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 ________.

Given requests: $47, 38, 121, 191, 87, 11, 92, 10$. Sorted requests: $10, 11, 38, 47, 87, 92, 121, 191$.

Initial head position: $63$, moving towards larger cylinder numbers.

Under C-LOOK:

1. The head services requests greater than $63$ in ascending order up to the maximum requested cylinder:

   $$63 \to 87 \to 92 \to 121 \to 191$$

   Movement $= 191 - 63 = 128$

2. The head then jumps directly to the lowest requested cylinder without servicing any intermediate cylinders:

   $$191 \to 10$$

   Movement $= 191 - 10 = 181$

3. The head continues moving towards larger cylinder numbers to service the remaining requests:

   $$10 \to 11 \to 38 \to 47$$

   Movement $= 47 - 10 = 37$

Total head movement:

Thus, the total head movement is 346 cylinders.