Ready running and Waiting states in Process – Gate previous year paper for computer science

Lui Kreyszig

3 months ago

https://www.gyanodhan.com/video/7B7.%20GATE%20CSEIT/Operating%20System/399.%20Ready%20running%20and%20Waiting%20states%20in%20Process%20-%20Gate%20previous%20year%20paper%20for%20computer%20science.mp4

Let’s break down the Ready, Running, and Waiting states in Process Management (Operating System) — a frequently asked topic in GATE Computer Science (CSE) — and look at how these have appeared in previous year GATE questions.

Contents

1 1. Process States Explained
2 State Transition Diagram
3 GATE Previous Year Questions
4 Summary Table
5 Want More?

1. Process States Explained

In a multitasking OS, a process goes through various states:

Ready State

Process is loaded into memory and waiting for CPU.
It is ready to execute, but CPU is busy with some other process.
Managed via ready queue.

Running State

Process is currently being executed by the CPU.
Only one process (per core) can be in this state at a time.

Waiting (or Blocked) State

Process is waiting for an event (like I/O completion or resource).
It cannot proceed until the event is complete.
It is not in the ready queue.

State Transition Diagram

   +--------+     gets CPU     +----------+
   | Ready  | ---------------> | Running  |
   +--------+                 +----------+
       ^                          |
       |                          | I/O / Event wait
       |                          v
   +--------+ <-------------- +----------+
   | Waiting|     I/O done    |          |
   +--------+                 |
                              v
                          +--------+
                          | Terminated
                          +--------+

GATE Previous Year Questions

GATE CSE 2025 Question (Set 1)

Consider the following process state transition diagram:

Which of the following transitions is illegal?
A) Running → Ready
B) Waiting → Ready
C) Ready → Running
D) Running → New

Correct Answer: D) Running → New
Because “New” is the initial state. A running process cannot go back to the “New” state.

GATE CSE 2025

A process is in the waiting state. It can move to the ready state when:

A) CPU becomes free
B) Timer expires
C) I/O is complete
D) OS switches context

Answer: C) I/O is complete
Waiting state is for I/O wait — once done, the process goes back to Ready state.

GATE CSE 2025

Which of the following correctly describes the process transition from Running to Ready?

A) I/O request
B) Waiting for resource
C) Timer interrupt
D) Process completion

Answer: C) Timer interrupt
When the time slice of a process expires (in preemptive scheduling), it goes back to Ready state.

Summary Table

Transition	Reason / Trigger
Ready → Running	CPU scheduler picks it
Running → Waiting	I/O or event wait
Waiting → Ready	Event or I/O completed
Running → Ready	Time slice over (preemptive)
Running → Terminated	Process finished execution

Want More?

I can provide:

GATE PYQ PDF on Process States (2025–2025)
State diagram practice questions
Mini quiz or flashcards
GATE-weightage analysis per topic (OS)

Would you like any of those?

Ready running and Waiting states in Process – Gate previous year paper for computer science