四川大学：《操作系统 Operating System》课程教学资源（PPT课件讲稿）Chapter 3 Process Description and Control 3.1 What is a Process 3.2 Process States 3.3 Process Description

Chap3 Process Description and Control ·3.1 What is a process 3.2 Process states 3.3 Process description ·3.4 Process contro 3.5 Execution of the Operating System

2 Chap3 Process Description and Control • 3.1 What is a Process • 3.2 Process States • 3.3 Process Description • 3.4 Process Control • 3.5 Execution of the Operating System

3. 1 What is a process .3 1.1 Background 3.1.2 Processes and pcbs

3.1 What is a Process • 3.1.1 Background • 3.1.2 Processes and PCBs *

3.1.1 Background(1/1) Requirements of an Operating System Interleave(交替) the execution of multiple jobs/tasks/iE/programs/processes to maximize processor utilization while providing reasonable response time(响应 时间) Allocate resources to processes Support interprocess communication(进程 间通信) and user creation of processes

3.1.1 Background(1/1) • Requirements of an Operating System • Interleave(交替) the execution of multiple jobs/tasks/道/programs/processes to • maximize processor utilization • while providing reasonable response time(响应 时间) • Allocate resources to processes • Support interprocess communication(进程 间通信) and user creation of processes 4

3. 1 What is a process ·3.1.1 Background 3.1.2 Processes and Pcbs

3.1 What is a Process • 3.1.1 Background • 3.1.2 Processes and PCBs 5

3. 1.2 Processes and PcBs(1/4) .a program in execution An instance of a program running on a computer The entity that can be assigned to and executed on a processor A unit of activity characterized by he execution of a sequence of instructions · a current state an associated set of system resources

3.1.2 Processes and PCBs(1/4) • A program in execution • An instance of a program running on a computer • The entity that can be assigned to and executed on a processor • A unit of activity characterized by： • the execution of a sequence of instructions • a current state • an associated set of system resources • ...... 6

3. 1.2 Processes and PCBs(2/4) ( Review) Process构成: Consists of three components An executable program /code Associated data needed by the program Execution context of the program(the core All information the operating system needs to manage the process Hardware Software

3.1.2 Processes and PCBs(2/4) • (Review) Process构成：Consists of three components • An executable program /code • Associated data needed by the program • Execution context of the program (the core) • All information the operating system needs to manage the process • Hardware • Software 7

3. 1.2 Processes and PcBs( 3/4) Process elements Identifier Identifier State Priority State Program counter Priority Memory Pointers Program counter Context Data yO Status Memory pointers Information Context data Accounting Information I/o status information Accounting information

3.1.2 Processes and PCBs(3/4) • Process Elements • Identifier • State • Priority • Program counter • Memory pointers • Context data • I/O status information • Accounting information 8

3. 1.2 Processes and PcBs(4/ 4) Process control block(进程控制块PCB) Contains the process elements Created and manage by the operating system Allows support for multiple processes

3.1.2 Processes and PCBs(4/4) • Process Control Block(进程控制块 PCB) • Contains the process elements • Created and manage by the operating system • Allows support for multiple processes 9

Chap3 Process description and control ·3.1 What is a process 3.2 Process states 3.3 Process description ·3.4 Process contro 3.5 Execution of the Operating System

10 Chap3 Process Description and Control • 3.1 What is a Process • 3.2 Process States • 3.3 Process Description • 3.4 Process Control • 3.5 Execution of the Operating System

3.2 Process states .3.2.1 Trace of the process 3.2.2 A TWo-State Process model 3.2.3 The Creation and termination of Processes 3.2, 4A Five-State Model 3.2.5 Suspended process

11 3.2 Process States • 3.2.1 Trace of the Process • 3.2.2 A Two-State Process Model • 3.2.3 The Creation and Termination of Processes • 3.2.4 A Five-State Model • 3.2.5 Suspended Process