GATE | GATE-CS-2016 (Set 1) | Question 58
Consider a disk queue with requests for I/O to blocks on cylinders 47, 38, 121, 191, 87, 11, 92, 10. The C-LOOK scheduling algorithm is used. The head is initially at cylinder number 63, moving towards larger cylinder numbers on its servicing pass. The cylinders are numbered from 0 to 199. The total head movement (in number of cylinders) incurred while servicing these requests is:
Note : This question was asked as Numerical Answer Type.
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(A) 346
(B) 165
(C) 154
(D) 173
Answer: (A)
Explanation: The head movement would be:
63 => 87 24 movements 87 => 92 5 movements 92 => 121 29 movements 121 => 191 70 movements 191 --> 10 181 movement 10 => 11 1 movement 11 => 38 27 movements 38 => 47 9 movements
Total head movements = 346
So, option (A) is correct.
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