FDFormat is one of those programs like PKZip, where once you use it you wonder how you ever got along without it. The simple explanation of what it does is that it formats standard 1.44mb floppy disks to 1.68mb DMF format (the kind MS used to ship on), or to 1.72mb.

The complex explanation is that it optimizes, not increases utilized space on the disk my modifying the number of tracks, the number of sectors per track and the number of sectors per cluster. It can also modify the interleave of the disk, and it can do something called sector sliding. FDF can also change the number of root directory entries, which define the maximum number of files and directories that can go in the root of the disk, and it can change the interleave, which is the number of revolutions the drive takes to read one track.

For more information, download the package at:

ftp://src.doc.ic.ac.uk/packages/linux/tsx-11-mirror/680x0/bin/system/floppy/fdformat.tar.gz
(for Linux) or

ftp://ftp1.sunet.se/puba/pc/mirror/simtelnet/msdos/diskutil/fdform18.zip
(for Windows/DOS)