info from wikipedia on defragmentation link text

some defrag programs also add optimisation of the most frequently used files so the most frequent files are moved to the fastest access part of the hdd. i have tested many and use a free program called jk defrag download from link text

good info of defrag tips scroll down the jkdefrag page very interesting and easy read

Data retrieval from a fragmented disk is much complicated fetch it from a de-fragmented disk. De-fragmentation rearranges the memory allocation of your file system, and thus increase the performance of your system.

Why defrag if you have lots of disk space?

Fragmentation is basically broken-up pieces (or fragments) of files and free space randomly scattered across a disk.

When the disk is fragmented, it has to work much harder to find the file pieces when accessing the file and then again to save the file into pieces when it is revised. This happens each time the file is accessed, edited and then saved (again in pieces as the free available space is also in pieces from files being deleted).

Fragmentation has little to do with total available disk space. Say for example that a 100 MB file is edited and increased to 150MB. The disk will not be able to write the additional 50MB next to the original 100 MB if there is already a file next to it.

If the next file in line was a deleted 25 MB file, half of the newly created 50 MB may go there and the other half will go wherever the next available space is.

Now this happens repeatedly with EACH file written, deleted, edited saved, etc. This all amounts to the disk wearing out faster as it is being used A LOT more than it would be if the files were whole instead of broken into pieces (especially when you consider that some files are broken into thousands of pieces -- I have seen a single file reportedly broken into more than 14,000 fragments....)

Basic defragmentation is the process of locating these file pieces (or fragments) and putting them back together so they are contiguous or "whole" again.

Good defragmentation would do this automatically with little to no resource hit so that the computer can be used while it is defragmenting.

Better defragmentation would do all the above and also consolidate the free space fragments so there is enough space in which to write or revise future files.

The best, ultimate defrag program would do all of the above and also prevent most files from being fragmented in the first place.

Defragmentation saves time and also reduces disk wear -- it makes the disk last a lot longer if it is defragmented frequently and thoroughly.

There is A LOT more information on fragmentation and how to resolve it at the Defragmentation Information Center here: http://www.diskeeper.com/defrag/defragmentation-center/.

Hope this helps!

BillR TechSpec ..