Answer-Using C-SCAN (Circular SCAN) disk scheduling on a 200-cylinder disk (0–199), with the head starting...

Moving right from 50, the head services 82, 140, 170, 190, then continues to the end of the disk at cylinder 199 a distance of 19950 149. It then jumps back to cylinder 0 counted here as 199 cylinders of movement, per the questions stated convention, and finally moves upward again to service 16, 24, 43, stopping at the last request, 43 a distance of 430 43. Total head movement 149 199 43 391 cylinders. C-SCANs key characteristic unlike plain SCAN is that it always services requests in only ONE direction, treating the disk as a circular list, which gives more uniform wait times across all cylinder positions.

Question

Using C-SCAN (Circular SCA

N disk scheduling on a 200-cylinder disk (0–199), with the head starting at cylinder 50 moving toward higher cylinder numbers, and pending requests at 82, 170, 43, 140, 24, 16, 190: Counting the return jump itself as head movement, what is the total head movement (in cylinders)?

A 332 cylinders

B 299 cylinders

C 208 cylinders

D 391 cylinders

E 383 cylinders

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