四川大学：《操作系统 Operating System》课程教学资源（PPT课件讲稿）Chapter 2 Operating System Overview

Chapterol operating system overview 2.1 Operating System Objectives and Functions 2.2 The Evolution of operating systems 2.3 Major achievements 2. 4 Developments leading to modern Operating Systems

Chapter01 Operating System Overview • 2.1 Operating System Objectives and Functions • 2.2 The Evolution of Operating Systems • 2.3 Major Achievements • 2.4 Developments Leading to Modern Operating Systems 2

2.1 Operating System objectives and Functions ·2.1.0 Introduction .2 1.1 The Operating System as a User/computer Interface 2. 1.2 The Operating System as Resource Manager 2.1.3 Ease of evolution of an operating system

2.1 Operating System Objectives and Functions • 2.1.0 Introduction • 2.1.1 The Operating System as a User/Computer Interface • 2.1.2 The Operating System as Resource Manager • 2.1.3 Ease of Evolution of an Operating System 3

2.1.0 Introduction (1/2 Operating System definition: Operating systems .a program that User controls the execution of application programs, App lication acts as an interface between applications and hardware operating System Hardware

2.1.0 Introduction (1/2) • Operating System definition: • A program that • controls the execution of application programs, • acts as an interface between applications and hardware 4

2.1.0 Introduction(2/ 2 Operating System Objectives As User/Computer Interface--Convenience/F1 Makes the computer more convenient to use AS Resource manager-- Efficiency/有效 Allows computer system resources to be used in an efficient manner · AS System Software- Ability to evolve/扩展 Permit effective development, testing, and introduction of new system functions without interfering with service

2.1.0 Introduction (2/2) • Operating System Objectives • As User/Computer Interface --Convenience/方便 • Makes the computer more convenient to use • As Resource Manager--Efficiency /有效 • Allows computer system resources to be used in an efficient manner • As System Software--Ability to evolve /扩展 • Permit effective development, testing, and introduction of new system functions without interfering with service 5

2.1 Operating System objectives and Functions 2.1.0 Introduction 2.1.1 The Operating system as a User/Computer Interface 2. 1.2 The Operating System as Resource Manager 2.1.3 Ease of evolution of an operating system

2.1 Operating System Objectives and Functions • 2.1.0 Introduction • 2.1.1 The Operating System as a User/Computer Interface • 2.1.2 The Operating System as Resource Manager • 2.1.3 Ease of Evolution of an Operating System 6

2.1.1 The Operating System as a User/Computer Interface(1/ 2) Application Application programs programming interface Application Libraries/utilities Software binary interface Operating system Instruction Set Architecture Execution hardware M System interconnect translation Hardware 1/O devices Main an memory networking Figure 2. 1 Computer Hardware and Software Infrastructure

2.1.1 The Operating System as a User/Computer Interface (1/2) Figure 2.1 Computer Hardware and Software Infrastructure 7

2.1.1 The Operating System as a User/Computer Interface(2/ 2) Key interfaces Instruction set architecture(Isa) a specification of the set of opcodes(machine language) implemented by a particular processor Application binary interface(ABI interface between a library and the operating system at machine code leve Application programming interface(API) set of subroutine definitions protocols, and tools for building software and applications make it easier for developers to use certain technologies in building applications by abstracting the underlying implementation(e.g. Windows API, and Java api

2.1.1 The Operating System as a User/Computer Interface (2/2) • Key Interfaces • Instruction set architecture (ISA) • a specification of the set of opcodes (machine language) implemented by a particular processor • Application binary interface (ABI) • interface between a library and the operating system at machine code level • Application programming interface (API) • set of subroutine definitions, protocols, and tools for building software and applications. • make it easier for developers to use certain technologies in building applications by abstracting the underlying implementation (e.g. Windows API, and Java API) 8

2.1 Operating System objectives and Functions 2.1.0 Introduction .2 1.1 The Operating System as a User/computer Interface 2. 1. 2 The Operating System as resource Manager 2.1.3 Ease of evolution of an operating system

2.1 Operating System Objectives and Functions • 2.1.0 Introduction • 2.1.1 The Operating System as a User/Computer Interface • 2.1.2 The Operating System as Resource Manager • 2.1.3 Ease of Evolution of an Operating System 9

2.1.2 The Operating System as Resource Manager(173) The operating system as resource manager Responsible for managing resources/hardware Work in the same way as ordinary computer software It is program that is executed Operating system frequently relinquishes( A)and regains control of the processor

2.1.2 The Operating System as Resource Manager (1/3) • The Operating System as Resource Manager • Responsible for managing resources/Hardware • Work in the same way as ordinary computer software • It is program that is executed • Operating system frequently relinquishes(放 弃) and regains control of the processor 10

2.1.2 The Operating System as Resource Manager(2/3) App2 广空间 C library System call interface Process Memory Fil lesystem Device management management support control Networking Filesystem CPU support CPU/MMU Storage Character Network ode support code drivers device drivers device drivers

2.1.2 The Operating System as Resource Manager (2/3) 11