IBM Extended Density Format

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The IBM eXtended Density Format (XDF) is a way of formatting standard high-density 3.5" and 5.25" Floppy disks to larger-than-standard capacities. It is supported natively by IBM's PC-DOS versions 7 and 2000 and by OS/2 Warp 3 onward, using the XDF and XDFCOPY commands (directly in OS/2).

When formatted as XDF disks, 3.5" floppies can hold 1860 KiB, and 5.25" floppies can hold 1540 KiB, using different number of sectors as well as different sector size per sector (not all sectors in the same track are of the same size). However, the first cylinder uses standard formatting, providing a small FAT12 section that can be accessed without XDF support and on which can be put a ReadMe file or the XDF drivers.

Floppy distributions of OS/2 3.0, PC-DOS 7 and onward used XDF formatting for most of the media set.

[edit] See also

• 2M, a program that allows the formatting of high capacity floppy disks
• fdformat, a program that allows the formatting of high capacity floppy disks
• MAXI Disk, a program that allows the formatting of high capacity floppy disks
• DMF, a high-density diskette format used by Microsoft