Consider a disk queue with requests for I/O to blocks on cylinders 98, 183, 37, 122, 14, 124, 65, 67. Considering FCFS (First Come First Served) scheduling, the total number of head movements is, if the disk head is initially at 53?

Asked In Exam: BPSC TRE 3.0

Options

  • A. 640
  • B. 620
  • C. 630
  • D. More than one of the above
  • E. None of the above

Correct Answer (Detailed Explanation is Below)

A. 640

Detailed Explanation

FCFS services requests in the given order. Formula: Total head movement = sum of absolute differences between consecutive head positions. Here, |98-53|+|183-98|+|37-183|+|122-37|+|14-122|+|124-14|+|65-124|+|67-65| = 640.

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