Operating Systems | Input Output Systems | Question 5

Put the following disk scheduling policies results in minimum amount of head movement.
(A) FCFS
(B) Circular SCAN
(C) Elevator

Answer: (C)
Explanation: Circular scanning works just like the elevator to some extent. It begins its scan toward the nearest end and works its way all the way to the end of the system. Once it hits the bottom or top it jumps to the other end and moves in the same direction. Circular SCAN has more head movement than SCAN (elevator) because Circular SCAN has circular jump and it does count as a head movement.
SCAN (elevator) is the best choice here.

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