GATE CSE 2024 | Set 1 | Question: 15

Question

Which of the following process state transitions is/are NOT possible?

• A. Running to Ready
• B. Waiting to Running
• C. Ready to Waiting
• D. Running to Terminated

Comments

When a process is in ready state then the resources which this process hold are not in use then at that time OS can prempt it's resources if necessary, then in that condition the state of this process changes to wait state.

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Yes  In case of resourse preemption by OS , process can transite from ready to waiting stage.

Answer 1

Consider the following process state diagram:

 

From the above process state diagram, it is clear that:

• A process can go from running to ready.
• A process can go from running to exit/terminate.
• A process can not go from waiting to running and ready to wait.

Option $(B,C)$ is correct.

Similar types of questions are asked in:

1.  GATE CSE 2020 | Question: 12
2.  GATE CSE 2009 | Question: 32

Comments

"If you prepare in the worst case, only then you will be able to perform in the best case" 😂

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You can check — sir has already noted that controversial statement separately, and they haven’t claimed it to be right. You’ve learned from him, so at least as a student, you should show respect to the faculty.

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@Ch.Anshika Mehria he changed it later. Be a bit more critical of others.

Answer 2

correct me if Iam wrong,

ready state contain those processes who require cpu for further execution.and waiting state contains those processes which are having I/o requirement.as per option 3,if a process can go to ready to waitiong state,it means that process needs i/o.but it is in the ready Q FOR using cpu.which is useless case.

Answer 3

It's a simple common-sense point — a process cannot move directly from the Ready state to the Waiting state. For a process to enter the Waiting state, it must first be in the Running state. If, while running on the CPU, it requests I/O or some other blocking operation, it will then transition from Running to Waiting. Once the I/O is complete, it moves from Waiting back to Ready. So, the transition from Waiting to Ready is possible, but not from Ready to Waiting directly.

Answer 4

OPTION B AND C ARE NOT ALLOWED