If the overhead for formatting a disk is $$96$$ bytes for $$40000$$ bytes sector, Compute the unformatted capacity of the disk of the following parameters:
Number of surface: $$8$$
Outer diameter of the disk : $$12cm$$
Inner diameter of the disk: $$4cm$$
Inter track space: $$0.1mm$$
Number of sectors per track: $$20$$

A certain moving arm disk-storage device has the following specifications:
Number of tracks per surface $$=4004$$
Track storage capacity $$=130030$$ bytes
Disk speed $$=3600$$ rpm
Average seek time $$=30$$ m secs.
Estimate the average latency the disk storage capacity and the data transfer rate.

Assuming the current disk cylinder to be $$50$$ and the sequence for the cylinders to be
$$1, 36, 49, 65, 53, 1, 2, 3, 20, 55, 16, 65$$ and $$78$$ find the sequences of servicing using
(i) shortest-seek time first $$(SSTF)$$
(ii) elevator disk scheduling polices.