December 11, 2019
Amitraj
Process Control Block (PCB)
A process control block is a data structure maintained by the operating system for every process. The PCB is identified by an integer process ID (PID). A PCB keeps all the information needed to keep track of a process as listed below:-
Structure of control block
1. Process state
The current state of the process i.e. whether it is ready, running, waiting or whatever.
2. Process privillege
This is required to allow/disallow access to system resources.
3. Process ID
unique identification for each of the process in the OS.
4. Pointer
A pointer to parent process.
5. Program counter
program counter is a pointer to the address to the next instruction to be executed for this process.
6. CPU Register
Various CPU registers where process need to be stored for execution for running state.
7. CPU scheduling info
process priority and other scheduling information which is required to schedule the process.
8. Memory Management Information
The memory management information includes the page tables or the segment tables depending on the memory system used. It also contains the value of the base registers, limit registers etc.
9. Accounting information
The time limits, account numbers, amount of CPU used, process numbers etc. are all a part of the PCB accounting information.
10. I/O Status Information
This information includes the list of I/O devices used by the process, the list of files etc.
A process control block is a data structure maintained by the operating system for every process. The PCB is identified by an integer process ID (PID). A PCB keeps all the information needed to keep track of a process as listed below:-
Structure of control block
1. Process state
The current state of the process i.e. whether it is ready, running, waiting or whatever.
2. Process privillege
This is required to allow/disallow access to system resources.
3. Process ID
unique identification for each of the process in the OS.
4. Pointer
A pointer to parent process.
5. Program counter
program counter is a pointer to the address to the next instruction to be executed for this process.
6. CPU Register
Various CPU registers where process need to be stored for execution for running state.
7. CPU scheduling info
process priority and other scheduling information which is required to schedule the process.
8. Memory Management Information
The memory management information includes the page tables or the segment tables depending on the memory system used. It also contains the value of the base registers, limit registers etc.
9. Accounting information
The time limits, account numbers, amount of CPU used, process numbers etc. are all a part of the PCB accounting information.
10. I/O Status Information
This information includes the list of I/O devices used by the process, the list of files etc.
