Question

A FAT (file allocation table) based file system is being used and the total overhead of each entry in the FAT is 4 bytes in size. Given a 100 x 10⁶ bytes disk on which the file system is stored and data

block size is 10³ bytes, the maximum size of a file that can be stored on this disk in units of 10⁶ bytes is ______

Answer 1

Data:

Disk size = 100 × 10⁶ bytes

Data block size = 10³ bytes

Overhead per entry = 4 bytes

Formula: 

Total number of data disk block = \(\frac{{{\rm{Disk\;size}}}}{{{\rm{Data\;block\;size}}}}\)

Total space occupied by overhead = overhead per entry × number of entries

Maximum file size = total file system size – space consumed by overhead

Calculation:

Total number of data disk block = \(\frac{{{\rm{Disk\;size}}}}{{{\rm{Data\;block\;size}}}} = \frac{{100 \times {{10}^6}}}{{{{10}^3}}} = 100 \times {10^3}\)

Space occupied by overhead = 4 × 100 × 10³ = 0.4 × 10⁶

Maximum file size = 100 × 10⁶ bytes – 0.4 × 10⁶  

Maximum file size = 99.6 × 10⁶ bytes