Explanation
Each disk scheduling algorithm works according to the following mechanisms:
A. SSTF (Shortest Seek Time First) → 1: Selects the request with the minimum seek time from the current head position, servicing nearby tracks first.
B. SCAN → 2: Also known as the Elevator Algorithm, the disk head moves from one end of the disk to the other end, servicing requests along the way, and then reverses direction.
C. C-SCAN (Circular SCAN) → 3: Moves the head in one direction to service requests, but upon reaching the end, it returns immediately to the beginning boundary without servicing requests on the return trip to provide a uniform wait time.
D. LOOK → 4: Similar to SCAN, but instead of going all the way to the disk boundaries, it reverses direction immediately after servicing the last request in that direction.
Therefore, the correct mapping is A-1, B-2, C-3, D-4.
