- Definition of PCB
- [[#Definition of PCB#Key fields|Key fields]]
- [[#Definition of PCB#Functions of PCB :|Functions of PCB :]]
Definition of PCB
A Process Control Block (PCB) is a data structure that contains information about a process. It serves as a central repository of details that the operating system needs to manage and track the execution of a process.
Key fields
- Process ID (PID): A unique identifier for the process.
- Process State: The current state of the process (e.g., running, waiting, ready).
- Program Counter (PC): The address of the next instruction to be executed.
- Registers: The values stored in the process’s registers.
- Memory Management Information: Details about the memory allocated to the process, including base address, limit, and page table.
- Open Files: A list of files that the process has open.
- Parent Process ID: The PID of the process’s parent process.
- Child Process IDs: A list of PIDs of the process’s child processes.
- Priority: The priority level assigned to the process.
- Scheduling Information: Data related to the process’s scheduling, such as arrival time and waiting time.
Functions of PCB :
- Process Creation and Termination: When a process is created, a PCB is allocated for it. When a process terminates, its PCB is deallocated.
- Process Scheduling: The operating system uses the PCB to determine which process should be executed next based on its priority and other scheduling criteria.
- Context Switching: When a process is preempted or voluntarily yields the CPU, its PCB is saved, and the PCB of the next process to be executed is loaded.
- Inter-Process Communication: The PCB contains information about the open files and other resources that processes can use to communicate with each other.
- Memory Management: The PCB stores details about the memory allocated to the process, which is used by the operating system to manage memory allocation and deallocation.
the PCB is a crucial data structure that plays a central role in the management and execution of processes in an operating system.