fdformat

fdformat [-n] [-f] [-F] [-V] [-v] [-t tracks] [-s sectors] [-S steps] [-H heads] [-b file] device

-n
    Skip verification after formatting

-f
    Force format even if write-protected

-F
    Fast format: skip bad sector scanning

-V
    Verify landmarks even with -n

-v
    Verbose output

-t n
    Tracks per cylinder (default: 80)

-s n
    Sectors per track (default: 18)

-S n
    Steps per track (default: 1)

-H n
    Number of heads (default: 2)

-b file
    File with bad sector list

-y
    Disable confirmation prompt

-q
    Quiet mode, suppress messages

-h
    Show help

fdformat is a command-line utility from the fdutils package designed for low-level formatting of floppy disks on Linux systems. Low-level formatting involves writing the physical sector headers, synchronization fields, gaps, and marking defective sectors, which differs from high-level formatting that only prepares a filesystem. This process was essential for older floppy disks, custom densities, or damaged media, but modern factory-preformatted disks rarely require it.

Usage typically involves root privileges (sudo) and targeting a device like /dev/fd0. The command probes the drive for parameters or allows manual specification of geometry (tracks, sectors, heads). It scans for bad sectors unless disabled and verifies by default. Confirmation is prompted to prevent accidents.

Key risks include irreversible data loss and potential drive wear from repeated head movements. Mis-specifying the device can format the wrong media, such as hard drives. fdformat supports various formats like 1.44MB HD (80 tracks/cyl, 2 heads, 18 sectors/track), 720KB DD, or exotic ones via options.

Though largely obsolete with declining floppy use, it remains valuable for retro computing, data recovery, or embedded systems needing precise disk preparation.

Irreversibly destroys all data; requires root; risks drive damage or wrong device formatting; obsolete for most modern disks as factory formatting suffices.

sudo fdformat /dev/fd0
Format first floppy with defaults and verification.

sudo fdformat -n -f /dev/fd0
Non-verified, forced format.

/dev/fd0 or /dev/fd0u - 1st floppy drive (unpartitioned)
/dev/fd1 - 2nd floppy drive

Developed by Alain Knaff as part of the fdutils package in the early 1990s to overcome Linux kernel limitations in floppy handling, enabling advanced formatting and diagnostics for MS-DOS, Atari, and Amiga disks.

superformat(1), floppycontrol(8), getfdprm(8), mformat(1)