tailieunhanh - Lecture Operating systems: A concept-based approach (2/e): Chapter 1 - Dhananjay M. Dhamdhere

Chapter 1 - Introduction. In this chapter, the following content will be discussed: Overview of operating systems, OS and the computer system, memory utilization during operation of an OS, the program status word (PSW), privileged mode of CPU, state of the CPU,. | PROPRIETARY MATERIAL. © 2007 The McGraw-Hill Companies, Inc. All rights reserved. No part of this PowerPoint slide may be displayed, reproduced or distributed in any form or by any means, without the prior written permission of the publisher, or used beyond the limited distribution to teachers and educators permitted by McGraw-Hill for their individual course preparation. If you are a student using this PowerPoint slide, you are using it without permission. What is an operating system ? An operating system (OS) is a collection of programs that achieve effective utilization of a computer system by providing Convenient methods of using a computer Saves users’ time and boosts their productivity Efficient use of the computer An OS has several kinds of users The OS meets diverse requirements of different kinds of users Each user has a different view of what an OS is, and what it does. Each of these views is called an abstract view Abstract views An abstract view focuses on the essential . | PROPRIETARY MATERIAL. © 2007 The McGraw-Hill Companies, Inc. All rights reserved. No part of this PowerPoint slide may be displayed, reproduced or distributed in any form or by any means, without the prior written permission of the publisher, or used beyond the limited distribution to teachers and educators permitted by McGraw-Hill for their individual course preparation. If you are a student using this PowerPoint slide, you are using it without permission. What is an operating system ? An operating system (OS) is a collection of programs that achieve effective utilization of a computer system by providing Convenient methods of using a computer Saves users’ time and boosts their productivity Efficient use of the computer An OS has several kinds of users The OS meets diverse requirements of different kinds of users Each user has a different view of what an OS is, and what it does. Each of these views is called an abstract view Abstract views An abstract view focuses on the essential characteristics of a system It contains some selected characteristics, and ignores others It helps to control complexity in designing and understanding a system, by hiding unnecessary detail For example, two abstract views of a car: The driver’s view contains the rear-view mirror, steering, gear shift, and speedometer but ignores engine details The mechanic’s view contains fluid levels, electrical system, Q: Give examples of abstract views A: View of an abstract data type, object, Abstract views Abstract views are used in Software requirements specification Specify what functions a system should perform The abstract view of a specific function helps in understanding the system data and fundamental operations on them Software design and implementation ‘Hiding’ the details of functions and subsystems while designing or implementing other functions and subsystems helps to control complexity A designer’s abstract view of an OS User interface: Accepts commands from users: GUI, command .