The operating system maintains information about each process in a data structure called a process control block (PCB). The PCB is created when a new process is started by a user and contains information like the process state, program counter, CPU registers, scheduling information, memory management details, accounting information, and I/O status. PCBs allow the OS to efficiently manage and switch between processes by providing all necessary process details in one place.

2. INTRODUCTION
•OS MAINTAINS INFORMATION OF EACH PROCESS IN A RECORD OR
DATA STRUCTURE CALLED PCB
•EACH USER PROCESS HAS A PCB.
•IT IS CREATED WHEN A USER CREATES A PROCESS & IT IS
REMOVED FROM THE SYSTEM WHEN THE PROCESS IS KILLED.
•ALL THESE PCBS ARE KEPT IN MEM RESERVED FOR THE OS.

3. PROCESS STATE DIAGRAM
Reference:= Abraham Silberchatz, Operating System Concept, Chapter 3, Topic 3.1.3

4. PROCESS CONTROL BLOCK (PCB)
Information
associated
with each
process
Process
state
Program
counter
CPU
registers
CPU
scheduling
information Memory-
management
information
Accounting
information
I/O status
informatio
n
Reference:= Abraham Silberchatz, Operating System Concept, Chapter 3, Topic 3.1.3

5. Reference:= Abraham Silberchatz, Operating System Concept, Chapter 3, Topic 3.1.3

6. CPU SWITCH FROM PROCESS TO PROCESS
Reference:= Abraham Silberchatz, Operating System Concept, Chapter 3, Topic 3.1.3