西安电子科技大学：《操作系统 Operating Systems》课程教学资源（PPT课件讲稿）Chapter 01 Introduction（主讲：高海昌）

Operating Systems Chapter 1: Introduction 1 What is an operating system(定义) 12 History of operating systems(历史) 13 The operating system z00(分类) 14 Computer hardware review(底层硬件) 1 Operating system concepts(概念) n1 System calls(系统调用) 17 Operating system structure(结构) Gao Haichang, Software School, Xidian University

Operating Systems Gao Haichang , Software School, Xidian University 4 Chapter 1: Introduction  1.1 What is an operating system (定义)  1.2 History of operating systems (历史)  1.3 The operating system zoo (分类）  1.4 Computer hardware review（底层硬件）  1.5 Operating system concepts（ 概念）  1.6 System calls（系统调用）  1.7 Operating system structure （结构）

Operating Systems 1.1 Definition Banking Airline system reservationbrowser Application programs Command Compilers Editors interpreter Syste programs Operating system Machine language Microarchitecture Hardware Physical devices G A computer system consists of 口 Hardware A system programs H application programs Gao Haichang, Software School, Xidian University

Operating Systems Gao Haichang , Software School, Xidian University 5 1.1 Definition  A computer system consists of  Hardware  system programs  application programs

Operating Systems Abstract view of System Components user user user user n compiler assembler text editor database system system and application programs lting system computer hardware Gao Haichang, Software School, Xidian University

Operating Systems Gao Haichang , Software School, Xidian University 6 Abstract View of System Components

Operating Systems Layers of Computer System End User Application Programs OperatIn Utiliti Operating System Computer Hardware Layers and views of a Computer system Gao Haichang, Software School, Xidian University

Operating Systems Gao Haichang , Software School, Xidian University 7 Layers of Computer System Layers and Views of a Computer System

What is an Operating System p opend ing Systems g It is an extended machine top-down view H Hides the messy details which must be performed H Presents user with a virtual machine. easier to use g It is a resource manager bottom-up view m Each program gets time with the resource e.g. Multiple programs run on one CPU H Each program gets space on the resource e.g. main memory is divided up among several running programs Gao Haichang, Software School, Xidian University

Operating Systems Gao Haichang , Software School, Xidian University 8 What is an Operating System?  It is an extended machine top-down view  Hides the messy details which must be performed.  Presents user with a virtual machine, easier to use.  It is a resource manager bottom-up view  Each program gets time with the resource e.g. Multiple programs run on one CPU.  Each program gets space on the resource e.g. Main memory is divided up among several running programs

Operating Systems What is an Operating System? (2) G a program that acts as an intermediary between a user of a computer and the computer hardware Operating system goals: A Execute user programs and make solving user problems easier w Make the computer system convenient to use t Use the computer hardware in an efficient manner a Permit effective development, testing, and introduction of new system functions without interfering with service.(易于扩充) Gao Haichang, Software School, Xidian University

Operating Systems Gao Haichang , Software School, Xidian University 9 What is an Operating System?(2)  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.  Make the computer system convenient to use.  Use the computer hardware in an efficient manner.  Permit effective development, testing, and introduction of new system functions without interfering with service. （易于扩充）

Operating Systems Operating System Definitions e Resource allocator- manages and allocates resources G Control program -controls the execution of user programs and operations of l/o devices G Kernel- the one program running at all times(all else being application programs). Gao Haichang, Software School, Xidian University 10

Operating Systems Gao Haichang , Software School, Xidian University 10 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 Systems 1.2 History of Operating Systems G First generation 1945-1955 H vacuum tubes, plug boards(真空管,穿孔卡) Second generation 1955-1965 A transistors, batch systems(晶体管,批处理) Third generation 1965-1980 H ICs and multiprogramming(集成电路,多道) G Fourth generation 1980-present personal computers(个人电脑) Gao Haichang, Software School, Xidian University

Operating Systems Gao Haichang , Software School, Xidian University 11 1.2 History of Operating Systems First generation 1945 - 1955  vacuum tubes, plug boards(真空管，穿孔卡) Second generation 1955 - 1965  transistors, batch systems（晶体管，批处理） Third generation 1965 – 1980  ICs and multiprogramming（集成电路，多道） Fourth generation 1980 – present  personal computers（个人电脑）

Operating Systems History of Operating Systems (1) Ta Syste drive Input tape Output Card reader Printer 1401 7094 1401 (f) early batch system a bring cards to 1401 E read cards to tape r put tape on 7094 which does computing H put tape on 140 1 which prints output Gao Haichang, Software School, Xidian University 12

Operating Systems Gao Haichang , Software School, Xidian University 12 History of Operating Systems (1) Early batch system  bring cards to 1401  read cards to tape  put tape on 7094 which does computing  put tape on 1401 which prints output

Operating Systems History of Operating Systems(2) b 2 M emo Job 1 partitions Operating system Multiprogramming system H three jobs in memory -3ra generation Gao Haichang, Software School, Xidian University 13

Operating Systems Gao Haichang , Software School, Xidian University 13 History of Operating Systems (2) Multiprogramming system  three jobs in memory – 3 rd generation