[Solved] Which of the following statements about the C-SCAN disk scheduling algorithm is INCORRECT? - Ans: C-SCAN eliminates starvation by always servicing the closest request next. | Operating Systems

Operating Systems - Disk Scheduling - SSTF, SCAN, C-SCAN

Which of the following statements about the C-SCAN disk scheduling algorithm is INCORRECT?

AC-SCAN services requests in one direction only and jumps back to the beginning without servicing requests on the return trip.

BC-SCAN eliminates starvation by always servicing the closest request next.

CC-SCAN can cause longer average seek times than SSTF because it ignores the closest requests on the return path.

DC-SCAN provides a more uniform wait time compared to SCAN by treating the disk as a circular list.

Step-by-Step Solution

Step 1: Review C-SCAN behavior
C-SCAN moves the head in one direction, servicing requests, then jumps back to the start without servicing requests on the return.
Step 2: Understand fairness and wait times
This approach provides uniform wait times and avoids starvation.
Step 3: Analyze each option
C-SCAN eliminates starvation by always servicing the closest request next. is incorrect because C-SCAN does not always service the closest request next; it ignores requests on the return jump.
Final Answer:
Option B -> Option B
Quick Check:
C-SCAN eliminates starvation by always servicing the closest request next. is the only incorrect statement about C-SCAN.

Quick Trick: C-SCAN jumps back without servicing requests, so closest next request isn't guaranteed

Common Mistakes:

MISTAKES

Trap Explanation:

PITFALL

Option B is tempting because candidates often think 'closest request next' applies to all algorithms; Options A, C, and D correctly describe C-SCAN's behavior and trade-offs.

Interviewer Note:

CONTEXT

Tests candidate's ability to spot subtle misconceptions about C-SCAN's servicing order and starvation properties.

Master "Disk Scheduling - SSTF, SCAN, C-SCAN" in Operating Systems

2 interactive learning modes - each teaches the same concept differently

More Operating Systems Quizzes

Which of the following statements about the C-SCAN disk scheduling algorithm is INCORRECT?