OperatingSystemConcepts操作系統(tǒng)原理OperatingSystemConcepts課程概況(1/4)教學(xué)內(nèi)容教學(xué)要求Introduction掌握操作系統(tǒng)的一般情況,了解本課程的學(xué)習(xí)方法OperatingsystemStructures介紹操作系統(tǒng)的組成使學(xué)生樹(shù)立操作系統(tǒng)的整體概念ProcessManagement操作系統(tǒng)的最重要的部分,要求學(xué)生牢固掌握進(jìn)程概念,能夠借助進(jìn)程概念編寫(xiě)并發(fā)程序Threads要求學(xué)生掌握創(chuàng)建和管理線程的方法熟練使用多線程技術(shù)編程CPUScheduling要求學(xué)生理解并能編寫(xiě)一個(gè)進(jìn)程調(diào)度的程序ProcessSynchronization要求學(xué)生理解同步概念,掌握同步的編程方法Deadlocks要求學(xué)生理解死鎖現(xiàn)象,了解預(yù)防、避免、檢測(cè)、解除死鎖的方法OperatingSystemConcepts課程概況(2/4)教學(xué)內(nèi)容教學(xué)要求MemoryManagement掌握固定分區(qū),可變分區(qū),段式,頁(yè)式存儲(chǔ)管理原理與算法VirtualMemory虛擬存儲(chǔ)是操作系統(tǒng)另一個(gè)重要概念。要求學(xué)生正確的理解虛存的概念熟練掌握請(qǐng)求頁(yè)式的地址變換過(guò)程以及常用的頁(yè)面置換算法FileSystems掌握文件系統(tǒng)的基本概念，熟練使用文件系統(tǒng)的操作方法I/OSystems掌握I/O系統(tǒng)的基本概念，理解設(shè)備驅(qū)動(dòng)程序。弄清從用戶請(qǐng)求到設(shè)備完成用戶請(qǐng)求的全過(guò)程Mass-StorageStructure了解幾種磁盤(pán)調(diào)度算法OperatingSystemConcepts課程概況(3/4)學(xué)時(shí)：64學(xué)時(shí)教材操作系統(tǒng)概念（第七版影印版）西爾伯莎茨編著高教社2007OperatingSystemConcepts課程概況(4/4)考核方式閉卷考試成績(jī)?cè)u(píng)定:由下述三部分組成期末考試成績(jī)期中考試成績(jī)平時(shí)成績(jī)（作業(yè)、出勤等）OfficeHours:Monday:14:00~17:00(E-maildiscussionsarewelcome)Chapter1IntroductionWhatOperatingSystemsDoComputer-SystemOrganizationComputer-SystemArchitectureOperating-SystemStructureOperating-SystemOperationsProcessManagementMemoryManagementStorageManagementProtectionandSecurityDistributedSystemsSpecial-PurposeSystemsComputingEnvironmentsOperatingSystemConceptsChapter1:Introduction(6thEd.)WhatisanOperatingSystem?MainframeSystemsDesktopSystemsMultiprocessorSystemsDistributedSystemsClusteredSystemReal-TimeSystemsHandheldSystemsComputingEnvironmentsOperatingSystemConceptsChapter2:Computer-SystemStructures(6thEd.)ComputerSystemOperationI/OStructureStorageStructureStorageHierarchyHardwareProtectionNetworkStructureOperatingSystemConceptsTwoShortStoriesaboutOSStoryOne

OperatingSystemConcepts1988,

進(jìn)入赫爾辛基大學(xué)計(jì)算機(jī)系1989，進(jìn)入芬蘭陸軍，服11個(gè)月的兵役，主要服務(wù)于計(jì)算機(jī)部門(mén)1990，退伍後回到大學(xué)，開(kāi)始接觸Unix。根據(jù)安德魯·斯圖爾特·塔能鮑姆所著的教科書(shū)及minix源碼，打造了自己的操作系統(tǒng)1991，在網(wǎng)絡(luò)上發(fā)布Linux內(nèi)核OperatingSystemConceptsLinusTorvalds

StoryOne

SelectedQuotesfromLinusTorvaldsOperatingSystemConcepts"MynameisLinusTorvaldsandIamyourgod."——在1998Linux大會(huì)上的自我介紹StoryOne

SelectedQuotesfromLinusTorvaldsOperatingSystemConcepts"那年夏天我做了兩件事。第一件事是什么都沒(méi)做。第二件事是讀完了719頁(yè)的《操作系統(tǒng)：設(shè)計(jì)和執(zhí)行》。那本紅色的簡(jiǎn)裝本教科書(shū)差不多等于睡在了我的床上。"——關(guān)于暑假StoryOne

OperatingSystemConcepts"Linux不是靠犧牲寶貴的睡眠時(shí)間換來(lái)的。事實(shí)上，如果你想聽(tīng)真話，那我就要說(shuō)，我更喜歡睡覺(jué)。"——關(guān)于超時(shí)工作SelectedQuotesfromLinusTorvaldsStoryOne

OperatingSystemConcepts"尋找樂(lè)趣，做一些有趣的事情，增加財(cái)富和提高名聲。"——關(guān)于生活哲學(xué)SelectedQuotesfromLinusTorvaldsStoryOne

OperatingSystemConceptsStoryTwo

AMS在奮進(jìn)號(hào)艙內(nèi)2011年5月19日5:15安裝完畢，9:35開(kāi)始接收數(shù)據(jù)77AMSPayloadandOperationControlCenterGeneva,SwitzerlandAMSDataFlow約翰遜航天中心（北航）SEUSupercomputingCenterInfiniband

cablesOperatingSystemConceptsFCcablesOperatingSystemConceptsOperatingSystemConceptsComputerSystemComponents1. Hardware–providesbasiccomputingresources(CPU,memory,I/Odevices).2. Operatingsystem–controlsandcoordinatestheuseofthehardwareamongthevariousapplicationprogramsforthevarioususers.3. Applicationsprograms–(compilers,databasesystems,videogames,businessprograms)areusedtosolveuserproblems.4. Users(people,machines,othercomputers).OperatingSystemConceptsAbstractViewofSystemComponentsOperatingSystemConceptsUserViewPCUsers:anoperatingsystemisaprogramthatprovidesaneasy-to-useinterfaceforusingthehardwareWorkstationUsers:anoperatingsystemisaprogramdesignedtocompromisebetweenindividualusabilityandresourceutilizationExperienceasaremoteuser?OperatingSystemConceptsSystemView(1/2)AResourceallocator:theoperatingsystemallocatesandreclaimsthesystemhardwareresourcestoandfromuserprogramsAControlProgram:theoperatingsystemcontrolstheexecutionofuserprogramstopreventerrorsandimproperuseofthecomputerOperatingSystemConceptsSystemView(2/2)Thereisno

universaldefinitionofwhatisanoperatingsystem.Acommondefinitionisthattheoperatingsystemistheoneprogramrunningatalltimesonthecomputer(i.e.,thekernel).AllotherprogramsareapplicationprogramsOperatingSystemConceptsTheGoalsofanOperatingSystemPrimaryGoal:efficient

operationofthecomputersystem.

Insomesystems,itisconvenience.

Inthepast,efficiencyisfarmoreimportantthanconvenience.OperatingSystemConceptsWhatisanOperatingSystem?Aprogramthatactsasanintermediarybetweentheapplicationprogramsandthecomputerhardware.Executeuserprogramsandmakesolvinguserproblemseasier.Makethecomputersystemconvenienttouse.Usethecomputerhardwareinanefficientmanner.Fromthecomputer’spointofview:Aresourceallocator,acontrolprogram,akernelOperatingSystemConceptsDesktopSystems(1/2)Personalcomputers–computersystemdedicatedtoasingleuser.I/Odevices–keyboards,mouse,displayscreens,smallprinters.Userconvenienceandresponsiveness.OperatingSystemConceptsDesktopSystems(2/2)CanadopttechnologydevelopedforlargeroperatingsystemindividualshavesoleuseofcomputeranddonotneedadvancedCPUutilizationofprotectionfeatures.Mayrunseveraldifferenttypesofoperatingsystems(Windows,MacOS,UNIX,Linux)OperatingSystemConceptsParallelSystemsMultiprocessorsystemswithmorethanoneCPUinclosecommunication.Tightlycoupledsystem–processorssharememoryandaclock;communicationusuallytakesplacethroughthesharedmemory.OperatingSystemConceptsParallelSystems(Cont.)Advantagesofparallelsystem:Increasedthroughput:GetsmorejobsdoneEconomyofscale:Becauseofresourcesharing,multiprocessorsystemsischeaperthanmultiplesingleprocessorsystems

Increasedreliability:thefailureofoneprocessorwillnothaltthewholesystemgracefuldegradationFault-tolerantsystemsOperatingSystemConceptsParallelSystems(Cont.)Symmetricmultiprocessing(SMP)Eachprocessorrunsanidenticalcopyoftheoperatingsystem.Manyprocessescanrunatoncewithoutperformancedeterioration.MustcarefullycontrolI/OtoensurethatthedatareachtheappropriateprocessorMayresultininefficienciesMostmodernoperatingsystemssupportSMPOperatingSystemConceptsSymmetricMultiprocessingArchitectureOperatingSystemConceptsParallelSystems(Cont.)AsymmetricmultiprocessingEachprocessorisassignedaspecifictask.Amasterprocessorcontrolsthesystem.Theotherprocessorseitherlooktothemasterforinstructionsorhavepredefinedtasks.Thus,thisdefinesamaster-slaverelationshipmasterprocessorschedulesandallocatedworktoslaveprocessors.MorecommoninextremelylargesystemsOperatingSystemConceptsDistributedSystemsDistributethecomputationamongseveralphysicalprocessors.Looselycoupledsystem–eachprocessorhasitsownlocalmemory;processorscommunicatewithoneanotherthroughvariouscommunicationslines,suchashigh-speedbusesortelephonelines.OperatingSystemConceptsDistributedSystems(cont)Adistributedsystemisacollectionofphysicallyseparate,possibleheterogeneouscomputersystemsthatarenetworked

toprovidetheuserswithaccesstothevariousresourcesthatthesystemmaintainsAdvantagesofdistributedsystems.ResourcesSharingComputationspeedup–loadsharingReliabilityCommunicationsOperatingSystemConceptsDistributedSystems(cont)Requiresnetworkinginfrastructure.Localareanetworks(LAN)orWideareanetworks(WAN)Maybeeitherclient-serverorpeer-to-peersystems.OperatingSystemConceptsGeneralStructureofClient-ServerOperatingSystemConceptsClusteredSystemsAclusteredsystemhastwoormoreindividualsystemssharedstorageandcloselylinkedviaLANnetworkingThekeyofclusteredsystemishighavailability.AsymmetricClustering:Onemachineisinhot-standbymodewhileothersarerunningapplications.Thehot-standbymachine(i.e.,doesnothingbut)monitorsothermachinesandbecomesactiveifoneserverfails.SymmetricClustering:Twoormorehostsarerunningapplicationsandmonitoreachother.ThisismoreefficientasitusesallavailablehardwareDemoLinuxBasiccommands:ls,mv,vi,cp,scp,hostname,ssh，xserver….gccClusterJobscheduler:LoadSharingFacility(LSF)BsubexampleFileSystem:GPFSOperatingSystemConceptsHomework1OperatingSystemConceptsReal-TimeSystemsOftenusedasacontroldeviceinadedicatedapplicationsuchascontrollingscientificexperiments,medicalimagingsystems,industrialcontrolsystems,andsomedisplaysystems.OperatingSystemConceptsReal-TimeSystems(Cont.)Areal-timeoperatingsystemhaswell-defined,fixedtimeconstraints.Processingmust

bedonewithinthedefinedconstraints,orthesystemwillfail.Real-Timesystemsmaybeeitherhard

orsoftreal-time.HardReal-TimeSystemsguaranteethatcriticaltasksbecompletedontime.SoftReal-TimeSystemsprioritizecriticaltasks.Thatis,acriticaltaskgetpriorityoverothertasks,andretainsthatpriorityuntilitcompletes.Embeddedsystemsalmostalwaysrunreal-timeoperatingsystemsOperatingSystemConceptsHandheldSystemsPersonalDigitalAssistants(PDAs)CellulartelephonesIssues:LimitedmemorySlowprocessorsSmalldisplayscreens.OperatingSystemConceptsMultiprogrammedBatchSystemsSeveraljobsarekeptinmainmemoryatthesametime,andtheCPUismultiplexedamongthem.KeepsservaljobsinmemorysimultaneouslyPicksandbeginstoexecuteoneIfthatjobneedstowait,CPUisswitchedtoanotheroneIt’sthefirstinstancewheretheoperatingsystemmustmakedecisionsfortheusersOperatingSystemConceptsOSFeaturesNeededforMultiprogrammingI/Oroutinesuppliedbythesystem.Memorymanagement–thesystemmustallocatethememorytoseveraljobs.CPUscheduling–thesystemmustchooseamongseveraljobsreadytorun.Allocationofdevices.Jobscheduling–thesystemmustchooseamongjobsreadytobebroughtintomemoryOperatingSystemConceptsAdvantagesanddisadvantagesofmultiprogramming:CPU利用率大大提高用戶無(wú)控制權(quán)，無(wú)交互性，延遲大引入多道程序設(shè)計(jì)技術(shù)的根本目的：

提高CPU的利用率，充分發(fā)揮并行性，

這包括：程序之間；設(shè)備之間；設(shè)備與CPU之間均并行工作。OperatingSystemConcepts例：有兩道程序A、B，按下圖以多道程序方式運(yùn)行，要求在右圖畫(huà)出它們的運(yùn)行軌跡，并計(jì)算在60ms內(nèi)，CPU的利用率，假設(shè)起始時(shí)首先運(yùn)行B，并允許忽略監(jiān)督程序切換A、B的時(shí)間。OperatingSystemConcepts運(yùn)行15msI/O20ms運(yùn)行10msI/O10msABBAI/OI/O10ms60mstBA請(qǐng)畫(huà)個(gè)示意圖。OperatingSystemConcepts解：BAI/OI/O1060t20304050253545若在單道程序系統(tǒng)中，CPU的利用率是多少？OperatingSystemConcepts為了說(shuō)明多道程序的優(yōu)點(diǎn)，不妨參考RTurner提出的例子：某計(jì)算機(jī)系統(tǒng)，有256KB的主存(不包含操作系統(tǒng))，一個(gè)磁盤(pán)，一個(gè)終端和一臺(tái)打印機(jī)。同時(shí)提交的三個(gè)作業(yè)分別命名為JOB1、JOB2、JOB3。各作業(yè)運(yùn)行時(shí)間分別為5min、15min和10min。它們對(duì)資源的使用情況如下表所示：OperatingSystemConcepts作業(yè)名作業(yè)類型所需主存/KB所需磁盤(pán)所需終端所需打印機(jī)運(yùn)行時(shí)間/minJOB1CPU型50不用不用不用5JOB2I/O型100不用需要不用15JOB3I/O型80需要不用需要10三個(gè)作業(yè)的執(zhí)行要求OperatingSystemConcepts假定JOB1主要使用CPU處理數(shù)據(jù)，JOB2主要使用終端進(jìn)行作業(yè)的輸入，JOB3運(yùn)行時(shí)主要使用磁盤(pán)和打印機(jī)，后兩作業(yè)都只需要較少的CPU時(shí)間。對(duì)于簡(jiǎn)單批處理情況，這些作業(yè)將按順序執(zhí)行。JOB1運(yùn)行5min完成，JOB2在等待5min后，運(yùn)行15min完成，JOB3在等待20min后開(kāi)始執(zhí)行。三個(gè)作業(yè)全部完成需要30min(這三個(gè)作業(yè)是一批)。OperatingSystemConcepts采用多道程序設(shè)計(jì)技術(shù)，可讓這三個(gè)作業(yè)并行運(yùn)行。由于它們運(yùn)行中幾乎不同時(shí)使用同一資源，所以三個(gè)作業(yè)可同時(shí)運(yùn)行。JOB1在進(jìn)行數(shù)據(jù)處理的同時(shí)，JOB2在終端上進(jìn)行作業(yè)輸入，JOB3在使用磁盤(pán)和打印機(jī)。因此，JOB1只需5min完成，JOB2需15min完成，JOB3需10min完成。這樣三個(gè)作業(yè)全部完成的時(shí)間只需15min，顯然系統(tǒng)處理效率明顯提高。OperatingSystemConceptsTime-SharingSystems–InteractiveComputing（1/2）Interactivecomputersystemprovidesdirectcommunicationbetwe