All computer hard drives become fragmented
time. This is because when files are written to hard drives, the operating
system will try to write the file in a single
But when this fails - as it often does - the operating system
will split the file into multiple blocks
, with the end of each file
block pointing to the start of the next (ie a "fragmented block").
As time passes, this fragmentation of files will grow steadily worse
(the more files you have on your hard drive, the worse it will get). And
this in turn will gradually slow down your PC because the hard drive head
will have to work harder (ie visit more places on your hard drive)
to store and recover files.
For this reason it's a good idea to periodically defragment ("defrag") your
Defragmentation programs improve your system performance by rewriting
the files on your hard drive into larger, more contiguous blocks. This reduces
the amount of places that your hard drive head has to travel to, and this
in turn also helps extend disk life.
Windows PCs have come with an in-built disk defragmentation program
and have done ever since Windows began. This usually a version licensed from
Diskeeper Corporation. They were the first company to invent a defragger
that could be run without needing to shut a computer down way back in the
1980s. The Windows defragger can usually be found under Start -> Programs
-> Accessories -> System Tools -> Disk Defragmenter.
However, many people prefer to use a different disk defragmentation
program - either because other programs can do the job faster or they
provide more control over the defrag process that Windows' built-in
And here are 5 terrific freeware disk defragmenters that can give
Windows own software a run for its money.
PS: Mac OS X uses a different - and some would say smarter
- way to process files on a hard disk. Because of this Mac users rarely
(if ever) need to defrag their drives. For this reason all reviews on
this page are for Windows software.