1. <networking> segmentation.
2. The process, or result, of splitting a large area of free memory (on disk or
in main memory) into smaller non-contiguous blocks. This happens after many
blocks have been allocated and freed. For example, if there is 3 kilobytes of
free space and two 1k blocks are allocated and then the first one (at the lowest
address) is freed, then there will be 2k of free space split between the two 1k
blocks. The maximum size block that could then be allocated would be 1k, even
though there was 2k free. The solution is to "compact" the free space by moving
the allocated blocks to one end (and thus the free space to the other).
As modern file systems are used and files are deleted and created, the total
free space becomes split into smaller non-contiguous blocks (composed of
"clusters" or "sectors" or some other unit of allocation). Eventually new files
being created, and old files being extended, cannot be stored each in a single
contiguous block but become scattered across the file system. This degrades
performance as multiple seek operations are required to access a single
Defragmenting consolidates each existing file and the free space into a
continuous group of sectors. Access speed will be improved due to reduced
The rate of fragmentation depends on the algorithm used to allocate space and
the number and position of free sectors. A nearly-full file system will fragment
MSDOS and Microsoft Windows use the simplest algorithm to allocate free clusters
and so fragmentation occurs quickly. A disk should be defragmented before
fragmentation reaches 10%.
See garbage collection.
FRAD « fragile « fragment « fragmentation »
FRAM » frame » frame buffer