Explain role of process control block?

Subject: Operating System

Topic: Process Concept and Scheduling

Difficulty: High

1 Answer

Role of process control block

  • At any instance, a process will be having various information associated with it like identifier, state, priority, program counters, memory pointers, accounting information etc. Such information are stored in a data structure called as Process Control block (PCB).
  • It is an important tool that helps the OS support multiple processes and provide for multiprocessing.
  • It contains sufficient information such that if an interrupt occurs, the process can begin from the point where it left later as if nothing had happened.
  • The blocks are read and/or modified by every module in the OS including
    • Scheduling
    • Resource allocation
    • Interrupt processing
    • Performance monitoring and analysis
  • It can be said that the process control block defines the state of OS.
  • However, there comes the issue of Security; a bug in a single routine say the interrupt handler could damage the PCB which in turn can make it difficult for OS to manage the affected process.
  • Changes made to the Process control block (like semantics or design changes) can affect various modules.

That's A Great Answer but figure should have been given there... But that's fine, i found it helpful thnx.. @Sayali

-->It can be said that the process control block defines the state of OS.

can u explain the above statement ? Actually i didn't understand it.

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