Defragment disks serve to break up and rejoin the existing data on a disk sector. Among the formats supported for the defrag FAT (16/32), NTFS, RAW, and System Data Store. Defragment process is very useful for acceleration of work the computer, it is viewed from the disk before and after Defrag.
The logic is: When the disk (Rewritable) in the contents of the data in a sector A, then fill in the data B and then the subsequent data C, then when the data B in the clear, to perform random access from sector to sector A sector B C must pass through which is an Empty Sector there will be a delay of access “.