Can someone check this and let me know if I messed up at the end... it doesn\'t
ID: 3853145 • Letter: C
Question
Can someone check this and let me know if I messed up at the end... it doesn't look correct to me.
Given the following:
Number of cylinders on the disk =6000
Number of platters=3
Number of surfaces per platter=2
Number of sectors per track=400
Number of bytes per sector=512
Disk allocation policy=contiguous cylinders
How many cylinders should be allocated to store a file of size 1 Gbyte?
Number of tracks in a cylinder = number of platter * number of surfaces per platter?
6 = 3 *2
Size of track = number of sectors in track * size of sector
204,800 bytes = 400 * 512
Capacity in 1 cylinder = number of tracks in cylinder * size of track
1,228,800= 6 * 204,800
Number of cylinders needed to store a file of 1 Gbyte?
1 Gigabyte = 1,073,741,824 Bytes
Number of cylinders needed for 1 gbyte = size of 1 gbyte / capacity of 1 cylinder
874 cylinders = 1,073,741,824 Bytes / 1,228,800
(b)How much is the internal fragmentation caused by this allocation?
Internal fragmentation = 874 cylinders – 1 gbyte
=
Explanation / Answer
Smallest unti to be utilized in a disk is a sector, and since contiguous cylinders policy is being used, sectors of all 6 surfaces the written concurrently, and hence must be utilized at the same time
So size per sector (for all 6 surfaces) = 3 * 2 * 512 = 3072
Size of file = 10243
Therefore 349525.33 are required and 349526 sectors are allocated
size of allocation = 6 * 349526 = 1073743872bytes
and required = 1073741824bytes
so fragmented: 2048byes