File system
In computing, file system fragmentation, sometimes called file system aging, is the tendency of a file system to lay out the contents of files non-continuously to allow in-place modification of their contents. It is a special case of data fragmentation. File system fragmentation increases disk head movement or seek time (where it applies), which are known to hinder throughput. The correction to existing fragmentation is to reorganize files and free space back into contiguous areas, a process called defragmentation.