tailieunhanh - Lecture Operating systems: A concept-based approach: Chapter 1 - Dhananjay M. Dhamdhere

This chapter discusses how users perceive user convenience, how an operating system achieves efficient use of resources, and how it ensures security and protection. It introduces the notion of effective utilization of a computer system as the combination of user convenience and efficient use that best suits a specific computing environment. It also describes the fundamental tasks involved in management of programs and resources, and in implementing security and protection. | Chapter 1 Introduction Copyright © 2008 Introduction Abstract Views of an Operating System Goals of an OS Operation of an OS Preview of the Book 1. Operating Systems, by Dhananjay Dhamdhere Copyright © 2008 Abstract Views of an Operating System What is an OS? Abstract views To a college student: SW that permits access to the Internet To a programmer: SW that makes it possible to develop programs on a computer system To a user of an application package: SW that makes it possible to use the package To a technician in a computerized chemical plant: invisible component of a computer system that controls the plant An abstract view focuses only on essential characteristics 1. Operating Systems, by Dhananjay Dhamdhere Copyright © 2008 Abstract Views of an Operating System (continued) Operating system designer also has an abstract view OS is a collection of routines that facilitates execution of user programs and use of resources 1. Operating Systems, by Dhananjay Dhamdhere . | Chapter 1 Introduction Copyright © 2008 Introduction Abstract Views of an Operating System Goals of an OS Operation of an OS Preview of the Book 1. Operating Systems, by Dhananjay Dhamdhere Copyright © 2008 Abstract Views of an Operating System What is an OS? Abstract views To a college student: SW that permits access to the Internet To a programmer: SW that makes it possible to develop programs on a computer system To a user of an application package: SW that makes it possible to use the package To a technician in a computerized chemical plant: invisible component of a computer system that controls the plant An abstract view focuses only on essential characteristics 1. Operating Systems, by Dhananjay Dhamdhere Copyright © 2008 Abstract Views of an Operating System (continued) Operating system designer also has an abstract view OS is a collection of routines that facilitates execution of user programs and use of resources 1. Operating Systems, by Dhananjay Dhamdhere Copyright © 2008 Abstract views We use abstract views to present design of OS components. It has two benefits: Managing complexity Abstract view contains only selected features of a system Presenting a generic view For example, user interface of Figure has many variants in practice Command line interface Graphical user interface (GUI) 1. Operating Systems, by Dhananjay Dhamdhere Copyright © 2008 Goals of an OS Fundamental goals of an operating system Efficient use of computer resources User convenience Noninterference in the activities of its users When these goals conflict, designer makes a trade-off for Efficient use User convenience Notion of effective utilization Each OS provides a different flavor of effectiveness 1. Operating Systems, by Dhananjay Dhamdhere Copyright © 2008 Efficient Use OS ensures efficient use of memory, CPU, and I/O devices Poor efficiency can result if a program does not use a resource allocated to it OS itself consumes CPU and memory resources, which .