A Process Control Block (PCB for short) is a data structure that resides in the operating system kernel. A PCB stores the information that’s needed to manage a given process.
What information is stored in the Process Control Block?
Different systems implement the Process Control Block differently – and therefore store different information in the PCB – but there are some commonalities across different systems – we will list those. The Process Control Block stores important data related to a specific process, data like: the Process ID, the Process state, memory information, pointers to list of resources, and I/O information.
Process Control Blocks are changed during process creation, execution, suspension/resumption, and deletion. Most OS utilities modify and access PCB’s – this includes the utilites involved with memory scheduling, performance monitoring and I/O resource access.