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Operating System Concepts Ku-Yaw Chang Assistant Professor, Department of Computer Science and Information Engineering Da-Yeh University.

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Presentation on theme: "Operating System Concepts Ku-Yaw Chang Assistant Professor, Department of Computer Science and Information Engineering Da-Yeh University."— Presentation transcript:

1 Operating System Concepts Ku-Yaw Chang Assistant Professor, Department of Computer Science and Information Engineering Da-Yeh University

2 2Ku-Yaw ChangChapter 1 Introduction An Operating System (OS) A program that manages the computer hardware A program that manages the computer hardware Provides a basis for application programs Provides a basis for application programs Acts as an intermediary between a user of a computer and the computer hardware Acts as an intermediary between a user of a computer and the computer hardware Some operating systems are designed to be Convenient Convenient Efficient Efficient Some combination of the above Some combination of the above

3 3Ku-Yaw ChangChapter 1 Introduction To understand how they have developed Trace the development of operating systems Trace the development of operating systems Operating system variations Operating system variations Parallel systems Real-time systems Embedded systems

4 4Ku-Yaw ChangChapter 1 Introduction 1.What is an Operating System? 2.Mainframe Systems 3.Desktop Systems 4.Multiprocessor Systems 5.Distributed Systems 6.Clustered System 7.Real-Time Systems 8.Handheld Systems 9.Feature Migration 10.Computing Environments 11.Summary 12.Exercises

5 5Ku-Yaw ChangChapter 1 Introduction 1.1 What Is an Operating System? A computer system can be divided into: The hardware The hardware The operating system The operating system The application programs The application programs The users The users

6 6Ku-Yaw ChangChapter 1 Introduction Abstract view of the components of a computer system

7 7Ku-Yaw ChangChapter 1 Introduction 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 8Ku-Yaw ChangChapter 1 Introduction Two Viewpoints User View PC Monopolize its resources Monopolize its resources Maximize the work Maximize the work Designed for ease of use - convenient Designed for ease of use - convenient Mainframe or minicomputer Terminal Terminal Share resources and may exchange information Share resources and may exchange information Maximize resource utilization – efficient Maximize resource utilization – efficientWorkstation Compromise between individual usability and resource utilization Compromise between individual usability and resource utilization Embedded computer Little or no user view Little or no user view

9 9Ku-Yaw ChangChapter 1 Introduction Two Viewpoints System View Resource allocator manages and allocates resources. manages and allocates resources. Control program controls the execution of user programs and operations of I/O devices. 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) the one program running at all times (all else being application programs)

10 10Ku-Yaw ChangChapter 1 Introduction System Goals Tradeoffs Convenience Convenience Efficiency Efficiency Operating systems have also evolved over time. Graphical User Interfaces (GUIs) Graphical User Interfaces (GUIs)

11 11Ku-Yaw ChangChapter 1 Introduction 1.What is an Operating System? 2.Mainframe Systems 3.Desktop Systems 4.Multiprocessor Systems 5.Distributed Systems 6.Clustered System 7.Real-Time Systems 8.Handheld Systems 9.Feature Migration 10.Computing Environments 11.Summary 12.Exercises

12 12Ku-Yaw ChangChapter 1 Introduction 1.2 Mainframe Systems First computers used to tackle many commercial and scientific applications Batch systems Batch systems Multiprogrammed Systems Multiprogrammed Systems Time-Sharing Systems Time-Sharing Systems

13 13Ku-Yaw ChangChapter 1 Introduction Batch Systems Early computer Physically enormous machine run from a console Physically enormous machine run from a console Input devices Input devices Card readers Tape drives User prepared a job and submitted it to the computer operator User prepared a job and submitted it to the computer operator At some time later, the output appeared. At some time later, the output appeared. Output devices Line Printer Tape drives Card punches

14 14Ku-Yaw ChangChapter 1 Introduction Batch Systems First rudimentary operating system Always resident in memory Always resident in memory To speed up processing Batch similar jobs Batch similar jobs Automatic job sequencing – transfers control from one job to another Automatic job sequencing – transfers control from one job to another Introduction of disk technology Keep all jobs on disk Keep all jobs on disk Job scheduling Job scheduling

15 15Ku-Yaw ChangChapter 1 Introduction Memory Layout for a Simple Batch System

16 16Ku-Yaw ChangChapter 1 Introduction Multiprogrammed Systems Increase CPU utilization Keep several jobs in memory simultaneously Keep several jobs in memory simultaneously CPU is multiplexed among them. CPU is multiplexed among them.

17 17Ku-Yaw ChangChapter 1 Introduction Memory Layout for a Multiprogramming System

18 18Ku-Yaw ChangChapter 1 Introduction Multiprogrammed Systems Job scheduling All the jobs enter the system are kept in the job pool All the jobs enter the system are kept in the job pool Processes residing on disk awaiting for allocation of main memory If there is not enough room for all the jobs, the system must choose among them. If there is not enough room for all the jobs, the system must choose among them. CPU scheduling If several jobs are ready to run at the same time, the system must choose among them. If several jobs are ready to run at the same time, the system must choose among them.

19 19Ku-Yaw ChangChapter 1 Introduction Time-Sharing Systems Multiprogrammed, batch systems Utilize system resources effectively Utilize system resources effectively CPU, memory, peripheral devices Do not provide user interaction with computer system. Do not provide user interaction with computer system. Time-sharing (Multitasking) system A logical extension of multiprogramming A logical extension of multiprogramming Switch CPU among multiple jobs frequently Switch CPU among multiple jobs frequently The user can interact with each program while it is running.

20 20Ku-Yaw ChangChapter 1 Introduction Time-Sharing Systems Response time The amount of time it takes to start responding (not output that response) The amount of time it takes to start responding (not output that response) An interactive (hands-on) computer system Direct communication Direct communication The response time should be short – typically with 1 second or so. The response time should be short – typically with 1 second or so.

21 21Ku-Yaw ChangChapter 1 Introduction Time-Sharing Systems A time-sharing system Allow many users to share the computer simultaneously Allow many users to share the computer simultaneously Switch rapidly from one user to the next Switch rapidly from one user to the next Give each user the impression that the entire computer system is dedicated to his/her use Give each user the impression that the entire computer system is dedicated to his/her use

22 22Ku-Yaw ChangChapter 1 Introduction Time-Sharing Systems Multiprogramming and time sharing systems are the central themes of modern operating systems Process and Thread concepts Process and Thread concepts Virtual / Physical memory Virtual / Physical memory File system File system

23 23Ku-Yaw ChangChapter 1 Introduction 1.What is an Operating System? 2.Mainframe Systems 3.Desktop Systems 4.Multiprocessor Systems 5.Distributed Systems 6.Clustered System 7.Real-Time Systems 8.Handheld Systems 9.Feature Migration 10.Computing Environments 11.Summary 12.Exercises

24 24Ku-Yaw ChangChapter 1 Introduction 1.3 Desktop Systems Personal computers (PCs) Computer system dedicated to a single user. Computer system dedicated to a single user. Appear in the 1970s Maximizing user convenience and responsiveness Maximizing user convenience and responsiveness Instead of maximizing CPU and peripheral utilization May run several different types of operating systems (Windows, MacOS, UNIX, Linux) May run several different types of operating systems (Windows, MacOS, UNIX, Linux)

25 25Ku-Yaw ChangChapter 1 Introduction 1.What is an Operating System? 2.Mainframe Systems 3.Desktop Systems 4.Multiprocessor Systems 5.Distributed Systems 6.Clustered System 7.Real-Time Systems 8.Handheld Systems 9.Feature Migration 10.Computing Environments 11.Summary 12.Exercises

26 26Ku-Yaw ChangChapter 1 Introduction 1.4 Multiprocessor Systems More than one CPU in close communication Also known as parallel systems or tightly coupled systems Also known as parallel systems or tightly coupled systems Processors share Computer bus Computer bus Clock Clock Main Advantages Increased throughput Increased throughput Economy of scale Economy of scale Increased reliability Increased reliability graceful degradation fault tolerant Memory Peripheral devices

27 27Ku-Yaw ChangChapter 1 Introduction 1.4 Multiprocessor Systems Symmetric multiprocessing (SMP) Each processor runs an identical copy of the operating system. Each processor runs an identical copy of the operating system. Many processes can run simultaneously without performance deterioration. Many processes can run simultaneously without performance deterioration. Most modern operating systems support SMP. Most modern operating systems support SMP. Asymmetric multiprocessing Each processor is assigned a specific task; master processor schedules and allocated work to slave processors. Each processor is assigned a specific task; master processor schedules and allocated work to slave processors. More common in extremely large systems More common in extremely large systems

28 28Ku-Yaw ChangChapter 1 Introduction Symmetric Multiprocessing Architecture

29 29Ku-Yaw ChangChapter 1 Introduction 1.What is an Operating System? 2.Mainframe Systems 3.Desktop Systems 4.Multiprocessor Systems 5.Distributed Systems 6.Clustered System 7.Real-Time Systems 8.Handheld Systems 9.Feature Migration 10.Computing Environments 11.Summary 12.Exercises

30 30Ku-Yaw ChangChapter 1 Introduction 1.5 Distributed Systems Depends on network functionality TCP/IP is the most common network protocol TCP/IP is the most common network protocol Local-area network (LAN) Within a room, a floor, or a building Within a room, a floor, or a building Wide-area network (WAN) Between buildings, cities, or countries Between buildings, cities, or countries Metropolitan-area network (MAN) Buildings within a city Buildings within a city Small-area network (SAN) Short distance of several feet : BlueTooth Short distance of several feet : BlueTooth

31 31Ku-Yaw ChangChapter 1 Introduction Client-Server Systems Centralized systems Terminals Terminals Supplanted by PCs Server systems Server systems Satisfy requests generated by client systems Two categories (broadly) Compute-server systems Compute-server systems File-server systems File-server systems

32 32Ku-Yaw ChangChapter 1 Introduction General Structure of a Client-Server System

33 33Ku-Yaw ChangChapter 1 Introduction Peer-to-Peer Systems Distribute the computation among several physical processors. Loosely coupled system each processor has its own local memory each processor has its own local memory processors communicate with one another through various communications lines, such as high-speed buses or telephone lines. processors communicate with one another through various communications lines, such as high-speed buses or telephone lines. Network operating system Provide features such as file sharing across the network Provide features such as file sharing across the network

34 34Ku-Yaw ChangChapter 1 Introduction 1.What is an Operating System? 2.Mainframe Systems 3.Desktop Systems 4.Multiprocessor Systems 5.Distributed Systems 6.Clustered System 7.Real-Time Systems 8.Handheld Systems 9.Feature Migration 10.Computing Environments 11.Summary 12.Exercises

35 35Ku-Yaw ChangChapter 1 Introduction 1.6 Clustered Systems Gather multiple CPUs to accomplish computational work Provide high availability Provide high availability General accepted definition Clustered computers share storage and are closely linked via LAN networking Clustered computers share storage and are closely linked via LAN networking

36 36Ku-Yaw ChangChapter 1 Introduction 1.6 Clustered Systems Asymmetric clustering one server runs the application while other servers standby. one server runs the application while other servers standby. Symmetric clustering all N hosts are running the application. all N hosts are running the application.

37 37Ku-Yaw ChangChapter 1 Introduction 1.6 Clustered Systems Parallel clusters Multiple hosts to access the same data on the shared storage Multiple hosts to access the same data on the shared storage Most OSs lack such support Clustering over a WAN Global clusters – the machines could be anywhere in the world Global clusters – the machines could be anywhere in the world Cluster technology is rapidly changing. Storage-Area-Networks (SANs) Storage-Area-Networks (SANs)

38 38Ku-Yaw ChangChapter 1 Introduction 1.What is an Operating System? 2.Mainframe Systems 3.Desktop Systems 4.Multiprocessor Systems 5.Distributed Systems 6.Clustered System 7.Real-Time Systems 8.Handheld Systems 9.Feature Migration 10.Computing Environments 11.Summary 12.Exercises

39 39Ku-Yaw ChangChapter 1 Introduction 1.7 Real-Time Systems Well-defined, fixed time constraints Processing must be done within the defined constraints, or the system will fail. Processing must be done within the defined constraints, or the system will fail. Often used as a control device in a dedicated application Weapon systems Weapon systems Medical imaging systems Medical imaging systems Industrial control systems Industrial control systems

40 40Ku-Yaw ChangChapter 1 Introduction Two Flavors Hard real-time system Secondary storage limited or absent, data stored in short term memory, or read-only memory (ROM) 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 Conflicts with time-sharing systems, not supported by general-purpose operating systems Soft real-time system Limited utility in industrial control of robotics Limited utility in industrial control of robotics Useful in applications (multimedia, virtual reality) requiring advanced operating-system features Useful in applications (multimedia, virtual reality) requiring advanced operating-system features

41 41Ku-Yaw ChangChapter 1 Introduction 1.What is an Operating System? 2.Mainframe Systems 3.Desktop Systems 4.Multiprocessor Systems 5.Distributed Systems 6.Clustered System 7.Real-Time Systems 8.Handheld Systems 9.Feature Migration 10.Computing Environments 11.Summary 12.Exercises

42 42Ku-Yaw ChangChapter 1 Introduction 1.8 Handheld Systems Personal Digital Assistants (PDAs) Palm Palm Cellular telephones Limited size Small amount of memory Small amount of memory Slow processor Slow processor Small display screens Small display screens

43 43Ku-Yaw ChangChapter 1 Introduction 1.What is an Operating System? 2.Mainframe Systems 3.Desktop Systems 4.Multiprocessor Systems 5.Distributed Systems 6.Clustered System 7.Real-Time Systems 8.Handheld Systems 9.Feature Migration 10.Computing Environments 11.Summary 12.Exercises

44 44Ku-Yaw ChangChapter 1 Introduction Migration of OS Concepts and Features

45 45Ku-Yaw ChangChapter 1 Introduction 1.What is an Operating System? 2.Mainframe Systems 3.Desktop Systems 4.Multiprocessor Systems 5.Distributed Systems 6.Clustered System 7.Real-Time Systems 8.Handheld Systems 9.Feature Migration 10.Computing Environments 11.Summary 12.Exercises

46 46Ku-Yaw ChangChapter 1 Introduction 1.10 Computing Environments Traditional computing Web-based computing Embedded computing

47 47Ku-Yaw ChangChapter 1 Introduction 1.What is an Operating System? 2.Mainframe Systems 3.Desktop Systems 4.Multiprocessor Systems 5.Distributed Systems 6.Clustered System 7.Real-Time Systems 8.Handheld Systems 9.Feature Migration 10.Computing Environments 11.Summary 12.Exercises

48 48Ku-Yaw ChangChapter 1 Introduction Summary P.23 – P.24

49 49Ku-Yaw ChangChapter 1 Introduction 1.What is an Operating System? 2.Mainframe Systems 3.Desktop Systems 4.Multiprocessor Systems 5.Distributed Systems 6.Clustered System 7.Real-Time Systems 8.Handheld Systems 9.Feature Migration 10.Computing Environments 11.Summary 12.Exercises

50 50Ku-Yaw ChangChapter 1 Introduction Exercises

51 The End


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