Aims of defragmentation

Aims of defragmentation

Reading and writing data on a heavily fragmented file system is slowed down as the time needed for the disk heads to move between fragments and waiting for the disk platter to rotate into position is increased (see seek time and rotational delay). For many common operations, the performance bottleneck of the entire computer is the hard disk; thus the desire to process more efficiently encourages defragmentation. Operating system vendors often recommend periodic defragmentation to keep disk access speed from degrading over time.

Fragmented data also spreads over more of the disk than it needs to. Thus, one may defragment to gather data together in one area, before splitting a single partition into two or more partitions (for example, with GNU Parted, or PartitionMagic).

Defragmenting may help to increase the life-span of the hard drive itself, by minimizing head movement and simplifying data access operations.