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(computer science)
The tendency of files in disk storage to be divided up into many small areas scattered around the disk.
(cell and molecular biology)
Amitotic division; a type of asexual reproduction.
(mining engineering)
The blasting of coal, ore, or rock into pieces small enough to load, handle, and transport without the need for hand-breaking or secondary blasting.
Disordered behavior and mental processes.




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 fragmented file.

Defragmenting consolidates each existing file and the free space into a continuous group of sectors. Access speed will be improved due to reduced seeking.

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 more quickly.

MS-DOS 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.


(1) See Android fragmentation.

(2) Storing data in non-contiguous areas on disk. As files are updated, new data are stored in available free space, which may not be contiguous. Fragmented files cause extra head movement, slowing disk accesses. A defragger program is used to rewrite and reorder all the files.

(3) In an IP network, breaking a data packet into smaller pieces in order to accommodate the maximum transmission unit of the network. See IP fragmentation.
References in periodicals archive ?
Condusiv Technologies, the leader in I/O reduction software for virtual and physical server environments, today announced the release of Diskeeper 15 Server, highlighting an industry-first fragmentation prevention solution for SAN storage systems connected to physical servers to keep both servers and storage running like new.
In order to perform state forest enterprise area ranking (based on forest fragmentation component importance criterion) and assess the compatibility of framework, custom SAW and TOPSIS methods based extension MCSDSS for ArcGIS software has been developed during this study.
3, it is concluded that the fluidized-bed temperature is an important factor of oil shale primary fragmentation, and that higher fluidized-bed temperature results in severer fragmentation.
In the following test descriptions and analysis, the comparisons are all before and after defragmentation at each specific fragmentation level tier.
Although fragmentation has some undesirable consequences, it is an inevitable part of the competitive process.
District Court to be no more than a freak occurrence, try this experiment: Install NT and MS Office on a new machine, then run an analysis of fragmentation (Diskeeper Lite, which includes a fragmentation analysis utility, can be downloaded free from www.
It also seems that there are time-sequences when global economic processes require the establishment of larger territorial states (for example the constitution of the Ottoman or of the Habsburg states, or the unification of Germany and Italy in the 19th century), followed by periods of political fragmentation (the emergence of nation-states all over Eastern Europe between 1830 and 1918-23), followed by political and economic standardization of larger clusters of countries (the Cold-War division of Europe into two antagonistic power-blocs), replaced again with political fragmentation (Eastern Europe and the Soviet space after the collapse of Communism).
A good indication of the fragmentation of the social sciences is the increasing number of specialized journals.
The other problems of the old system of providing health care - access and fragmentation - are also improved.
Perhaps the issue most threatening to the profession's continued growth is fragmentation in the areas of title transition, professional preparation, credentialing, and professional associations, which could prove harmful to the professional identity and the attainment of greater status for rehabilitation counseling as a profession.
We are finally getting a deep look into the hard facts on the impact of the rise of I/O requests caused by file fragmentation," said Jerry Baldwin, CEO of Condusiv Technologies.
Belmonte knew of some fragmentation experiments performed in the early 1990s.