In modern multitasking systems, the Process Control Block (PCB) stores many different items of data, all needed for correct and efficient process management. PCB is the data structure that resides in the operating system kernel which contains the information needed to manage the process. The PCB is the representation of the process in the operating system. Though the details of these structures are system-dependent, there are some very common parts, which could be classified into three main categories:
Process identification data
Processor state data
Process control data
The role of the PCB is central in process management. It is accessed and/or modified by most operating system utilities, including those involved with scheduling, memory and I/O resource access, and performance monitoring. Data structuring for processes is often done in terms of PCBs. For example, pointers to other PCBs inside a PCB allow the creation of queues of processes in various scheduling states...