Consider the following statements about process state transitions for a system…
2020
Consider the following statements about process state transitions for a system using preemptive scheduling.
I. A running process can move to ready state.
II. A ready process can move to running state.
III. A blocked process can move to running state.
IV. A blocked process can move to ready state.
Which of the above statements are TRUE ?
- A.
I, II, and III only
- B.
II and III only
- C.
I, II, and IV only
- D.
I, II, III and IV only
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Correct answer: C
Answer: The true transitions are: I (a running process can move to ready), II (a ready process can move to running), and IV (a blocked process can move to ready).
Running → Ready: True. In preemptive systems a running process may be preempted (for example by a timer interrupt or a higher-priority arrival) and placed back into the ready queue.
Ready → Running: True. The scheduler selects a ready process to run, so a ready process can move to running.
Blocked → Ready: True. When the event a process is waiting for occurs (e.g., I/O completion), the blocked process becomes ready.
Blocked → Running: False. A blocked process cannot go directly to running; it must first transition to ready and then be scheduled to run.