西安交大操作系統(tǒng)課件cch02-structure

1、Module 2: Computer-System Structures計(jì)算機(jī)系統(tǒng)結(jié)構(gòu)Computer System Operation 計(jì)算機(jī)系統(tǒng)操作Storage Structure 存儲(chǔ)構(gòu)造Storage Hierarchy 存儲(chǔ)層次Hardware Protection 硬件保護(hù)Computer-System Architecture計(jì)算機(jī)系統(tǒng)體系結(jié)構(gòu)Computer-System Operation計(jì)算機(jī)系統(tǒng)操作I/O devices and the CPU can execute concurrently. I/O 設(shè)備與CPU可并行運(yùn)行Each device controller

2、 is in charge of a particular device type. 每一設(shè)備控制器負(fù)責(zé)一個(gè)設(shè)備類(lèi)型 Each device controller has a local buffer. 每一設(shè)備控制器有一局部緩存 CPU moves data from/to main memory to/from local buffers CPU 通過(guò)局部緩存與主存交換數(shù)據(jù) I/O is from the device to local buffer of controller. I/O從設(shè)備到設(shè)備控制器的局部緩存Device controller informs CPU that it

3、has finished its operation by causing an interrupt. 設(shè)備控制器通過(guò)引起中斷通知CPU操作已完成中斷機(jī)制hardware interrupt硬件中斷device controller informs CPU that it has finished its operation by causing an interruptdisk, timer, etc.software interrupt (trap)軟件中斷（陷阱）a trap (or an exception異常)division by zero, invalid memory acce

4、ssa system call 系統(tǒng)調(diào)用(also called a monitor call)read( ), write( )Why the interrupt?make the system more efficient and meanwhile more responsivecommon functions of interruptsa modern operating system is interrupt driven 現(xiàn)代操作系統(tǒng)是中斷驅(qū)動(dòng)的interrupt transfers control to the interrupt service routine (interru

5、pt handler) generally 中斷將控制權(quán)轉(zhuǎn)移到中斷服務(wù)程序a generic routine to examine the interrupt information, and in turn call the specific handlerthrough the interrupt vector, which contains the addresses of all the service routinese.g. MS-DOS, UNIXseparate segments of code determine what action should be taken for

6、 each type of interruptI/O Structureperipheral device(s) attached to device controller設(shè)備與設(shè)備控制器相連a device controller (hardware)local buffer storage 本地緩沖器a set of registers 一組寄存器device driver, usually a software program embedded into an OS設(shè)備驅(qū)動(dòng)程序I/O Interruptstwo ways of an I/O operation 兩種I/O操作Synchro

7、nous 同步Asynchronous異步synchronous I/O mode: after I/O starts, control returns to user program only upon I/O completionasynchronous I/O mode: after I/O starts, control returns to user program without waiting for I/O completionthe user program will be notified about the I/O completion on a later timeWi

8、ndows message, or call back functionsynchrounous asynchrounoussynchronous I/Obusy wait method 忙等方式wait instruction idles the CPU until the next interruptwait loop (contention for memory access)Loop: jmp Loopdrawbacks: at most one I/O request is outstanding at a time, no simultaneous I/O processingin

9、terrupt based method: multiple I/O 中斷方式device-status table contains entry for each I/O device indicating its type, address, and statea wait queue (a list of waiting requests) for each I/O devicedevice-status table & wait queueDMA structurelow speed device like a typical terminal input device leaves

10、most CPU time for other operationsusually assigned a low interrupt priority, allowing other more important interrupts to be processed firsthigh-speed I/O devices able to transmit information at close to memory speedsif the CPU needs to respond to each interrupt for every byte, it does not have much

11、time for process executionDirect Memory AccessDMA - device controller transfers blocks of data from buffer storage directly to main memory without CPU intervention設(shè)備控制器在本地緩沖和內(nèi)存之間直接傳輸一整塊數(shù)據(jù)而無(wú)需CPU干預(yù)setting up buffers, pointers, and countersonly one interrupt is generated per block, rather than the one

12、interrupt per byteDMA controller steals memory cycles from CPU DMA控制器從CPU中竊取內(nèi)存周期Storage-Device Hierarchy存儲(chǔ)設(shè)備層次寄存器緩存主存儲(chǔ)器電子盤(pán)磁盤(pán)光盤(pán)磁帶speedcostcapacityStorage systems organized in hierarchy.存儲(chǔ)系統(tǒng)分層組織Speed 速度cost 成本volatility 易失性Main Memoryrandom access memory (RAM, DRAM)main memory are the only large stora

13、ge that the CPU can access directly CPU可以直接訪問(wèn)的唯一大型存儲(chǔ)介質(zhì)store data and instructionsproblems with RAMnot big enough, too small to store all programs and data needed permanently 不夠大volatile, contents lost when power is turned off 易失性Secondary Storageextension of main memory主存的擴(kuò)展big enoughnon-volatile, p

14、ermanent提供了非易失的存儲(chǔ)容量magnetic disk磁盤(pán)-覆蓋了磁記錄材料的硬金屬或玻璃盤(pán)片random accessmagnetic tapesequential accessfloppy disks, CD-ROMs, etc.data exchange (small and light, easy to carry)Moving-Head Disk Mechanism磁頭移動(dòng)機(jī)制cacheuse of high-speed memory to hold recently-accessed data使用高速存儲(chǔ)保存近期訪問(wèn)的數(shù)據(jù)cache (built into CPU)dat

15、a cacheinstruction cache, code cachecache managementlocalityabove 80% hit ratiocaching introduces another level in storage hierarchy, and it requires data that is simultaneously stored in more than one level to be consistentcoherency and consistencythe copy of a datum appears in many levels of stora

16、ge hierarchysingle process, easymultiprogramming environmentmultiprocessor environmentcache coherency, handled by hardwaredistributed environmentStorage Hierarchy存儲(chǔ)層次Caching copying information into faster storage system; main memory can be viewed as a last cache for secondary storage. 緩存- 把信息復(fù)制進(jìn)較快的

17、存儲(chǔ)系統(tǒng)；主存可看作為二級(jí)存儲(chǔ)器的最后一個(gè)緩存Hardware Protection硬件保護(hù)single-user programmer-operated system, complete control of the computer system, no protection單用戶系統(tǒng)，程序員可完全控制系統(tǒng)early OS, called resident monitor, still no protection 早期OS稱為常駐監(jiān)督程序，沒(méi)有保護(hù)batch system, need some protectione.g. an indefinite loop reading cards不

18、斷讀取卡片multiprogramming, a program may accidentally or deliberately/maliciously modify the code or data of another programHardware Protection硬件保護(hù)hardware trap to the OS, when 硬件陷入到OS當(dāng)illegal instructions, or access memory not in the address space, etc.非法指令，或訪問(wèn)不屬于自己的地址空間的內(nèi)存process terminated/aborted, c

19、ore dumped 進(jìn)程終止multi-user environment, need protection for files, data on disk/tape 多用戶環(huán)境，需要保護(hù)磁盤(pán)上的文件、數(shù)據(jù)Dual-Mode Operation 兩狀態(tài)運(yùn)行I/O Protection I/O保護(hù)Memory Protection 內(nèi)存保護(hù)CPU Protection CPU 保護(hù)Dual-Mode Operation兩狀態(tài)運(yùn)行Sharing system resources requires operating system to ensure that an incorrect progra

20、m cannot cause other programs to execute incorrectly. 共享系統(tǒng)資源要求操作系統(tǒng)確保有誤程序不會(huì)引起其他程序的運(yùn)行錯(cuò)誤Provide hardware support to differentiate between at least two modes of operations. 至少在兩個(gè)運(yùn)行狀態(tài)之間提供硬件支持1.User mode execution done on behalf of a user. 用戶態(tài)-代表用戶執(zhí)行完畢2.Monitor mode (also supervisor mode or system mode) e

21、xecution done on behalf of operating system. 管態(tài)（特權(quán)模式或系統(tǒng)模式）-代表操作系統(tǒng)執(zhí)行完畢Dual-Mode Operationmode bit added to computer hardware to indicate the current mode: monitor (0) or user (1) 模式位添加到計(jì)算機(jī)硬件，表示當(dāng)前模式mode bits in PSWwhen an interrupt or fault occurs hardware switches to monitor mode出現(xiàn)中斷或陷阱，硬件切換到管態(tài)Privil

22、eged instructions can be issued only in monitor modemonitoruserInterrupt/faultset user modeat boot time, the hardware starts in monitor mode 系統(tǒng)引導(dǎo)時(shí)，硬件處于管態(tài)starts user processes in user mode 在用戶模式下執(zhí)行用戶進(jìn)程dual-mode protect OS from errant users, and errant users from one anotherprivileged instructions:特權(quán)指

23、令 change mode, I/Oin user mode: always change mode to kernelthe way to implement system callarguments passed via registers, stack, or memory (with pointers in registers or stack)in kernel mode: just do it!I/O Protectionall I/O instructions are privileged instructions所有的I/O指令都是特權(quán)指令memory mapped I/O,

24、disk I/O (file access), display I/O, printer I/O, network I/Oa user cannot issue I/O instructions directly, he must do it through system call用戶不能直接用i/o指令，必須通過(guò)系統(tǒng)調(diào)用it must be ensured that a user program could never gain control of the computer in monitor mode確保用戶程序不能在管態(tài)下控制計(jì)算機(jī)e.g., a user program that,

25、 as part of its execution, stores a new address in the interrupt vectora way to inject a virus or Trojan horse on DOS systemUse of a system call to perform I/OMemory Protectionmust provide memory protectionat least for the interrupt vector and the interrupt service routines必須保護(hù)中斷向量和中斷服務(wù)程序in order to

26、 have memory protection, add two registers that determine the range of legal addresses a program may access確定進(jìn)程能訪問(wèn)的合法空間base register 基址寄存器 holds the smallest legal physical memory address.limit register界限寄存器 contains the size of the range memory outside the defined range is protectedMemory Protectio

27、nevery address generated in every instruction in user mode is hardware checked用戶態(tài)下所生成的每個(gè)地址都要經(jīng)過(guò)硬件檢查base and limit registers can be loaded by only the OS by using a special privileged instructionwhen executing in monitor mode, the operating system has unrestricted access to both monitor and users memo

28、rychange the (base and limit) registersload users programs into users memorydump memory map of those programs in case of errorsaccess and modify parameters of system callsCPU protectionwe must prevent a program from getting stuck in an infinite loop, or not calling OS services and never returning co

29、ntrol to the OS需防止用戶程序陷入死循環(huán)或者不調(diào)用系統(tǒng)服務(wù)且不將控制權(quán)返回到OStimer 定時(shí)器 interrupts computer after specified period to ensure operating system maintains controlfixed timer, e.g. 1/32 secondvariable timer, a fixed-rate clock and a counterthe counter is decremented every clock tickwhen the counter reaches the value 0

30、, an interrupt occursThe timerload-timer is a privileged instructionbefore turning over control to the users program, the OS ensures that the timer is set to interrupt設(shè)定計(jì)時(shí)器以便產(chǎn)生中斷if the timer interrupts, control transfers to the OS, and the user program may be killed or given more time to run定時(shí)器中斷，控制

31、權(quán)會(huì)返回給OStimer commonly used to implement time sharing用來(lái)實(shí)現(xiàn)分時(shí)系統(tǒng)time slice (every N milliseconds)timer also used to compute the current time計(jì)算當(dāng)前時(shí)間the goals of the OS must be well defined before the design beginsthree vantage pointsservices it provides提供的服務(wù)interface to users and programmers為用戶和程序提供的接口com

32、ponents and their interconnections各組成部分及其相互連接Module 3: Operating-System Structures操作系統(tǒng)結(jié)構(gòu)System Components系統(tǒng)部件Operating System Services操作系統(tǒng)服務(wù)System Calls系統(tǒng)調(diào)用System Programs系統(tǒng)程序System Structure 系統(tǒng)結(jié)構(gòu)Virtual Machines虛擬機(jī)System Design and Implementation系統(tǒng)設(shè)計(jì)和實(shí)現(xiàn)System Generation系統(tǒng)生成Common System Components系

33、統(tǒng)部件Process Management 進(jìn)程管理Main Memory Management主存管理Secondary-Storage Management 二級(jí)儲(chǔ)存器管理I/O System Management I/O系統(tǒng)管理File Management 文件管理Protection System 保護(hù)系統(tǒng)Networking 網(wǎng)絡(luò)處理Command-Interpreter System 命令解釋器系統(tǒng)Process Management進(jìn)程管理A process is a program in execution. A process needs certain resources

34、, including CPU time, memory, files, and I/O devices, to plish its task. 進(jìn)程是正在執(zhí)行的程序。為了完成其任務(wù)，進(jìn)程需要一定的資源，包括CPU時(shí)間，存儲(chǔ)器，文件，以及I/O設(shè)備The operating system is responsible for the following activities in connection with process management. 在同進(jìn)程管理有關(guān)的活動(dòng)中，操作系統(tǒng)負(fù)責(zé)下列事務(wù)：Process creation and deletion. 進(jìn)程創(chuàng)建和刪除Process su

35、spension and resumption. 進(jìn)程掛起和恢復(fù)Provision of mechanisms for 可提供以下有關(guān)機(jī)制:process synchronization 進(jìn)程同步process communication 進(jìn)程通信Providing mechanisms for deadlock handlingMain-Memory Management主存管理Memory is a large array of words or bytes, each with its own address. It is a repository of quickly accessib

36、le data shared by the CPU and I/O devices.存儲(chǔ)器是字或字節(jié)的一個(gè)大數(shù)組，每一字或字節(jié)有自己的地址。它是一個(gè)可被CPU和I/O 共享、可快速存取數(shù)據(jù)的存放地Main memory is a volatile storage device. It loses its contents in the case of system failure.主存儲(chǔ)器是一個(gè)易失性存儲(chǔ)設(shè)備。系統(tǒng)失敗時(shí)，會(huì)丟失其內(nèi)容Main-Memory Management主存管理The operating system is responsible for the following a

37、ctivities in connections with memory management: 在同存儲(chǔ)管理有關(guān)的活動(dòng)中，操作系統(tǒng)負(fù)責(zé)下列事務(wù)：Keep track of which parts of memory are currently being used and by whom. 保持記錄存儲(chǔ)器的哪一部分當(dāng)前被使用以及被誰(shuí)使用Decide which processes to load when memory space es available.當(dāng)有可用存儲(chǔ)空間時(shí)，決定調(diào)入哪個(gè)進(jìn)程Allocate and deallocate memory space as needed. 需要

38、時(shí)分配和收回存儲(chǔ)空間 Protection Secondary-Storage Management二級(jí)存儲(chǔ)管理Since main memory (primary storage) is volatile and too small to modate all data and programs permanently, the computer system must provide secondary storage to back up main memory. 由于主存（基本存儲(chǔ)器）是易失性的，而且太小不足以永久保存所有的數(shù)據(jù)和程序，計(jì)算機(jī)系統(tǒng)必須提供二級(jí)存儲(chǔ)器備份主存Most mo

39、dern computer systems use disks as the principle on-line storage medium, for both programs and data. 多數(shù)現(xiàn)代計(jì)算機(jī)系統(tǒng)采用磁盤(pán)作為程序和數(shù)據(jù)的基本聯(lián)機(jī)存儲(chǔ)介質(zhì)The operating system is responsible for the following activities in connection with disk management: 在同磁盤(pán)管理有關(guān)的活動(dòng)中，操作系統(tǒng)負(fù)責(zé)下列事務(wù)：Free space management 空閑空間管理Storage allocatio

40、n 存儲(chǔ)器分配Disk scheduling 磁盤(pán)調(diào)度I/O System Management I/O系統(tǒng)管理I/O System Management = Device managementThe I/O system consists of: I/O 系統(tǒng)包括 (Hardware and Software)A buffer-caching system 緩沖區(qū)-高速緩存系統(tǒng)A general device-driver interface 通用設(shè)備驅(qū)動(dòng)器接口Drivers for specific hardware devices 用于特定硬件設(shè)備的驅(qū)動(dòng)程序File Management

41、文件管理A file is a collection of related information defined by its creator. Commonly, files represent programs (both source and object forms) and data. 文件是由其創(chuàng)建者定義的關(guān)聯(lián)信息的一個(gè)收集器，通常文件表示程序（源程序和目標(biāo)程序）和數(shù)據(jù)The operating system is responsible for the following activities in connections with file management: 在同文件管

42、理有關(guān)的活動(dòng)中，操作系統(tǒng)負(fù)責(zé)下列事務(wù)：File creation and deletion. 文件創(chuàng)建和刪除Directory creation and deletion. 目錄創(chuàng)建和刪除Support of primitives for manipulating files and directories. 支持操作文件和目錄的原語(yǔ)Mapping files onto secondary storage. 把文件映象到二級(jí)存儲(chǔ)器File backup on stable (nonvolatile) storage media. 在穩(wěn)定（非易失性）存儲(chǔ)介質(zhì)做文件副本Protection Sys

43、tem保護(hù)系統(tǒng)Protection refers to a mechanism for controlling access by programs, processes, or users to both system and user resources. 保護(hù)是一種機(jī)制，控制程序、進(jìn)程、或用戶對(duì)系統(tǒng)和用戶資源的訪問(wèn)The protection mechanism must 保護(hù)機(jī)制必須: distinguish between authorized and unauthorized usage. 區(qū)分授權(quán)和非授權(quán)使用specify the controls to be imposed.

44、確定要采用的控制provide a means of enforcement. 提供強(qiáng)制手段Networking (Distributed Systems)網(wǎng)絡(luò)處理（分布式系統(tǒng)）A distributed system is a collection processors that do not share memory or a clock. Each processor has its own local memory. 分布式系統(tǒng)是一組不共享存儲(chǔ)器或時(shí)鐘的處理器集合，每個(gè)處理器有自己的內(nèi)存The processors in the system are connected through

45、 a communication network.系統(tǒng)中的處理器通過(guò)通信網(wǎng)絡(luò)連接A distributed system provides user access to various system resources.分布式系統(tǒng)提供用戶訪問(wèn)各種系統(tǒng)資源的手段Access to a shared resource allows:對(duì)共享資源的訪問(wèn)可以實(shí)現(xiàn)：Computation speed-up 加速運(yùn)算Increased data availability 提高數(shù)據(jù)利用性Enhanced reliability 增強(qiáng)可靠性Command-Interpreter System命令解釋器系統(tǒng)Man

46、y commands are given to the operating system by control statements which deal with: 操作系統(tǒng)有許多命令，可以通過(guò)控制語(yǔ)句處理：process creation and management 進(jìn)程創(chuàng)建和管理I/O handling 處理I/O secondary-storage management 二級(jí)存儲(chǔ)管理main-memory management 主存管理file-system access 文件訪問(wèn)protection 保護(hù)networking 網(wǎng)絡(luò)Command-Interpreter System

47、 (Cont.)命令解釋器系統(tǒng)The program that reads and interprets control statements is called variously: 讀入和解釋控制語(yǔ)句的程序有各種名稱control-card interpreter 控制卡解釋器command-line interpreter 命令行解釋器shell (in UNIX) Its function is to get and execute the next command statement. 其功能是獲得和執(zhí)行下一個(gè)命令語(yǔ)句Operating System Services操作系統(tǒng)服務(wù) f

48、or user (What can do?)User interface - Almost all operating systems have a user interface (UI)Varies between Command-Line (CLI), Graphics User Interface (GUI), BatchProgram execution system capability to load a program into memory and to run it. 程序執(zhí)行 - 調(diào)入一個(gè)程序進(jìn)內(nèi)存并運(yùn)行之的系統(tǒng)能力I/O operations since user pro

49、grams cannot execute I/O operations directly, the operating system must provide some means to perform I/O. I/O操作 - 由于用戶程序不能直接執(zhí)行I/O操作，操作系統(tǒng)必須提供手段完成I/O操作 File-system manipulation program capability to read, write, create, and delete files. 文件系統(tǒng)操作 - 讀、寫(xiě)、創(chuàng)建和刪除文件的能力Operating System Services操作系統(tǒng)服務(wù) for user

50、 (What can do?)Communications exchange of information between processes executing either on the same computer or on different systems tied together by a network. Implemented via shared memory or message passing. 通信 - 運(yùn)行的進(jìn)程在同一計(jì)算機(jī)或由網(wǎng)絡(luò)連接的不同系統(tǒng)中交換信息。通過(guò)共享存儲(chǔ)器或消息傳遞實(shí)現(xiàn)Error detection ensure correct computing

51、by detecting errors in the CPU and memory hardware, in I/O devices, or in user programs. 出錯(cuò)檢測(cè) - 探測(cè)在CPU與內(nèi)存硬件中，在I/O設(shè)備中，或在用戶程序中的錯(cuò)誤，確保正確運(yùn)算Communication ModelsMsg Passing消息傳遞Shared Memory共享內(nèi)存Additional Operating System Service其他操作系統(tǒng)服務(wù)Additional functions exist not for helping the user, but rather for ens

52、uring efficient system operations.其他的功能不是用于幫助用戶，而是為了系統(tǒng)效率：Resource allocation allocating resources to multiple users or multiple jobs running at the same time. 資源分配 - 把資源分配給多個(gè)用戶或多個(gè)同時(shí)運(yùn)行的作業(yè)Accounting keep track of and record which users use how much and what kinds of computer resources for account bill

53、ing or for accumulating usage statistics. 帳務(wù) - 跟蹤和記錄用戶對(duì)資源的使用，用于帳單和統(tǒng)計(jì)Protection ensuring that all access to system resources is controlled. 保護(hù) - 確保對(duì)資源的所有訪問(wèn)均在控制中A View of Operating System ServicesServices for the system itselfResource allocationMany types of resources - Some (such as CPU cycles, main

54、memory, and file storage) may have special allocation code, others (such as I/O devices) may have general request and release code Accounting - To keep track of which users use how much and what kinds of computer resourcesProtection and security Protection involves ensuring that all access to system

55、 resources is controlledSecurity of the system from outsiders requires user authentication, extends to defending external I/O devices from invalid access attemptsSystem Calls系統(tǒng)調(diào)用 (How to use?)System calls provide the interface between a running program and the operating system.系統(tǒng)調(diào)用提供在運(yùn)行程序和操作系統(tǒng)之間的接口G

56、enerally available as assembly-language instructions. 通常以匯編語(yǔ)言指令形式提供Languages defined to replace assembly language for systems programming allow system calls to be made directly (e.g., C. Bliss, PL/360)替代匯編語(yǔ)言的、供系統(tǒng)編程的語(yǔ)言，允許直接使用系統(tǒng)調(diào)用System Calls系統(tǒng)調(diào)用Mostly accessed by programs via a high-level Application

57、 Program Interface (API) rather than direct system call useThree most common APIs Win32 API for WindowsPOSIX API for POSIX-based systems (including virtually all versions of UNIX, Linux, and Mac OS X) Java API for the Java virtual machine (JVM)Processing of system call系統(tǒng)調(diào)用的處理機(jī)構(gòu):陷入（TRAP）或異常處理機(jī)構(gòu)把由于系統(tǒng)調(diào)

58、用引起處理機(jī)中斷的指令稱為陷入或異常指令（或稱訪管指令）Processing of system call 當(dāng)用戶使用系統(tǒng)調(diào)用時(shí)，產(chǎn)生一條相應(yīng)的指令 CPU在執(zhí)行到該指令時(shí)發(fā)生中斷，發(fā)出有關(guān)的信號(hào)給陷 入處理機(jī)構(gòu)； 處理機(jī)構(gòu)在收到了CPU發(fā)來(lái)的信號(hào)后，啟動(dòng)相關(guān)的處理程序去完成該系統(tǒng)調(diào)用所要求的功能 在處理系統(tǒng)調(diào)用之前，陷入處理機(jī)構(gòu)還需保存處理機(jī)現(xiàn)場(chǎng)（PSW、PC、系統(tǒng)調(diào)用號(hào)、用戶棧指針、通用寄存器、用戶定義的參數(shù)等）Processing of system call (cont.) 如何找到實(shí)現(xiàn)系統(tǒng)調(diào)用功能的子程序:入口地址表，每個(gè)入口地址與相應(yīng)的系統(tǒng)程序?qū)?yīng)陷入處理程序用系統(tǒng)調(diào)用功能號(hào)查找入

59、口地址表,得到該系統(tǒng)程序的入口地址,并執(zhí)行之系統(tǒng)調(diào)用處理結(jié)束后，要恢復(fù)處理機(jī)現(xiàn)場(chǎng)，從而用戶程序可以繼續(xù)執(zhí)行 system call 入口地址表 (1)保護(hù)處理機(jī)現(xiàn)場(chǎng)(2)取系統(tǒng)調(diào)用功能號(hào)并據(jù)此尋找子程序入口(3)返回A0A1Ai AnA0 A1AiAnSub0Sub1SubiSubn 用戶程序 陷入處理機(jī)構(gòu) 系統(tǒng)子程序系統(tǒng)調(diào)用的處理過(guò)程System Calls系統(tǒng)調(diào)用 (How to use?)Three general methods are used to pass parameters between a running program and the operating system.

60、 3種常用方式用于在運(yùn)行程序和操作系統(tǒng)之間的參數(shù)傳遞Pass parameters in registers. 寄存器中的參數(shù)傳遞Store the parameters in a table in memory, and the table address is passed as a parameter in a register. 參數(shù)存在內(nèi)存的一張表中，表地址 作為寄存器的參數(shù)傳遞Push (store) the parameters onto the stack by the program, and pop off the stack by operating system. 程序