计算机系统结构2英文课件

Chapter3

Operating-SystemStructuresSystemComponentsOperatingSystemServicesSystemCallsSystemProgramsSystemStructureVirtualMachinesSystemDesignandImplementationChapter3

Operating-SystemStructuresSystemComponentsOperatingSystemServicesSystemCallsSystemProgramsSystemStructureVirtualMachinesSystemDesignandImplementationCommonSystemComponentsProcessManagementMainMemoryManagementSecondary-StorageManagementI/OSystemManagementProtectionSystemNetworkingCommand-InterpreterSystemMain-MemoryManagementMemoryisalargearrayofwordsorbytes,eachwithitsownaddress.Itisarepository

ofquicklyaccessibledatasharedbytheCPUandI/Odevices.Mainmemoryisavolatile

storagedevice.Itlosesitscontentsinthecaseofsystemfailure.Theoperatingsystemisresponsibleforthefollowingactivitiesinconnectionswithmemorymanagement:Keeptrackofwhichpartsofmemoryarecurrentlybeingusedandbywhom.Decidewhichprocessestoloadwhenmemoryspacebecomesavailable.Allocateanddeallocatememoryspaceasneeded.Secondary-StorageManagementSincemainmemory(primarystorage)isvolatileandtoosmalltoaccommodatealldataandprogramspermanently,thecomputersystemmustprovidesecondarystoragetobackupmainmemory.Mostmoderncomputersystemsusedisksastheprincipleon-linestoragemedium,forbothprogramsanddata.TheoperatingsystemisresponsibleforthefollowingactivitiesinconnectionwithdiskmanagementFreespacemanagementStorageallocationDiskschedulingI/OSystemManagementTheI/Osystemconsistsof:Abuffer-cachingsystemAgeneraldevice-driverinterfaceDriversforspecifichardwaredevicesProtectionSystemProtectionreferstoamechanismforcontrollingaccessbyprograms,processes,oruserstobothsystemanduserresources.Tvideameansofenforcement.

Networking(DistributedSystems)Adistributedsystemisacollectionprocessorsthatdonotsharememoryoraclock.Eachprocessorhasitsownlocalmemory.Theprocessorsinthesystemareconnectedthroughacommunicationnetwork.Adistributedsystemprovidesuseraccesstovarioussystemresources.Accesstoasharedresourceallows:Computationspeed-up加速运算Increaseddataavailability提高数据利用性Enhancedreliability增强可靠性Command-InterpreterSystemManycommandsaregiventotheoperatingsystembycontrolstatementswhichdealwith:processcreationandmanagementI/Ohandlingsecondary-storagemanagementmain-memorymanagementaccessprotectionnetworkingChapter3

Operating-SystemStructuresSystemComponentsOperatingSystemServicesSystemCallsSystemProgramsSystemStructureVirtualMachinesSystemDesignandImplementationOperatingSystemServicesProgramexecution

–systemcapabilitytoloadaprogramintomemoryandtorunit.I/Ooperations

–sinceuserprogramscannotexecuteI/Ooperationsdirectly,theoperatingsystemmustprovidesomemeanstoperformI/O.manipulation

–programcapabilitytoread,write,create,anddeletefiles.Communications

–exchangeofinformationbetweenprocessesexecutingeitheronthesamecomputerorondifferentsystemstiedtogetherbyanetwork.Implementedviasharedmemoryormessagepassing.Errordetection

–ensurecorrectcomputingbydetectingerrorsintheCPUandmemoryhardware,inI/Odevices,orinuserprograms.AdditionalOperatingSystemFunctionsAdditionalfunctionsexistnotforhelpingtheuser,butratherforensuringefficientsystemoperations.Resourceallocation

–allocatingresourcestomultipleusersormultiplejobsrunningatthesametime.Accounting

–keeptrackofandrecordwhichusersusehowmuchandwhatkindsofcomputerresourcesforaccountbillingorforaccumulatingusagestatistics.Protection

–ensuringthatallaccesstosystemresourcesiscontrolled.PassingofParametersAsATable

表格方式的参数传递Chapter3

Operating-SystemStructuresSystemComponentsOperatingSystemServicesSystemCallsSystemProgramsSystemStructureVirtualMachinesSystemDesignandImplementationSystemCalls(Cont.)ProcesscontrolDevicemanagementInformationmaintenanceCommunicationsMS-DOSExecutionAtSystemStart-up系统启动RunningaProgram运行程序UNIXRunningMultipleProgramsSystemCall

——createfile,deletefileopen,closeread,write,repositionget,setSystemCall

——informationmanagementgettimeordate,settimeordategetsystemdata,setsystemdatagetprocess,file,ordeviceattributessetprocess,file,ordeviceattributesSystemCall

——communicationscreate,deletecommunicationconnectionsend,receivemessagestransferstatusinformationattachordetachremotedevicesSystemProgramsSystemprogramsprovideaconvenientenvironmentforprogramdevelopmentandexecution.Theycanbedividedinto:StatusinformationProgramminglanguagesupportProgramloadingandexecutionCommunicationsApplicationprogramsChapter3

Operating-SystemStructuresSystemComponentsOperatingSystemServicesSystemCallsSystemProgramsSystemStructureVirtualMachinesSystemDesignandImplementationSystemStructure–LayeredApproachTheoperatingsystemisdividedintoanumberoflayers(levels),eachbuiltontopoflowerlayers.Thebottomlayer(layer0),isthehardware;thehighest(layerN)istheuserinterface.Withmodularity,layersareselectedsuchthateachusesfunctions(operations)andservicesofonlylower-levellayers.AnOperatingSystemLayerLayeredStructureoftheTHEOSAlayereddesignwasfirstusedinTHEoperatingsystem.

Itssixlayersareasfollows:MicrokernelsWindowsNTClient-ServerStructureChapter3

Operating-SystemStructuresSystemComponentsOperatingSystemServicesSystemCallsSystemProgramsSystemStructureVirtualMachinesSystemDesignandImplementationVirtualMachinesAvirtualmachinetakesthelayeredapproachtoitslogicalconclusion.Ittreatshardwareandtheoperatingsystemkernelasthoughtheywereallhardware.虚拟机是层次化的逻辑结果Avirtualmachineprovidesaninterfaceidenticaltotheunderlyingbarehardware.Theoperatingsystemcreatestheillusionofmultipleprocesses,eachexecutingonitsownprocessorwithitsown(virtual)memory.操作系统创建了多个进程，每个进程在其处理器和（虚拟）内存执行VirtualMachines(Cont.)Theresourcesofthephysicalcomputeraresharedtocreatethevirtualmachines.CPUschedulingcancreatetheappearancethatusershavetheirownprocessor.Spoolingandacanprovidevirtualcardreadersandvirtuallineprinters.Anormalusertime-sharingterminalservesasthevirtualmachineoperator’sconsole.

普通用户终端成为虚拟机操作员的控制台SystemModelsNon-virtualMachineVirtualMachineAdvantages/DisadvantagesofVirtualMachinesThevirtual-machineconceptprovidescompleteprotectionofsystemresourcessinceeachvirtualmachineisisolatedfromallothervirtualmachines.Avirtual-machinesystemisaperfectvehicleforoperating-systemsresearchanddevelopment.Systemdevelopmentisdoneonthevirtualmachine,insteadofonaphysicalmachineandsodoesnotdisruptnormalsystemoperation.Thevirtualmachineconceptisdifficulttoimplementduetotheeffortrequiredtoprovideanexact

duplicatetotheunderlyingmachine.TheJavaVirtualMachineJava.classCrossPlatforms

跨平台的Java.class文件JavaDevelopmentEnvironmentChapter3

Operating-SystemStructuresSystemComponentsOperatingSystemServicesSystemCallsSystemProgramsSystemStructureVirtualMachinesSystemDesignandImplementationSystemDesignGoalsUsergoals–operatingsystem