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] 【原出版社】John Wiley & Sons,Incl.   【作者】（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   【出版社】高等教育出版社 【书号】7-04-011048-2  【出版日期】2002-5-1 1 4/16/2019

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。 2 4/16/2019

教材作者的网站 http://www.bell-labs.com/topic/books/aos-book 网站上的主要内容： 教学参考用PowerPoint Java 程序源代码 教学内容安排的建议 错误订正 有关其他OS 书籍的连接 本课件主要参考：Silberschatz, Galvin and Gagne 2002 3 4/16/2019

教材特点 保持Operating System Concepts，OSC的原特点 讨论在各种操作系统中应用的基础概念 大量在UNIX和其他操作系统中的例子: Solaris，Windows, NT, Linux, OS/2, AppleOS 和Mach 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， 或用作研究生第一年课程 在Operating System Concepts，OSC第5版基础上，修改而成 OSC是一本被广泛采用的操作系统教科书OSC特点： 最大特点是概念叙述清晰 叙述方式易读、易懂 前5版卖出20万本 随着版本的更新，不断去除旧材料，增加新材料和新例子 4 4/16/2019

Chapter 1: Introduction What is an Operating System? Mainframe Systems Desktop Systems Multiprocessor Systems Distributed Systems Clustered System Real -Time Systems Handheld Systems Computing Environments 5 4/16/2019

What is an Operating System? A program that acts as an intermediary between a user of a computer and the computer hardware. Operating system goals: Execute user programs and make solving user problems easier. Make the computer system convenient to use. Use the computer hardware in an efficient manner. 6 4/16/2019

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). 7 4/16/2019

Abstract View of System Components 8 4/16/2019

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). 9 4/16/2019

Mainframe Systems Reduce setup time by batching similar jobs Automatic job sequencing – automatically transfers control from one job to another. First rudimentary operating system. Resident monitor initial control in monitor control transfers to job when job completes control transfers pack to monitor 10 4/16/2019

Memory Layout for a Simple Batch System 11 4/16/2019

Multiprogrammed Batch Systems Several jobs are kept in main memory at the same time, and the CPU is multiplexed among them. 12 4/16/2019

OS Features Needed for Multiprogramming 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. Allocation of devices. 13 4/16/2019

Time-Sharing Systems–Interactive Computing 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). 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. On-line system must be available for users to access data and code. 14 4/16/2019

Desktop Systems Personal computers – computer system dedicated to a single user. I/O devices – keyboards, mice, display screens, small printers. 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. May run several different types of operating systems (Windows, MacOS, UNIX, Linux) 15 4/16/2019

Parallel Systems 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. Advantages of parallel system: Increased throughput Economical Increased reliability graceful degradation fail-soft systems 16 4/16/2019

Parallel Systems (Cont.) Symmetric multiprocessing (SMP) Each processor runs and identical copy of the operating system. Many processes can run at once without performance deterioration. Most modern operating systems support SMP Asymmetric multiprocessing Each processor is assigned a specific task; master processor schedules and allocated work to slave processors. More common in extremely large systems 17 4/16/2019

Symmetric Multiprocessing Architecture 18 4/16/2019

Distributed Systems 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. Advantages of distributed systems. Resources Sharing Computation speed up – load sharing Reliability Communications 19 4/16/2019

Distributed Systems (cont) Requires networking infrastructure. Local area networks (LAN) or Wide area networks (WAN) May be either client-server or peer-to-peer systems. 20 4/16/2019

General Structure of Client-Server 21 4/16/2019

Clustered Systems Clustering allows two or more systems to share storage. Provides high reliability. Asymmetric clustering: one server runs the application while other servers standby. Symmetric clustering: all N hosts are running the application. 22 4/16/2019

Real-Time Systems 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. Well-defined fixed-time constraints. Real-Time systems may be either hard or soft real-time. 23 4/16/2019

Real-Time Systems (Cont.) Hard real-time: Secondary storage limited or absent, data stored in short term memory, or read-only memory (ROM) Conflicts with time-sharing systems, not supported by general-purpose operating systems. Soft real-time Limited utility in industrial control of robotics Useful in applications (multimedia, virtual reality) requiring advanced operating-system features. 24 4/16/2019

Handheld Systems Personal Digital Assistants (PDAs) Cellular telephones Issues: Limited memory Slow processors Small display screens. 25 4/16/2019

Migration of Operating-System Concepts and Features 26 4/16/2019

Computing Environments Traditional computing Web-Based Computing Embedded Computing 27 4/16/2019