How is the Address Space (of a process) and Process Control Block (PCB) are related in Operating System?

Question

If we talk about Address Space of a process it is the virtual address range which includes static data, stack and heap memory for that particular process. And coming to Process Control Block (PCB) which is a data structure maintained by operating system for each process it manages, where PCB includes a lot of information about the process like process no., process state, program counter, list of open files, cpu scheduling info ...and more.

Now this is the point where I got confused that Address Space is also a memory which stores information about a process and similar thing is done by PCB too. Then how these are connected to each other. I am not able to visualize this in my mind. Why we have these two things existing simultaneously. Isn't it possible to achieve our goal just by using PCB?

Answer 1

Process Address space refer to memory regions the process is using. It typically consists of heap, stack, initialized data, uninitialized data and text. There are mainly two address spaces of a process -- logical and physical. The PCB is a structure resides in kernel to track the state of process. One of the things PCB contain is memory information. In a typically system, PCB may contain information about pages the process has. To answer your question, Process Address space is an idea built on top of PCB and many other things (such as page table).