IBM Extended Density Format
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The IBM eXtended Density Format (XDF) is a way of
superformatting Superformatting is the process of formatting a floppy disk at a capacity that the disk is not designed for. It can ruin a floppy disk, but it is used in some floppy-based Linux distros to increase the room for applications and utilities. muLinux ...
standard high-density 3½-inch and 5¼-inch floppy disks to larger-than-standard capacities. It is supported natively by IBM's
PC DOS PC or pc may refer to: Arts and entertainment * Player character or playable character, a fictional character controlled by a human player, usually in role-playing games or computer games * '' Port Charles'', an American daytime TV soap opera * ...
versions 7 and 2000 and by
OS/2 OS/2 (Operating System/2) is a series of computer operating systems, initially created by Microsoft and IBM under the leadership of IBM software designer Ed Iacobucci. As a result of a feud between the two companies over how to position OS/2 r ...
Warp 3 onward, using the XDF and XDFCOPY commands (directly in OS/2). When formatted as XDF disks, 3½-inch floppies can hold 1860 kB, and 5¼-inch floppies can hold 1540 kB, using different number of sectors as well as different sector size per track (not all sectors in the same track are of the same size). However, the first cylinder uses standard formatting, providing a small
FAT12 File Allocation Table (FAT) is a file system developed for personal computers. Originally developed in 1977 for use on floppy disks, it was adapted for use on hard disks and other devices. It is often supported for compatibility reasons by ...
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. Floppy disks formatted using XDF can only be read in floppy disk drives that are attached directly to the system by way of a FDC. Thus,
USB Universal Serial Bus (USB) is an industry standard that establishes specifications for cables, connectors and protocols for connection, communication and power supply (interfacing) between computers, peripherals and other computers. A broad ...
attached floppy drives cannot read XDF formatted media.


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 * DMF, a high-density diskette format used by Microsoft * FD32MB, technically unrelated special HD floppy format supported by
LS-240 The SuperDisk LS-120 is a high-speed, high-capacity alternative to the 90 mm (3.5 in), 1.44  MB floppy disk. The SuperDisk hardware was created by 3M's storage products group Imation in 1997, with manufacturing chiefly by ...
SuperDisc drives also providing a traditionally formatted mini file system containing only a
README In software development, a README file contains information about the other files in a directory or archive of computer software. A form of documentation, it is usually a simple plain text file called README, Read Me, READ.ME, README.TXT, R ...
file IBM storage devices Floppy disk computer storage {{Compu-storage-stub