Assignment:
A hard disk drive has 10 disks and 18 surfaces available for recording. Each surface is composed of 200 concentric tracks and the disks rotate at 7200 r.p.m. Each track is divided into 8 blocks of 256 32-bit words. There is one read/write head per surface and it is possible to read the 18 tracks of a given cylinder simultaneously. The time to step from track to track is 1ms. Between data transfers the head is parked at the outermost track of the disk.
Calculate:
a. The total capacity of the disk drive.
b. The maximum data rate in bits/second.
c. The average access time in milliseconds. (Neglect the head load time and head settling time).
d. The average transfer rate when reading 256 word blocks located randomly on the disk.
e. The recording density (bits/inch) of the innermost and outermost tracks if the disk has a 6 inch diameter and the outermost track comes to 1 inch from the edge of the disk. The track density is 200 tracks/inch.