The Process Control Block (PCB) is a data structure used by operating systems to store information about processes. It often stores a variety of process-related information, such as:
Process ID and parent process ID: These identifiers allow each process to be individually identified while also maintaining hierarchical relationships between parent and child processes.
Program code and data: The PCB may include references to the memory regions where the program code and data are stored. This information is critical for the operating system’s management of memory allocation and process access permissions.
CPU registers and program counter: When a process is interrupted or a context switch occurs, the PCB retains the contents of CPU registers. It also keeps track of the program counter, which indicates which instruction the CPU will execute next.