format -- format floppy disks


format [ -n ] [ -v ] [ -f ] [ -q ] [ device ] [ -i interleave ]


The format command formats diskettes for use on a UNIX system. It may be used either interactively or from the command line. The default drive is specified in /etc/default/format.


The following command line options are available:

Suppresses the interactive feature. The format program does not wait for user-confirmation before starting to format the diskette. Regardless of whether you run format interactively, track and head information is displayed.

This specifies the device to be formatted. The default device is specified in /etc/default/format.

-i interleave
Specifies the interleave factor.

Quiet option. Suppresses the track and head output information normally displayed. Although this option does not suppress the interactive prompt, it would typically be used with -f to produce no output at all.

Specifies format verification.

Specifies that the diskette is not to be verified (overrides verify entry in /etc/default/format).
The file /etc/default/format is used to specify the default device to be formatted and whether or not each diskette is to be verified. The entries must be in the format DEVICE=device and VERIFY=[yYnN], as in the following example:
The device must be a character (raw) device.


To run format interactively, enter:


followed by any of the legal options except -f, and press <Return>. When you run format interactively, you see the prompt:

   insert diskette in drive and press return when ready
When you press <Return> at this prompt, format begins to format the diskette.

If you specify the -f option, you do not see this prompt. Instead, the program begins formatting immediately upon invocation.

Unless you specify the -q option, format displays which track and head it is currently on:

   track #   head #
The number signs above are replaced by the actual track and head information.

Formatting in floptical drives

720KB (DD), 1.44MB (HD), and 21MB (VHD), 3.5" floppy disks may be formatted in an installed floptical drive. The special device naming scheme is documented on Sflp(HW).


To format a diskette in the default drive, with verification:

format -v

To format a diskette in the second drive (a 3.5" high density disk not listed in /etc/default/format):

format -v /dev/rfd1135ds18

Note that you cannot use the abbreviated device names (/dev/rfd0 and /dev/rfd1) when formatting floppy disks. You must use the full device names that specify disk density. For example, use /dev/rfd0135ds18 for the primary 3.5-inch floppy disk drive.


The format utility does not format floppies for use under DOS; use the dosformat command documented in doscmd(C).

UNIX systems require error free floppies.

It is not advisable to format a low density (48tpi) diskette on a high density (96tpi) floppy drive. Diskettes written on a high density drive should be read on high density drives. A low density diskette written on a high density drive may not be readable on a low density drive.

The device /dev/install is used only for installing and reading floppies. Attempts made to format this device may result in an error.

Formatting VHD 21MB disks in a floptical drive can take up to 30 minutes.


defines default device to format

floppy disk raw device files

floptical disk raw device files

See also

fd(HW), Sflp(HW)
© 2003 Caldera International, Inc. All rights reserved.
SCO OpenServer Release 5.0.7 -- 11 February 2003