What does a process control block (PCB) store?

A process control block (PCB) is a critical data structure in operating systems that maintains important information about a specific process. The PCB stores vital details such as the process state (e.g., running, waiting, or ready), the program counter that points to the next instruction to be executed, CPU registers, memory management information, and information regarding resources allocated to the process, such as file descriptors and I/O status.

This information is essential for the operating system to manage process scheduling effectively and to ensure smooth execution of applications. By keeping track of all this data, the PCB allows the operating system to switch between processes, handle interrupts, and manage resource allocation efficiently.

The other options involve components that are either broader in scope or unrelated to the specific management of processes, which is the main functionality of a PCB. For instance, physical hardware data, operating system configuration details, and networking information do not pertain directly to tracking the execution and resources of individual processes.