If the five-state process model is extended to support asynchronous I/O notifications, which modification to the state transitions would best handle this feature without compromising process synchronization?
hard🎤 Interviewer Follow-up Q10 of Q15
Operating Systems - Process State Machine - Five-State Model
If the five-state process model is extended to support asynchronous I/O notifications, which modification to the state transitions would best handle this feature without compromising process synchronization?
AAdd an intermediate 'Ready-Waiting' state to represent processes notified but not yet scheduled.
BKeep the existing Waiting state but add event flags in the PCB to track asynchronous completions before moving to Ready.
CAllow processes to transition directly from Waiting to Running upon asynchronous notification.
DEliminate the Waiting state and rely solely on the Ready state with asynchronous event polling.
Step-by-Step Solution
Solution:
Step 1: Understand asynchronous I/O impact
Processes receive notifications asynchronously but must still synchronize before running.
Step 2: Modify PCB with event flags
Tracking asynchronous completions via flags allows correct Waiting to Ready transition.
Step 3: Adding new states complicates the model unnecessarily.
Step 4: Direct Waiting to Running transition risks race conditions.
Step 5: Eliminating Waiting state loses synchronization semantics.
Final Answer:
Option B -> Option B
Quick Check:
PCB flags enable asynchronous tracking without new states [OK]
Quick Trick:Use PCB flags to track async I/O, keep Waiting state [OK]
Common Mistakes:
MISTAKES
Adding unnecessary intermediate states
Skipping Ready state before Running
Removing Waiting state entirely
Trap Explanation:
PITFALL
Candidates may overcomplicate or oversimplify asynchronous I/O handling in states.
Interviewer Note:
CONTEXT
Assesses ability to extend classic models for modern asynchronous features.
Master "Process State Machine - Five-State Model" in Operating Systems
2 interactive learning modes - each teaches the same concept differently
