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