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Welcome! Operating System Concepts 6th Edition Abraham Silberschatz Peter Baer Galvin Greg Gagne [email protected] Operating System Concepts 1.1 Chapter one Operating System Course Overview 1. Overview of computer system and OS 2. Concept, principle,method, algorithm, technology about how OS manages system resources and provides services for users. 3. Case study: linux, Windows 2000, Free BSD, Solaris, etc. 4. Practice of linux: source code analyzing programming Operating System Concepts 1.2 Chapter one References: 1.操作系统内核与设计原理(Operating System Internals and Design Principles), William Stalling, 第四版,电子 工业出版社,2002 2. 边干边学:Linux内核学习指导,浙江大学出版社 3. Linux Kernel Internals,2nd Edition 4.操作系统学习指导与考试指导,在杭高校教师合编,浙江 大学出版社,2004 Operating System Concepts 1.3 Chapter one Evaluation Assignments (in English) Mid-term Exam (in English, if required) Final Exam: (all in English) Operating System Concepts 1.4 Chapter one Assignments The assignments will be: Exercises on theory covered in class Better if in English Labs Familiar with the linux OS environment Reading and analyzing of linux source codes, including important data structure,etc. Exercises on programming in linux environment, including system calls, etc. Prerequisites C Programming skills Course on Computer Organization Operating System Concepts 1.5 Chapter one OS Concept Course content (if time permits...) Introduction Operating system overview. Process. Threads. Concurrency: mutual exclusion and synchronization. Concurrency: deadlock and starvation. Processor scheduling. Memory management. Virtual memory. I/O management and disk scheduling. File management. Operating System Concepts 1.6 Chapter one Chapter 1: Introduction What is an Operating System? Mainframe Systems Desktop Systems Multiprocessor Systems Distributed Systems Clustered Systems Real -Time Systems Embedded Systems Computing Environments Operating System Concepts 1.7 Chapter one 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.(e.g. multi-threaded server) Make the computer system convenient to use.(e.g. GUI) Use the computer hardware in an efficient manner. Operating System Concepts 1.8 Chapter one 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). Operating System Concepts 1.9 Chapter one Abstract View of System Components Operating System Concepts 1.10 Chapter one 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). Operating System Concepts 1.11 Chapter one Mainframe Systems Reduce setup time by batching similar jobs Automatic job sequencing – automatically transfers control from one job to another. First rudimentary operating system. (Simple Batch System:简单批处理系统) Resident monitor(常驻内存的监控程序) initial control in monitor control transfers to job when job completes control transfers back to monitor Operating System Concepts 1.12 Chapter one Memory Layout for a Simple Batch System Operating System Concepts 1.13 Chapter one Multiprogrammed Batch Systems (多道程序批处理系统) Several jobs are kept in main memory at the same time, and the CPU is multiplexed among them. Operating System Concepts 1.14 Chapter one 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. Operating System Concepts 1.15 Chapter one 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. Operating System Concepts 1.16 Chapter one 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 systems, 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) Operating System Concepts 1.17 Chapter one Parallel Systems Multiprocessor systems with more than one CPU in close communication. Tightly coupled system – processors share memory and a clock; communication usually takes place through the shared memory.(紧耦合系 统) Advantages of parallel system: Increased throughput Economy of scale Increased reliability graceful degradation(fault tolerant) fail-soft systems Operating System Concepts 1.18 Chapter one Parallel Systems (Cont.) Symmetric multiprocessing (SMP) Each processor runs an 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 allocates work to slave processors. More common in extremely large systems Operating System Concepts 1.19 Chapter one Symmetric Multiprocessing Architecture Operating System Concepts 1.20 Chapter one 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.(松耦合系统) Advantages of distributed systems. Resources Sharing Computation speed up – load sharing Reliability Communications Operating System Concepts 1.21 Chapter one 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. Operating System Concepts 1.22 Chapter one General Structure of Client-Server Operating System Concepts 1.23 Chapter one Clustered Systems(群集系统) 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. Operating System Concepts 1.24 Chapter one Real-Time Systems(实时系统) 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. E.g. VxWorks Well-defined fixed-time constraints. System design aims at satifying as many timeconstraint processings as possible, not the overall throughput or response time Real-Time systems may be either hard or soft real-time.(硬实时系统、软实时系统) Operating System Concepts 1.25 Chapter one 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 or robotics Useful in applications (multimedia, virtual reality) requiring advanced operating-system features. Operating System Concepts 1.26 Chapter one Embedded Systems(嵌入式系统) Personal Digital Assistants (PDAs:个人数字助理) Cellular telephones(蜂窝电话) IP phones Digitized appliances features: Limited memory Slow processors Small display screens Real-time requirements(maybe) Operating System Concepts 1.27 Chapter one Migration of Operating-System Concepts and Features Operating System Concepts 1.28 Chapter one Computing Environments Traditional computing Web-Based Computing Embedded Computing Operating System Concepts 1.29 Chapter one