# Explain the term FAT in the context of disk operating system. What will be the size of a disk and it’s FAT? – IGNOU MCA Assignment 2015 – 16

By | August 29, 2015

MASTER OF COMPUTER APPLICATIONS

Course Code : MCS-012
Course Title : Computer Organisation and Assembly Language Programming
Assignment Number : MCA(I)/012/Assignment/15-16
Maximum Marks : 100
Weightage : 25%

Explain the term FAT in the context of disk operating system. What will be the size of a disk and it’s FAT, if a disk has 64 tracks with each track having 16 sectors and size of each sector is 512 byte? You may take the cluster size as 4 sectors.

Given:

Disk has 64 tracks

Track has 16 sectors

Sector is 512 byte (0.5 KB)

Cluster size as 4 sectors

Find:

Disk Size (or Disk Capacity)?

It’s FAT (or FAT entries)?

Track Size (in KB) = No. of Sector x No. of Btyes

= 16 * 0.5 KB

= 8 KB

Cluster Size (in KB) = No. of Track x No. of Sector

= 64 * 8 KB

= 512 KB

Disk Size (in KB) = No. of Cluster x No. of Track

= 4 * 512 KB

= 2048 KB

=2MB

Disk Size (or Disk Capacity) = 2 MB

Note: FAT contains vital information; two copies of FAT are stored on the disk, so that in case one gets destroyed, the other can be used

It’s FAT (or FAT entries) = Disk Size (or Disk Capacity) / Cluster Size

= (2 * 1024 * 1024) / (2 * 1024)

= (2 * 1024 * 1024) / (2 * 1024)

= 1024 No. of entries

Note: FAT contains vital information; two copies of FAT are stored on the disk, so that in case one gets destroyed, the other can be used (Acutual entries = 1024 entries / 2 = 512 entries).