandkeyboards9FilesystemFilesCreate,destroy,open,closeread,write8CommunicationsPipesCreate,destroy,open,close,read,write,Hierarchy,LevelNameObjectsExampleOperations7VirtualMemorySegments,pagesRead,write,fetch6LocalsecondaryBlocksofdata,deviceRead,write,allocate,freestorechannels5PrimitiveprocessesPrimitiveprocess,Suspend,resume,wait,semaphores,readysignallist,Hierarchy(Hardware),LevelNameObjectsExampleOperations4InterruptsInterrupt-handlingInvoke,mask,unmask,retryprogramsProceduresProcedures,callstack,Markstack,call,returndisplay2InstructionSetEvaluationstack,micro-Load,store,add,subtractprograminterpreter,branchscalarandarraydata1ElectroniccircuitsRegisters,gates,buses,Clear,transfer,activate,plement,1.4.1Microkernelarchitecture（微内核结构）1.4.2Multithreading（多线程）1.4.3Symmetricmultiprocess（对称多处理）1.4.4Distributedoperatingsystems（分布式系统）1.4.5Object-orienteddesign（对象设计）,1.4CharacteristicsofModernOS(p71),Assignsonlyafewessential（必要的）functionstothekernel,includingaddressspaces,interprocesscommunication(IPC)（进程间通信）,andbasicscheduling.Simplifiesimplementation,providesflexibility（伸缩性）andwellsuitedtoadistributedenvironment.,1.4.1Microkernel,1.4.2Multithreading,