Disk file fragmentation refers to a condition where one or more files on a
disk do not occupy contiguous space (adjoining sectors and blocks).  Here is
how the condition can occur, what effect it has on you, and what you can do
about it.

Normally files are written to a contiguous area of the disk.  This results in
the fastest possible disk reading and writing accesses because the read/write
head of the disk drive can access the file with the least amount of head
movement.  When the disk approaches the point of being full, or has had a lot
of file creation and deletion activity, there will be no large areas of free
space remaining.  Large files that are to be saved on the disk will be divided
up and written to two or more free areas on the disk.  This is called file
fragmentation, and will increase the time required to access the file.  Program
files (.EXE and .COM extensions) will load more slowly (the program will still
run at the same speed once loaded), and fragmented data files used by database
packages can make some operations run much more slowly.

The number of files that are fragmented on a disk may be determined using the
DOS command CHKDSK to inspect each directory (see the help file CHKDSK for
details).  Fragmentation will occur most quickly on disks that have a lot of
file creation and deletion activity, or when files are enlarged and updated
often using word processors or database packages.  There is not much you can do
to avoid fragmentation, the problem lies in DOS's disk management techniques.
If a diskette gets fragmented, here's how to correct the problem.  First,
backup your working diskette to your normal backup the way you normally do.
Get a new diskette and initialize it in the same format as your fragmented
diskette (see the help file FORMAT for details).  Use the COPY *.* command to
copy the root directory and all subdirectories to your scratch diskette (see
the help file COPY for details).  Check this new copy of your diskette with
CHKDSK to verify that this copy is contiguous.  Format the original diskette
(you should have your normal backup and this new diskette as copies), then
copy the contents of the new diskette back to the reformatted original diskette
using the COPY or DISKCOPY command.  You should now have a contiguous copy of
your original fragmented diskette.  You can use the scratch diskette for other
purposes now.

For those of you with fixed disks and fragmentation problems, the solution is
quite ugly!  It's probably not worth worrying about until fragmentation is
causing you obvious decreases in performance, or even small files are getting
fragmented into many blocks.  This is a good time to do some house cleaning on
your fixed disk.  Check all your subdirectories for dormant files that could be
saved on floppy diskettes and erased from the disk (surely you can't have 10
megabytes of active information!).  After removing the dormant files run CHKDSK
again to see if the disk is still fragmented (it probably will be).  Be certain
that all your normal backups of the fixed disk are up to date.  Here comes the
ugly part!  Format a pile of diskettes and use the BACKUP command to backup the
entire fixed disk to this second set of diskettes (you should always have two
current copies of all file information; see the help files BACKUP and BACKUPS
for details).  The fixed disk must now be reformatted, and the backup copies
returned to the fixed disk using the RESTORE command (see the help file RESTORE
for details).

Fragmentation is not the end of the world.  Programs will certainly run
successfully with disks in this state.  It is up to you whether it is worth
spending the time and effort removing the fragmented files.
