1 5/25/2016 操作系统课件 教材： 《操作系统概念（第六版 影印版）》 【原书名】 Operating System Concepts(Sixth Edition) [ 原书信息 ] Operating System Concepts(Sixth Edition) [ 原书信息 ] 【原出版社】 John Wiley & Sons,Incl. John Wiley & Sons,Incl. 【作者】（美） Abraham Silberschatz & Peter Baer Galvin & Greg Gagne （美） Abraham Silberschatz & Peter Baer Galvin & Greg Gagne 【丛书名】国外优秀信息科学与技术系 列教学用书 国外优秀信息科学与技术系 列教学用书 【出版社】高等教育出版社高等教育出版社 【书号】 【出版日期】

2 5/25/2016 操作系统概念（第六版 影印版）》 本书是计算机类专业操作系统课程的一本经典教材 ，自第一版问世以来，经历了近 20 年的锤炼，被认为 是该课程教材的一本 “ 圣经 ” 。它对操作系统的概念和 基本原理给出了清晰的阐述。本书所涉及的基本概念 和算法均基于当前商用操作系统，并在非特定操作系 统的通用环境中展开讲解 。书中介绍了大量与流行操 作系统相关的实现技术，包括 Solaris2 、 Linux 、 Windows NT 、 Windows 2000 、 OS/2 和 Apple Macintosh 操作系统。此版包括了线程、 Windows 2000 的新章节，并新增了客户 / 服务器模型和网络文件 系统、嵌入式操作系统、实时操作系统、分布式操作 系统等。

3 5/25/2016 教材作者的网站 l l 网站上的主要内容： l 教学参考用 Powerpoint l Java 程序源代码 l 教学内容安排的建议 l 错误订正 l 有关其他 OS 书籍的连接 l 本课件主要参考： Silberschatz, Galvin and Gagne  2002

4 5/25/2016 教材特点 l 保持 Operating System Concepts ， OSC 的原特点 l 讨论在各种操作系统中应用的基础概念 l 大量在 UNIX 和其他操作系统中的例子 : l Solaris ， Windows, NT, Linux, OS/2, AppleOS 和 Mach l 该书可以作为大学本科低年级或高年级操作系统的入门课程， l 或用作研究生第一年课程 l 在 Operating System Concepts ， OSC 第 5 版基础上，修改而成 l OSC 是一本被广泛采用的操作系统教科书 OSC 特点： l 最大特点是概念叙述清晰 l 叙述方式易读、易懂 l 前 5 版卖出 20 万本 l 随着版本的更新，不断去除旧材料，增加新材料和新例子

5 5/25/2016 Chapter 1: Introduction l What is an Operating System? l Mainframe Systems l Desktop Systems l Multiprocessor Systems l Distributed Systems l Clustered System l Real -Time Systems l Handheld Systems l Computing Environments

6 5/25/2016 What is an Operating System? l A program that acts as an intermediary between a user of a computer and the computer hardware. l Operating system goals: n Execute user programs and make solving user problems easier. n Make the computer system convenient to use. l Use the computer hardware in an efficient manner.

7 5/25/2016 Computer System Components 1.Hardware – provides basic computing resources (CPU, memory, I/O devices). 2.Operating system – controls and coordinates the use of the hardware among the various application programs for the various users. 3.Applications programs – define the ways in which the system resources are used to solve the computing problems of the users (compilers, database systems, video games, business programs). 4.Users (people, machines, other computers).

8 5/25/2016 Abstract View of System Components

9 5/25/2016 Operating System Definitions Resource allocator – manages and allocates resources. Control program – controls the execution of user programs and operations of I/O devices. Kernel – the one program running at all times (all else being application programs).

10 5/25/2016 Mainframe Systems l Reduce setup time by batching similar jobs Automatic job sequencing – automatically transfers control from one job to another. First rudimentary operating system. l Resident monitor n initial control in monitor n control transfers to job n when job completes control transfers pack to monitor

11 5/25/2016 Memory Layout for a Simple Batch System

12 5/25/2016 Multiprogrammed Batch Systems Several jobs are kept in main memory at the same time, and the CPU is multiplexed among them.

13 5/25/2016 OS Features Needed for Multiprogramming l I/O routine supplied by the system. Memory management – the system must allocate the memory to several jobs. CPU scheduling – the system must choose among several jobs ready to run. l Allocation of devices.

14 5/25/2016 Time-Sharing Systems–Interactive Computing l The CPU is multiplexed among several jobs that are kept in memory and on disk (the CPU is allocated to a job only if the job is in memory). l A job swapped in and out of memory to the disk. On-line communication between the user and the system is provided; when the operating system finishes the execution of one command, it seeks the next “ control statement ” from the user ’ s keyboard. l On-line system must be available for users to access data and code.

15 5/25/2016 Desktop Systems Personal computers – computer system dedicated to a single user. I/O devices – keyboards, mice, display screens, small printers. l User convenience and responsiveness. Can adopt technology developed for larger operating system ’ often individuals have sole use of computer and do not need advanced CPU utilization of protection features. l May run several different types of operating systems (Windows, MacOS, UNIX, Linux)

16 5/25/2016 Parallel Systems l Multiprocessor systems with more than on CPU in close communication. Tightly coupled system – processors share memory and a clock; communication usually takes place through the shared memory. l Advantages of parallel system: n Increased throughput n Economical n Increased reliability u graceful degradation u fail-soft systems

17 5/25/2016 Parallel Systems (Cont.) l Symmetric multiprocessing (SMP) n Each processor runs and identical copy of the operating system. n Many processes can run at once without performance deterioration. n Most modern operating systems support SMP l Asymmetric multiprocessing n Each processor is assigned a specific task; master processor schedules and allocated work to slave processors. n More common in extremely large systems

18 5/25/2016 Symmetric Multiprocessing Architecture

19 5/25/2016 Distributed Systems l Distribute the computation among several physical processors. Loosely coupled system – each processor has its own local memory; processors communicate with one another through various communications lines, such as high-speed buses or telephone lines. l Advantages of distributed systems. n Resources Sharing Computation speed up – load sharing n Reliability n Communications

20 5/25/2016 Distributed Systems (cont) l Requires networking infrastructure. l Local area networks (LAN) or Wide area networks (WAN) l May be either client-server or peer-to-peer systems.

21 5/25/2016 General Structure of Client-Server

22 5/25/2016 Clustered Systems l Clustering allows two or more systems to share storage. l Provides high reliability. l Asymmetric clustering: one server runs the application while other servers standby. l Symmetric clustering: all N hosts are running the application.

23 5/25/2016 Real-Time Systems l Often used as a control device in a dedicated application such as controlling scientific experiments, medical imaging systems, industrial control systems, and some display systems. l Well-defined fixed-time constraints. l Real-Time systems may be either hard or soft real- time.

24 5/25/2016 Real-Time Systems (Cont.) l Hard real-time: n Secondary storage limited or absent, data stored in short term memory, or read-only memory (ROM) n Conflicts with time-sharing systems, not supported by general-purpose operating systems. l Soft real-time n Limited utility in industrial control of robotics n Useful in applications (multimedia, virtual reality) requiring advanced operating-system features.

25 5/25/2016 Handheld Systems l Personal Digital Assistants (PDAs) l Cellular telephones l Issues: n Limited memory n Slow processors n Small display screens.

26 5/25/2016 Migration of Operating-System Concepts and Features

27 5/25/2016 Computing Environments l Traditional computing l Web-Based Computing l Embedded Computing