操作系統(tǒng)教學課件：Chapter 1 Introduction

OperatingSystems

操作系統(tǒng)Aboutthiscourse（1）推薦教材和參考資料：OperatingSystemConcepts，高教，AbrahamSilberschatzandPeterGalvin，第六、七版OperatingSystemsDesignandImplementation(SecondEdition)，機械，AndrewS.Tanenbaum《操作系統(tǒng)原理》，華中理工大學，龐麗萍《操作系統(tǒng)原理》，清華大學，屠立德《操作系統(tǒng)實驗教程》，清華大學，胡峰松、肖德貴，2009Aboutthiscourse（2）課堂講授：64學時，包括講解習題和復習雙語課，ppt基本上是用英文，關(guān)鍵概念和術(shù)語會用中文標注設(shè)計操作系統(tǒng)，基礎(chǔ)知識和代碼實驗：小班討論8學時，實驗16學時加深對原理的理解Aboutthiscourse（3）作業(yè)：每章都會有習題，獨立完成成績評定：平時成績15%（作業(yè)、考勤、提問）+期中考試15%+實驗成績20%+期終考試50%（閉卷）Chapter1IntroductionWhatisanOperatingSystem?MainframeSystemsDesktopSystemsMultiprocessorSystemsDistributedSystemsClusteredSystemReal-TimeSystemsHandheldSystemsComputingEnvironmentsUnderstandOS？？想利用計算機這個工具幫助解決問題計算機是由一些電子元器件組成、具有邏輯和算術(shù)運算能力，一般包括處理、存儲、傳輸三個部分硬件做一臺計算機（電子元器件、計算機組成原理的知識……）買/配機器（cpu、內(nèi)存、主板、顯卡、網(wǎng)卡、硬盤、機箱……）軟件操作系統(tǒng)買一個下載一個免費的自己設(shè)計一個系統(tǒng)軟件應用程序……UnderstandOS？？利用計算機解決問題，實際就是把人的意識轉(zhuǎn)換成計算機可以理解的內(nèi)容，讓計算機硬件完成運算，最后把結(jié)果反饋給用戶硬件提供一些手段（指令）可以對其進行操作和了解其運行狀態(tài)人們可以直接操作硬件（提供的指令系統(tǒng)），早期的專家只能這樣，現(xiàn)在的發(fā)燒友可以這樣更多的用戶，利用操作系統(tǒng)和應用軟件從通電啟動的過程看：硬件（BIOS）->OS->應用程序從解決問題的角度：用戶->應用程序->OS->硬件UnderstandOS？？我們已經(jīng)有的基礎(chǔ)計算機組成與結(jié)構(gòu)有哪些部件（CPU、存儲器、I/O）如何連接（三總線）如何工作（同步、異步）編程語言（C、Java？）、數(shù)據(jù)結(jié)構(gòu)、編程技術(shù)（程序設(shè)計基礎(chǔ)、高等程序設(shè)計）怎么樣把人的思想變成計算機可以理解的形式典型的理解是硬件和軟件如何把硬件和軟件統(tǒng)一起來呢？OS是基礎(chǔ)OS是一個系統(tǒng)，一個復雜的軟件系統(tǒng)，是我們從系統(tǒng)的角度來理解計算機的起點UnderstandOS？？System：Agroupofinteracting,interrelated,orinterdependentelementsformingacomplexwhole.系統(tǒng)：組成一個復雜的整體的一組互相作用、互相聯(lián)系或互相依存的元素OS作為一個軟件系統(tǒng)，它也會包含許多元素，這些元素之間會相互作用、相互聯(lián)系或相互依存OS這門課的目的就是使同學們能夠掌握操作系統(tǒng)的基本概念、原理、內(nèi)部結(jié)構(gòu)、設(shè)計開發(fā)技術(shù)，培養(yǎng)基本的系統(tǒng)能力，提高對計算機系統(tǒng)的整體理解，為學習后續(xù)相關(guān)課程打下必要的知識基礎(chǔ)。本課程的教學內(nèi)容主要包括操作系統(tǒng)概述，操作系統(tǒng)運行環(huán)境，處理器管理，進程同步、通信與死鎖，存儲管理，文件管理，設(shè)備管理，安全與保護，實例研究等。ComputerSystemComponents1. Hardware

–providesbasiccomputingresources(CPU,memory,I/Odevices).2. Operatingsystem

–controlsandcoordinatestheuseofthehardwareamongthevariousapplicationprogramsforthevarioususers.3. Applicationsprograms

–definethewaysinwhichthesystemresourcesareusedtosolvethecomputingproblemsoftheusers(compilers,databasesystems,videogames,businessprograms).4. Users(people,machines,othercomputers).AbstractViewofSystemComponentsWhatisanOperatingSystem?Aprogramthatmanages

thecomputer

hardwareAprogramthatactsasanintermediary

（中間人、媒介）betweenauserofacomputerandthecomputerhardware.Operatingsystemgoals:Executeuserprogramsandmakesolvinguserproblemseasier.Makethecomputersystemconvenienttouse.Usethecomputerhardwareinanefficient

manner.OperatingSystemDefinitionsResourceallocator

資源分配者–managesandallocatesresources.Controlprogram

控制程序–controlstheexecutionofuserprogramsandoperationsofI/Odevices.Kernel

內(nèi)核–theoneprogramrunningatalltimes(allelsebeingapplicationprograms).想想其他一些應用程序的啟動，如word站在系統(tǒng)資源和OS的角度看Usersview從用戶角度看VariesbytheinterfacebeingusedInfrontofaPC-monitor,keyboard,mouse,systemunitMonopolizeitsresources->easeofuse獨占資源型AterminalconnectedtoamainframeorminicomputerShareresources->maximizeresourceutilization共享資源型WorkstationconnectedtonetworksofotherworkstationsandserversOwnandshareresources->compromisebetweenindividualusabilityandresourceutilization獨占和共享資源型Handheld手持型Usedbysingleindividualuser->individualuseandpowerNouserSimplylogicoperation->runwithoutuserinterventionHistoryofOS計算機的發(fā)展推動了OS的出現(xiàn)和發(fā)展MainframeSystems大型機系統(tǒng)ReducesetuptimebybatchingsimilarjobsAutomaticjobsequencing–automaticallytransferscontrolfromonejobtoanother.Firstrudimentaryoperatingsystem.Job（作業(yè)）:program,data,controlinformationResidentmonitorinitialcontrolinmonitorcontroltransferstojobwhenjobcompletescontroltransferspacktomonitor1964年，IBM推出了第一代計算機操作系統(tǒng)：System/360，1970年推出了System/370?，1983年推出了System/370ExtendedArchitecture(370-XA)，1990年推出了EnterpriseSystemsArchitecture/390(ESA/390)，2000年z/Architecture?，F(xiàn)在Mainframe被歸為大型商業(yè)服務器一類曾經(jīng)計算機很“笨貴”MemoryLayoutforaSimpleBatchSystemMultiprogrammedBatchSystems多道程序批處理系統(tǒng)Severaljobsarekeptinmainmemoryatthesametime,andtheCPUismultiplexedamongthem.MultiprogrammedBatchSystems(Cont.)OSFeaturesNeededforMultiprogramming

OS如何才能提供多道程序I/Oroutinesuppliedbythesystem.Memorymanagement–thesystemmustallocatethememorytoseveraljobs.Jobscheduling（作業(yè)調(diào)度）–selectjobsfromjobpooltomainmemoryCPUscheduling（CPU調(diào)度）–thesystemmustchooseamongseveraljobsreadytorun.Allocationofdevices.Time-SharingSystems–InteractiveComputing

分時共享系統(tǒng)-交互式計算TheCPUismultiplexedamongseveraljobsthatarekeptinmemoryandondisk(theCPUisallocatedtoajobonlyifthejobisinmemory).Ajobswappedinandoutofmemorytothedisk.Needfilesystemanddiskmanagement.On-linecommunicationbetweentheuserandthesystemisprovided;whentheoperatingsystemfinishestheexecutionofonecommand,itseeksthenext“controlstatement”fromtheuser’skeyboard.On-linesystemmustbeavailableforuserstoaccessdataandcode.計算機為人服務DesktopSystemsPersonalcomputers

–computersystemdedicatedtoasingleuser.I/Odevices–keyboards,mice,displayscreens,smallprinters.Userconvenienceandresponsiveness.Canadopttechnologydevelopedforlargeroperatingsystem’oftenindividualshavesoleuseofcomputeranddonotneedadvancedCPUutilizationofprotectionfeatures.Mayrunseveraldifferenttypesofoperatingsystems(Windows,MacOS,UNIX,Linux)后來計算機很“白菜”ParallelSystemsMultiprocessorsystemswithmorethanoneCPUinclosecommunication.Tightlycoupledsystem（緊耦合）

–processorssharememoryandaclock;communicationusuallytakesplacethroughthesharedmemory.Advantagesofparallelsystem:IncreasedthroughputEconomical

Increasedreliabilitygracefuldegradationfail-softsystems我們需要超級計算機ParallelSystems(Cont.)Symmetricmultiprocessing(SMP)Eachprocessorrunsandidenticalcopyoftheoperatingsystem.Manyprocessescanrunatoncewithoutperformancedeterioration.MostmodernoperatingsystemssupportSMPAsymmetricmultiprocessingEachprocessorisassignedaspecifictask;masterprocessorschedulesandallocatedworktoslaveprocessors.MorecommoninextremelylargesystemsSymmetricMultiprocessingArchitectureDistributedSystemsDistributethecomputationamongseveralphysicalprocessors.Looselycoupledsystem（松耦合）

–eachprocessorhasitsownlocalmemory;processorscommunicatewithoneanotherthroughvariouscommunicationslines,suchashigh-speedbusesortelephonelines.Advantagesofdistributedsystems.ResourcesSharingComputationspeedup–loadsharingReliabilityCommunicationsDistributedSystems(cont)Requiresnetworkinginfrastructure.Localareanetworks(LAN)orWideareanetworks(WAN)Maybeeitherclient-serverorpeer-to-peersystems.計算機需要聯(lián)網(wǎng)GeneralStructureofClient-ServerClusteredSystemsClusteringallowstwoormoresystemstosharestorage.Differingfrompara.systemintheyarecomposedofindividualsystemscoupledtogethersharingstorageandlinkedviaLANnetworking.Provideshighreliability/availability.Asymmetricclustering:oneserverrunstheapplicationwhileotherserversstandby.Symmetricclustering:allNhostsarerunningtheapplication.我們需要廉價的網(wǎng)絡共享計算資源Real-TimeSystemsOftenusedasacontroldeviceinadedicatedapplicationsuchascontrollingscientificexperiments,medicalimagingsystems,industrialcontrolsystems,andsomedisplaysystems.Well-definedfixed-timeconstraints.Real-Timesystemsmaybeeitherhardorsoftreal-time.計算機無處不為我們服務Real-TimeSystems(Cont.)Hardreal-time:Secondarystoragelimitedorabsent,datastoredinshorttermmemory,orread-onlymemory(ROM)Conflictswithtime-sharingsystems,notsupportedbygeneral-purposeoperatingsystems.

Softreal-timeLimitedutilityinindustrialcontrolofroboticsUsefulinapplications(multimedia,virtualreality)requiringadvancedoperating-systemfeatures.HandheldSystemsPersonalDigitalAssistants(PDAs)CellulartelephonesIssues:LimitedmemorySlowprocessorsSmalldisplayscreens.Operatingsystemzoo有哪些操作系統(tǒng)？從歷史演變可以看出，OS作為計算機系統(tǒng)資源的管理者和分配者，肯定依賴于具體的計算機系統(tǒng)類型，隨著計算機系統(tǒng)的演變以及不同的應用，可以大致對OS進行一些分類MainframeOSForhighendmainframes1000disks,millionsofgigabytesofdataHighendwebservers,serversforlarge-scaleelectronicommercesites,serversforB2BtransactionsProcessmanyjobsatonce,needprodigiousamountsofI/OTypicallyoffer3kindsofservices:Batch,transactionprocessing,timesharingExample:OS/390,LinuxServerOSRunonserversLargePC,workstation,mainframeMultipleusersatonceoveranetworkAllowuserstosharehardwareandsoftwareExample:Solaris,FreeBSD,Linux,Windowsserver200xMultiprocessorOSMultipleCPUsintoasinglesystemDependingonpreciselyhowtheyareconnectedandwhatisshared,thesesystemsarecalledparallelcomputers,multicomputers,multiprocessorsTheseOSareoftenvariationsontheServerOS,withspecialfeatureforcommunication,connectivity,consistencyEvenconventionaldesktopandnotebookOSsarestartingtodealwithatleastsmall-scalemultiprocessorsExample:Windows,LinuxPersonalcomputerOSSingleuserWordprocessing,spreadsheets,games,Internetaccess……Example:Windows,Linux,FreeBSD,MacintoshOSHandheldcomputerOSSmallerandsmallersystems,basedon32-bitCPUswithprotectedmodeandrunonsophisticatedOSPDA,mobilephoneExample:SymbianOS,PalmOSAndroid,iOS,WPEmbeddedOSControldevicesthatarenotgenerallythoughtofascomputersandwhichdonotacceptuser-installedsoftwareMicrowaveovens,TVsets,cars,DVDrecorders,cellphones,MP3players……ThemainpropertywhichdistinguishesembeddedsystemsfromhandheldsisthecertaintythatnountrustedsoftwarewilleverrunonitExample:QNX,VxWorksSensorNodeOSTinycomputersthatcommunicatewitheachotherandwithabasestationusingwirelesscommunicationLimitedpower,berobustenoughtotoleratefailuresofindividualnodesNeedrealOS,usuallyonewitheventdriven,smallandsimple,alsowithembeddedsystems.Example:TinyOSReal-timeOSHavetimeasakeyparameterHardrealtime,industrialprocesscontrol,carSoftrealtime,digitalaudioormultimedia,digitaltelephoneSincemeetingstrictdeadlinesiscrucialin(hard)realtimesystems,sometimestheOSissimplyalibrarylinkedwiththeapplicationprograms,witheverythingtightlycoupledandnoprotectionbetweenpartsofsystemExample:e-Cos,RTLinux,VRTX,RTOS,RTWINDOWSHandheld,embeddedsystem,realtimesystemoverlapconsiderably.SmartcardOSSmallestOSrunonsystemcontainingaCPUchipwithsevereprocessingandmemoryconstraints.EvenpowerissuppliedbyotherdevicesUsuallyhasaJVMComputingEnvironmentsTraditionalcomputingDesktop,parallel,distributed,gridWeb-BasedComputingEmbeddedComputingComputingEnvironments(c)時代在發(fā)展……需要什么樣的操作系統(tǒng)？或者還會有OS這個概念嗎？CC-CloudComputing從購買軟硬件到購買服務。軟件即服務（SoftwareasaService，SaaS），平臺即服務（PlatformasaService，PaaS），基礎(chǔ)設(shè)施即服務（InfrastructureasaService，IaaS）IOT