Process control block

Question 1

What is a zombie process?

Answer 1

This is a process that has completed execution but still has no entry in the process table. It is created when a parent process does not retrieve its child process exit status through a wait system call.

Question 2

With the help of a diagram explain the process control block.

Answer 2

This is the way a process is represented in the operating system. It is also called the task control block. The information included in a PCB include
Acronym: MIA 2C 2P

-> Memory management:
This information includes the value of base and limit registers and the page or segment tables

-> Input and Output Status Information:
Includes list of open files and Input and output devices allocated to the process

-> Accounting Information:
Includes: account numbers, job process numbers, and amount of CPU being used

-> CPU Scheduling Information:
Includes, process priority, and pointers to scheduling queues.

-> CPU registers:
Includes information about the number and type of registers in the computer architecture

-> Process State:
Includes information about which state the process is currently in

-> Program counter:
Indicates the address for the next instruction to be executed for the process

(DRAW DIAGRAM HERE)

Question 3

What is on the PCB diagram in order?

Answer 3

Acrcronym: 4P RML
-> Pointer, Process State
-> Process number
-> Program counter
-> Registers
-> Memory Limit
-> List of open files