操作系统原理英文版课件：Chapter 1 Introduction

OperatingSystemConcepts操作系统原理OperatingSystemConcepts课程概况(1/4)教学内容教学要求Introduction掌握操作系统的一般情况,了解本课程的学习方法OperatingsystemStructures介绍操作系统的组成使学生树立操作系统的整体概念ProcessManagement操作系统的最重要的部分,要求学生牢固掌握进程概念,能够借助进程概念编写并发程序Threads要求学生掌握创建和管理线程的方法熟练使用多线程技术编程CPUScheduling要求学生理解并能编写一个进程调度的程序ProcessSynchronization要求学生理解同步概念,掌握同步的编程方法Deadlocks要求学生理解死锁现象,了解预防、避免、检测、解除死锁的方法OperatingSystemConcepts课程概况(2/4)教学内容教学要求MemoryManagement掌握固定分区,可变分区,段式,页式存储管理原理与算法VirtualMemory虚拟存储是操作系统另一个重要概念。要求学生正确的理解虚存的概念熟练掌握请求页式的地址变换过程以及常用的页面置换算法FileSystems掌握文件系统的基本概念，熟练使用文件系统的操作方法I/OSystems掌握I/O系统的基本概念，理解设备驱动程序。弄清从用户请求到设备完成用户请求的全过程Mass-StorageStructure了解几种磁盘调度算法OperatingSystemConcepts课程概况(3/4)学时：64学时教材操作系统概念（第七版影印版）西尔伯莎茨编著高教社2007OperatingSystemConcepts课程概况(4/4)考核方式闭卷考试成绩评定:由下述三部分组成期末考试成绩期中考试成绩平时成绩（作业、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,

进入赫尔辛基大学计算机系1989，进入芬兰陆军，服11个月的兵役，主要服务于计算机部门1990，退伍後回到大学，开始接触Unix。根据安德鲁·斯图尔特·塔能鲍姆所著的教科书及minix源码，打造了自己的操作系统1991，在网络上发布Linux内核OperatingSystemConceptsLinusTorvalds

StoryOne

SelectedQuotesfromLinusTorvaldsOperatingSystemConcepts"MynameisLinusTorvaldsandIamyourgod."——在1998Linux大会上的自我介绍StoryOne

SelectedQuotesfromLinusTorvaldsOperatingSystemConcepts"那年夏天我做了两件事。第一件事是什么都没做。第二件事是读完了719页的《操作系统：设计和执行》。那本红色的简装本教科书差不多等于睡在了我的床上。"——关于暑假StoryOne

OperatingSystemConcepts"Linux不是靠牺牲宝贵的睡眠时间换来的。事实上，如果你想听真话，那我就要说，我更喜欢睡觉。"——关于超时工作SelectedQuotesfromLinusTorvaldsStoryOne

OperatingSystemConcepts"寻找乐趣，做一些有趣的事情，增加财富和提高名声。"——关于生活哲学SelectedQuotesfromLinusTorvaldsStoryOne

OperatingSystemConceptsStoryTwo

AMS在奋进号舱内2011年5月19日5:15安装完毕，9:35开始接收数据77AMSPayloadandOperationControlCenterGeneva,SwitzerlandAMSDataFlow约翰逊航天中心（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利用率大大提高用户无控制权，无交互性，延迟大引入多道程序设计技术的根本目的：

提高CPU的利用率，充分发挥并行性，

这包括：程序之间；设备之间；设备与CPU之间均并行工作。OperatingSystemConcepts例：有两道程序A、B，按下图以多道程序方式运行，要求在右图画出它们的运行轨迹，并计算在60ms内，CPU的利用率，假设起始时首先运行B，并允许忽略监督程序切换A、B的时间。OperatingSystemConcepts运行15msI/O20ms运行10msI/O10msABBAI/OI/O10ms60mstBA请画个示意图。OperatingSystemConcepts解：BAI/OI/O1060t20304050253545若在单道程序系统中，CPU的利用率是多少？OperatingSystemConcepts为了说明多道程序的优点，不妨参考RTurner提出的例子：某计算机系统，有256KB的主存(不包含操作系统)，一个磁盘，一个终端和一台打印机。同时提交的三个作业分别命名为JOB1、JOB2、JOB3。各作业运行时间分别为5min、15min和10min。它们对资源的使用情况如下表所示：OperatingSystemConcepts作业名作业类型所需主存/KB所需磁盘所需终端所需打印机运行时间/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10三个作业的执行要求OperatingSystemConcepts假定JOB1主要使用CPU处理数据，JOB2主要使用终端进行作业的输入，JOB3运行时主要使用磁盘和打印机，后两作业都只需要较少的CPU时间。对于简单批处理情况，这些作业将按顺序执行。JOB1运行5min完成，JOB2在等待5min后，运行15min完成，JOB3在等待20min后开始执行。三个作业全部完成需要30min(这三个作业是一批)。OperatingSystemConcepts采用多道程序设计技术，可让这三个作业并行运行。由于它们运行中几乎不同时使用同一资源，所以三个作业可同时运行。JOB1在进行数据处理的同时，JOB2在终端上进行作业输入，JOB3在使用磁盘和打印机。因此，JOB1只需5min完成，JOB2需15min完成，JOB3需10min完成。这样三个作业全部完成的时间只需15min，显然系统处理效率明显提高。OperatingSystemConceptsTime-SharingSystems–InteractiveComputing（1/2）Interactivecomputersystemprovidesdirectcommunicationbetwe