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

Hint:

A process must pass through the Ready state to transition from Waiting to Running. Similarly, a process cannot directly transition from Ready to Waiting.

Answer 1

The Correct Option is B

Step 1: Understand process state transitions. Process states include: Ready: The process is ready to run but is waiting for CPU time. Running: The process is currently executing on the CPU. Waiting: The process is waiting for an event (e.g., I/O completion). Terminated: The process has finished execution. Step 2: Analyze each transition.
1. Running to Ready: This is possible when the process is preempted by the scheduler due to a higher-priority process or time slice expiration.
2. Waiting to Running: This is NOT possible. A process must first transition from the Waiting state to the Ready state when the event it is waiting for completes. It can then move from Ready to Running.
3. Ready to Waiting: This is NOT possible. A process in the Ready state can only transition to the Running state when scheduled. Waiting occurs after execution begins (e.g., when it requests I/O).
4. Running to Terminated: This is possible when the process completes its execution. Step 3: Conclude the impossible transitions.
From the above analysis, the transitions Waiting to Running and Ready to Waiting are NOT possible. Final Answer: \[ \boxed{\text{(2) Waiting to Running, (3) Ready to Waiting}} \]