Question

Modern high-capacity hard drives use a technique known as multiple zone recording, where the set of cylinders is partitioned into disjoint subsets known as recording zones. Each zone consists of a contiguous collection of cylinders. Each track in each cylinder in a zone has the same number of sectors, which is determined by the number of sectors that can be packed into the innermost track of the zone. Suppose both surfaces of platters are used for data recording. What is the capacity of a hard drive with the following parameters? (write your answer in gigabytes)

(a) number of platters = 8 (b) number of bytes per sector = 512 (c) number of zones = 2 (d) number of cylinders per zone 1= 8,000 (e) number of cylinders per zone 2= 10,000 (f) number of sectors per track for zone 1 = 800 (g) number of sectors per track for zone 2 = 400

Answer 1

Zone 1: 512 bytes/sector x 800 sectors / track x 2 sides / platter x 8 platters - all this in one cylinder
512 x 800 x 2 x 8 / 1024 = 6400 KB
To be multiplied by 8000 cylinders in zone 1
6400 x 8000 / 1024 / 1024 = 48.78 Gb in zone 1.

Zone 2: 512 bytes/sector x 400 sectors / track x 2 sides / platter x 8 platters (in 1 cylinder)
512 x 400 x 2 x 8 / 1024 = 3200 KBT
To be multiplied by 10000 cylinders in zone 2.
3200 x 10000 / 1024 / 1024 = 30.49 Gb

Total disk space including both zones is 79.27 Gb