Each process in an operating system is represented by a process control block (PCB). The PCB is a data structure that contains information needed to manage a particular process, including the process state, program counter, CPU registers, memory management details, and I/O status. It serves as a repository for any information that may vary from process to process, such as scheduling priorities, memory values, and accounting information like CPU time used.

1. PROCESS
CONTROL BLOCK

3. WHAT IS PROCESS CONTROL BLOCK ?

4. PROCESS CONTROL BLOCK
 Each & every process in the operating
system is represented by PROCESS
CONTROL BLOCK
 Process Control Block ~ Task Control
Block or Task Struct

5. WHAT EXACTLY IS PCB ?
 Its is a data structure in the operating
system kernel containing the information
needed to manage a particular process.
 The PCB is “ the manifestation(visible) of
a process in an operating system”

6. PROCESSCONTROLBLOCK (PCB)

7. PROCESS CONTROL BLOCK (PCB)
PCB consist of following information~
 Pointer.
 Process state.
 Process number.
 Program counter.
 CPU register.
 CPU scheduling information.
 Memory management information.
 Accounting information.
 I/O status information.

8.  POINTER ~ Its contains the address of another
process which is present in the ready queue
 PROCESS STATE ~ Its contains the information
about the state of the process i.e.,
 NEW
 READY
 RUNNING
 WAITING
 HALTED

9.  program COUNTER ~ The counter specifies
the address of the next instruction to be
executed.
 CPU REGISTERS ~ The register vary in number
and type depending in the type of computer
architecture, they include:
 Accumulators, index register, stack pointer and
general purpose registers

10.  CPU SHEDULING INFORMATION~ This
information includes
 Process priority
 Pointer to scheduling queues
 Other scheduling parameters.
 MEMORY MANAGEMENT INFORMATION~ This
information includes
 Value of base and limit of registers
 Page tables
 Segment tables
 Depending on the memory system used by the
operating system.

11.  ACCOUNTING INFORMATION ~ This information
includes
 amount of CPU and real time used
 time limit
 account number
 job or process number etc.
 I/O STATUS INFORMATION ~ This information
includes
 list of I/O devices allocated to the process
 list of open files etc.
Hence, the PCB serves as the
repository for any information that may be vary from process to
process.