A disk head is at cylinder 50 and the pending requests are 82, 170, 43, 140, 24 and 16. Using SSTF, which request will be serviced first?

Options

  • A. 82
  • B. 43
  • C. 24
  • D. More than one of the above
  • E. None of the above

Correct Answer (Detailed Explanation is Below)

B. 43

Detailed Explanation

Explanation: SSTF selects the request closest to the current head position. From cylinder 50, the distances are 32 to 82, 7 to 43, 26 to 24, 90 to 140, 120 to 170 and 34 to 16. Therefore, cylinder 43 is serviced first.