The Process Control Block

Process Control Block (PCB)

What is a Process Control Block?

A Process Control Block (PCB) is a data structure that stores information about a process in an operating system.

Components of a PCB

• Process ID (PID): A unique identifier for the process.
• Program Counter (PC): The current instruction being executed.
• Registers: The current values of the CPU registers.
• Memory Limits: The amount of memory allocated to the process.
• Priority: The priority of the process.
• Status: The current state of the process (e.g., running, waiting, zombie).
• Open Files: A list of files currently open by the process.
• Resource Usage: Information about the resources used by the process.

Functions of a PCB

• Process Identification: The PCB provides a unique identifier for each process.
• Process Scheduling: The PCB provides information needed for process scheduling.
• Resource Management: The PCB tracks the resources used by each process.
• Process Termination: The PCB is used to clean up resources when a process terminates.

Importance of PCBs

• Enable Multitasking: PCBs allow the operating system to manage multiple processes.
• Improve System Performance: PCBs help the operating system optimize resource allocation.
• Enhance Security: PCBs help the operating system enforce access controls and resource limits.