Consider the following disk request sequence for a disk with 100 tracks. 60,…
2023
Consider the following disk request sequence for a disk with 100 tracks. 60, 45, 21, 67 Head pointer starting at 60 and moving in the left direction. Find the number of head movements in cylinders using FCFS scheduling.
- A.
85
- B.
90
- C.
80
- D.
193
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Correct answer: A
In FCFS, we move from the current position to the next track in the sequence, regardless of the direction or distance.
Start at 60: The first request is 60. Since the head is already at 60, movement = 0.
Move to 45: |60 - 45| = 15 cylinders.
Move to 21: |45 - 21| = 24 cylinders.
Move to 67: |21 - 67| = 46 cylinders.
Total Head Movement:
15 + 24 + 46 = 85 cylinders