A disk head is initially at cylinder 50. The request queue is 82, 170, 43, 140, 24 and 16. Using FCFS disk scheduling, what is the total head movement?

Options

  • A. 208 cylinders
  • B. 226 cylinders
  • C. 238 cylinders
  • D. More than one of the above
  • E. None of the above

Correct Answer (Detailed Explanation is Below)

E. None of the above

Detailed Explanation

Explanation: In FCFS, requests are serviced in the order in which they arrive. The total head movement is |50−82| + |82−170| + |170−43| + |43−140| + |140−24| + |24−16| = 32 + 88 + 127 + 97 + 116 + 8 = 468 cylinders. Since 468 cylinders is not given in options A, B or C, the correct answer is None of the above.

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