中科大操作系统课件01.ppt

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1、MODERN OPERATING SYSTEMSThird EditionANDREW S.TANENBAUMChapter 1IntroductionTanenbaum,Modern Operating Systems 3 e,(c)2008 Prentice-Hall,Inc.All rights reserved.0-13-6006639OutlinenWhat is an operating systemnThe history of Operating SystemnHardware of operating systemnImportant concepts of Operatin

2、g SystemWhat Is An Operating SystemA modern computer consists of:One or more processorsMain memoryDisksPrintersVarious input/output devicesManaging all these components requires a layer of software the operating systemTanenbaum,Modern Operating Systems 3 e,(c)2008 Prentice-Hall,Inc.All rights reserv

3、ed.0-13-6006639What is an Operating System?nA modern computer is very complex.qNetworkingqDisksqVideo/audio cardq.nIt is impossible for every application programmer to understand every detailnA layer of computer software is introduced to provide a better,simpler,cleaner model of the resources and ma

4、nage themWhat Is An Operating SystemFigure 1-1.Where the operating system fits in.Tanenbaum,Modern Operating Systems 3 e,(c)2008 Prentice-Hall,Inc.All rights reserved.0-13-6006639What is an Operating System?nUsers use various OSqWindows,Linux,Mac OS etc.nUser interacts with shell or GUIqpart of OS?q

5、they use OS to get their work donenIs device driver part of OS?What is an Operating System?nOn top of hardware is OSnMost computers have two modes of operation:qKernel mode and user modeqOS runs in kernel mode,which has complete access to all hardware and can execute any instructionqRest of software

6、 runs in user mode,which has limited capabilityqShell or GUI is the lowest level of user mode softwareWhat is an operating system?nTwo functions:qFrom top to down:provide application programmers a clean abstract set of resources instead of hardware ones qFrom down to top:Manage these hardware resour

7、cesThe Operating System as an Extended MachineFigure 1-2.Operating systems turn ugly hardware into beautiful abstractions.Tanenbaum,Modern Operating Systems 3 e,(c)2008 Prentice-Hall,Inc.All rights reserved.0-13-6006639As an extended machinenAbstraction:qCPUprocessqStorage-filesqMemory address space

8、n4 types of people:qIndustrial engineer:design hardwareqKernel designerqApplication programmer:OSs userqEnd usersThe Operating System as a Resource ManagerAllow multiple programs to run at the same timeManage and protect memory,I/O devices,and other resourcesIncludes multiplexing(sharing)resources i

9、n two different ways:In timeIn spaceTanenbaum,Modern Operating Systems 3 e,(c)2008 Prentice-Hall,Inc.All rights reserved.0-13-6006639As a resource managernModern OS runs multiple programs of multiple users at the same timeqImagine what would happen if several programs want to print at the same time?

10、qHow to account the resource usage of each process?qResources can be multiplexed:nHow to ensure fairness and efficiency?summarynOperating system is a softwareqIs a complex softwareqRuns in kernel modeqManages hardwareqProvide a friendly interface for application programmerHistory of Operating System

11、sGenerations:(194555)Vacuum Tubes(195565)Transistors and Batch Systems(19651980)ICs and Multiprogramming(1980Present)Personal ComputersTanenbaum,Modern Operating Systems 3 e,(c)2008 Prentice-Hall,Inc.All rights reserved.0-13-60066391st:vacuum tubesnLarge and slownEngineers design,build,operate and m

12、aintain the computernAll programming is done with machine language,or by wiring circuits using cablesninsert plugboards into the computer and operatenThe work is mainly numerical calculations2nd:transistors and batch systemsnAlso called mainframesnComputers are managed by professional operatorsnProg

13、rammers use punch card to run programs;operators operate(load compiler,etc)and collect output to the usernComplains soon come:qHuman Operation between computer operationqLead to batch systemqCollect a batch of jobs in the input room,then read them into a magnetic tape;the same for output2nd:Transist

14、ors and Batch Systems(1)Figure 1-3.An early batch system.(a)Programmers bring cards to 1401.(b)1401 reads batch of jobs onto tape.Tanenbaum,Modern Operating Systems 3 e,(c)2008 Prentice-Hall,Inc.All rights reserved.0-13-6006639Transistors and Batch Systems(2)Figure 1-3.(c)Operator carries input tape

15、 to 7094.(d)7094 does computing.(e)Operator carries output tape to 1401.(f)1401 prints output.Tanenbaum,Modern Operating Systems 3 e,(c)2008 Prentice-Hall,Inc.All rights reserved.0-13-6006639Transistors and Batch Systems(4)Figure 1-4.Structure of a typical FMS job.Tanenbaum,Modern Operating Systems

16、3 e,(c)2008 Prentice-Hall,Inc.All rights reserved.0-13-60066393rd:IC and MultiprogrammingnOS/360:a dinosaur stuck in a tar pitqAims to adapts 1401/7904,covers all trades of lifeqHowever,OS/360 introduces several key techniquesnMulti-programming:solve the problem of CPU idlingnSpooling:simultaneous p

17、eripheral operation on lineqWhenever a job finishes,OS load a new job from disk to the empty-partitionFigure 1-5.A multiprogramming system with three jobs in memory.3rd:ICs and MultiprogrammingTanenbaum,Modern Operating Systems 3 e,(c)2008 Prentice-Hall,Inc.All rights reserved.0-13-60066393rd:Ics an

18、d MultiprogrammingnProblems:q3rd generation OS was well suited for big scientific calculations and massive data processingqBut many programmers complain a lot for not be able to debug quickly.Why?qAnd the solution to this problem would be.?qTimesharing:nA variant of multiprogrammingnProvide both fas

19、t interactive service but also fits big batch work3rd:IC and MultiprogrammingnA system to be remembered:MULTICSqA machine that would support hundreds of simultaneous timesharing users like the electricity system(like a web server nowadays)qIntroduces many brilliant ideas but enjoys no commercial suc

20、cessqIts step-child is the well-known and time-honored UNIXqSystem V/FreeBSD,MINIX,Linux4th:personal computersnComputers have performance similar to 3rd generation,but prices drastically differentnCP/MqFirst disk-based OSn1980,IBM PC,Basic Interpreter,DOS,MS-DOSnGUI-LisaApple:user friendlynMS-DOS wi

21、th GUI Win95/98/mewinNT/xpSummaryn4 generations OSnDevelops with hardware and user needsnMulti-user,multi-programming,time-sharingComputer Hardware ReviewFigure 1-6.Some of the components of a simple personal computer.Tanenbaum,Modern Operating Systems 3 e,(c)2008 Prentice-Hall,Inc.All rights reserv

22、ed.0-13-6006639Hardware:processornBrain of computerqFetches instruction from memory and executeqCycle of CPU:nfetch,decode,executeqCPU has registers to store variable and temporary result:load from memory to register;store from register to memoryqProgram counter:next instruction to fetchqStack point

23、er:the top of the current stackqPSW:program status word,priority,modeA referencenAdam Smith:Wealth of NationnOf the Division of labornOne man draws out the wire,another straights it,a third cuts it,a fourth points it,a fifth grinds it at the topnOne person could make up to forth-eight thousand pins

24、in a dayCPU PipeliningFigure 1-7.(a)A three-stage pipeline.(b)A superscalar CPU.Tanenbaum,Modern Operating Systems 3 e,(c)2008 Prentice-Hall,Inc.All rights reserved.0-13-6006639CPU PipelinenAccelerate the executionnCause headaches to OS/compiler writersnFor superscalar:instructions are often execute

25、d out of order Figure 1-8.(a)A quad-core chip with a shared L2 cache.(b)A quad-core chip with separate L2 caches.Multithreaded and Multicore ChipsTanenbaum,Modern Operating Systems 3 e,(c)2008 Prentice-Hall,Inc.All rights reserved.0-13-6006639Figure 1-9.A typical memory hierarchy.The numbers are ver

26、y rough approximations.Memory(1)Tanenbaum,Modern Operating Systems 3 e,(c)2008 Prentice-Hall,Inc.All rights reserved.0-13-6006639memorynMemory is where computer fetch and store data,ideally,it should be both chip/largenThe best people can do,is to construct a memory hierarchynCache lines:qMemory div

27、ided into cache lines;the mostly used ones are stored in cachesqCache hit,cache missqCache:whenever there is disparity in usage or speed;used to improve performance Questions when dealing with cache:When to put a new item into the cache.Which cache line to put the new item in.Which item to remove fr

28、om the cache when a slot is needed.Where to put a newly evicted item in the larger memory.Memory(2)Tanenbaum,Modern Operating Systems 3 e,(c)2008 Prentice-Hall,Inc.All rights reserved.0-13-6006639Figure 1-10.Structure of a disk drive.DisksTanenbaum,Modern Operating Systems 3 e,(c)2008 Prentice-Hall,

29、Inc.All rights reserved.0-13-6006639DisksnCheap and large:two orders better than RAMnSlow:three orders worse than RAMnMechanical movement to fetch datanOne or more platterrotate rpmnInformation is stored on concentric circlesnArm,track,cylinder,sectornDisk helps to implement Virtual MemoryqWhen no e

30、nough memory is available,disks are used as the storage,and memory as cacheFigure 1-11.(a)The steps in starting an I/O device and getting an interrupt.I/O DevicesTanenbaum,Modern Operating Systems 3 e,(c)2008 Prentice-Hall,Inc.All rights reserved.0-13-6006639I/O devicesnTwo parts:a controller and a

31、devicenController:to provide a simpler interface to OSnDevice driver:talks to controller,give commands and accepts responsenBusy waiting/interrupt/DMABooting the ComputernBIOSbasic input/output systemqOn the parentboard,low-level I/O softwareqChecks RAM,keyboard and other basic devicesqDetermine the

32、 boot device:floppy,CD-ROM,diskqFirst sector of the boot-device is read into memoryqThe sector contains program to check which partition is activeqThen a secondary boot-loader is read into memory and reads in operating system from the active partitionThe Operating System ZooMainframe operating syste

33、msServer operating systemsMultiprocessor operating systemsPersonal computer operating systemsHandheld operating systemsEmbedded operating systemsSensor node operating systemsReal-time operating systemsSmart card operating systemsTanenbaum,Modern Operating Systems 3 e,(c)2008 Prentice-Hall,Inc.All ri

34、ghts reserved.0-13-6006639ProcessesAddress spacesFilesInput/OutputProtectionThe shellOntogeny recapitulates phylogenyLarge memoriesProtection hardwareDisksVirtual memoryOperating System ConceptsTanenbaum,Modern Operating Systems 3 e,(c)2008 Prentice-Hall,Inc.All rights reserved.0-13-6006639processes

35、nProcessqAddress space:0-4G;executable program,programs data,and its stackqOther resources like:registers,files,alarms,related processes,and other informationqA process is fundamentally a container that holds information for a program to runProcessesFigure 1-13.A process tree.Process A created two c

36、hild processes,B and C.Process B created three child processes,D,E,and F.Tanenbaum,Modern Operating Systems 3 e,(c)2008 Prentice-Hall,Inc.All rights reserved.0-13-6006639Address SpacenThe memory used by a process,in conceptnMOS allows multiple processes in memory simultaneouslynSome processes need m

37、ore memory than physically available virtual memoryFigure 1-14.A file system for a university department.Files(1)Tanenbaum,Modern Operating Systems 3 e,(c)2008 Prentice-Hall,Inc.All rights reserved.0-13-6006639Figure 1-15.(a)Before mounting,the files on the CD-ROM are not accessible.(b)After mountin

38、g,they are part of the file hierarchy.Files(2)Tanenbaum,Modern Operating Systems 3 e,(c)2008 Prentice-Hall,Inc.All rights reserved.0-13-6006639Figure 1-16.Two processes connected by a pipe.Files(3)Tanenbaum,Modern Operating Systems 3 e,(c)2008 Prentice-Hall,Inc.All rights reserved.0-13-6006639System

39、 calls nSystem calls is the interface users contact with OS and hardwarenSystem calls vary from system to system,but the underlying concepts are similarFigure 1-17.The 11 steps in making the system call read(fd,buffer,nbytes).System CallsTanenbaum,Modern Operating Systems 3 e,(c)2008 Prentice-Hall,I

40、nc.All rights reserved.0-13-6006639Figure 1-18.Some of the major POSIX system calls.System Calls for Process ManagementTanenbaum,Modern Operating Systems 3 e,(c)2008 Prentice-Hall,Inc.All rights reserved.0-13-6006639Figure 1-18.Some of the major POSIX system calls.System Calls for File Management(1)

41、Tanenbaum,Modern Operating Systems 3 e,(c)2008 Prentice-Hall,Inc.All rights reserved.0-13-6006639Figure 1-18.Some of the major POSIX system calls.System Calls for File Management(2)Tanenbaum,Modern Operating Systems 3 e,(c)2008 Prentice-Hall,Inc.All rights reserved.0-13-6006639Figure 1-18.Some of th

42、e major POSIX system calls.Miscellaneous System CallsTanenbaum,Modern Operating Systems 3 e,(c)2008 Prentice-Hall,Inc.All rights reserved.0-13-6006639Figure 1-19.A stripped-down shell.A Simple ShellTanenbaum,Modern Operating Systems 3 e,(c)2008 Prentice-Hall,Inc.All rights reserved.0-13-6006639Figur

43、e 1-20.Processes have three segments:text,data,and stack.Memory LayoutTanenbaum,Modern Operating Systems 3 e,(c)2008 Prentice-Hall,Inc.All rights reserved.0-13-6006639Figure 1-21.(a)Two directories before linking/usr/jim/memo to asts directory.(b)The same directories after linking.LinkingTanenbaum,M

44、odern Operating Systems 3 e,(c)2008 Prentice-Hall,Inc.All rights reserved.0-13-6006639Figure 1-22.(a)File system before the mount.(b)File system after the mount.MountingTanenbaum,Modern Operating Systems 3 e,(c)2008 Prentice-Hall,Inc.All rights reserved.0-13-6006639Figure 1-23.The Win32 API calls th

45、at roughly correspond to the UNIX calls of Fig.1-18.Windows Win32 APITanenbaum,Modern Operating Systems 3 e,(c)2008 Prentice-Hall,Inc.All rights reserved.0-13-6006639Monolithic systems basic structure:A main program that invokes the requested service procedure.A set of service procedures that carry

46、out the system calls.A set of utility procedures that help the service procedures.Operating Systems StructureTanenbaum,Modern Operating Systems 3 e,(c)2008 Prentice-Hall,Inc.All rights reserved.0-13-6006639Figure 1-25.Structure of the THE operating system.Layered SystemsTanenbaum,Modern Operating Sy

47、stems 3 e,(c)2008 Prentice-Hall,Inc.All rights reserved.0-13-6006639Figure 1-26.Structure of the MINIX 3 system.MicrokernelsTanenbaum,Modern Operating Systems 3 e,(c)2008 Prentice-Hall,Inc.All rights reserved.0-13-6006639Figure 1-27.The client-server model over a network.Client-Server ModelTanenbaum

48、,Modern Operating Systems 3 e,(c)2008 Prentice-Hall,Inc.All rights reserved.0-13-6006639Figure 1-29.(a)A type 1 hypervisor.(b)A type 2 hypervisor.Virtual Machines(2)Tanenbaum,Modern Operating Systems 3 e,(c)2008 Prentice-Hall,Inc.All rights reserved.0-13-6006639The C languageHeader filesLarge progra

49、mming projectsThe model of run timeThe World According to CTanenbaum,Modern Operating Systems 3 e,(c)2008 Prentice-Hall,Inc.All rights reserved.0-13-6006639World according to CnOperating systems are large C programs consisting of many pieces written by many programmersnC languageqData types,variable

50、s,control statementsqHeader files:declaration,definition,macrosqFor a large programming projectFigure 1-30.The process of compiling C and header files to make an executable.The Model of Run TimeTanenbaum,Modern Operating Systems 3 e,(c)2008 Prentice-Hall,Inc.All rights reserved.0-13-6006639Large pro