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 3.6 Unix SVR4 Process Management 3.7 Linux Process management system calls
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 • 3.6 Unix SVR4 Process Management • 3.7 Linux Process management system calls 2
3. 4 Process Control 3. 4.1 Modes of execution 3.4.2 Process creation 3.4.3 Process Switching
3.4 Process Control • 3.4.1 Modes of Execution • 3.4.2 Process Creation • 3.4.3 Process Switching 3
3.4.1 Modes of Execution(1/ 1) User mode Less-privileged mode User programs typically execute in this mode System mode, control mode, or kernel mode More-privileged mode Kernel of the operating system Translation between the two model Processor status register(psr) and current privileged level(cpl User mode-> System mode System mode->User mode
3.4.1 Modes of Execution(1/1) • User mode • Less-privileged mode • User programs typically execute in this mode • System mode, control mode, or kernel mode • More-privileged mode • Kernel of the operating system • Translation between the two model • Processor status register (psr) and current privileged level (cpl) • User mode->System mode • System mode->User mode 4
3. 4 Process Control 3. 4.1 Modes of execution 3.4.2 Process creation 3.4.3 Process Switching 3.4.4 Execution of the Operating System
3.4 Process Control • 3.4.1 Modes of Execution • 3.4.2 Process Creation • 3.4.3 Process Switching • 3.4.4 Execution of the Operating System 5
3.4.2 Process Creation( 1/3) Assign a unique process identifier Allocate space for the process Initialize process control block Set up appropriate linkages Ex:add new process to linked list used for scheduling queue Create of expand other data structures Ex: maintain an accounting file
3.4.2 Process Creation（1/3） • Assign a unique process identifier • Allocate space for the process • Initialize process control block • Set up appropriate linkages • Ex: add new process to linked list used for scheduling queue • Create of expand other data structures • Ex: maintain an accounting file 6