Process Control Block (PCB) - cook the code

Monday, 25 December 2017

Process Control Block (PCB)

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 in the table −
S.N.Information & Description
1
Process State
The current state of the process i.e.,
whether it is ready, running, waiting,
or whatever.
2
Process privileges
This is required to allow/disallow
access to system resources.
3
Process ID
Unique identification for each of
the process in the operating system.
4
Pointer
A pointer to parent process.
5
Program Counter
Program Counter is a pointer to
the address of the next instruction
 to be executed for this process.
6
CPU registers
Various CPU registers where
process need to be stored for execution
for running state.
7
CPU Scheduling Information
Process priority and other scheduling
 information which is required to schedule the process.
8
Memory management information
This includes the information of page table, memory limits, Segment table depending on memory used by the operating system.
9
Accounting information
This includes the amount of CPU used for process execution, time limits, execution ID etc.
10
IO status information
This includes a list of I/O devices allocated to the process.
The architecture of a PCB is completely dependent on Operating System and may contain different information in different operating systems. Here is a simplified diagram of a PCB −
Process Control Block
The PCB is maintained for a process throughout its lifetime, and is deleted once the process terminates.

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