ufifmt

Format floppy disks in USB UFI floppy drives using PyUSB / libusb.

This is a Python rewrite of ufiformat, originally written in C.

Requirements

• Python 3.10+
• pyusb
• libusb 1.0
• pyudev (optional, Linux only) — enables device path arguments such as /dev/sdb or /dev/sg1, and shows device names in --inquire list output

Installation

ufifmt

git clone https://github.com/tedigh/ufifmt.git
cd ufifmt
sudo install -m 755 -D -t /usr/bin/ ufifmt

Or download a ZIP from GitHub and extract it, then run the install command above from the extracted directory.

libusb

# Debian / Ubuntu
sudo apt install libusb-1.0-0

# macOS
brew install libusb

Python dependencies

pip install pyusb

# Optional (Linux only)
pip install pyudev

Usage

usage: ufifmt [-h] [-i] [-f KB] [-V] [-F] [-v] [-q] [--version] [LOCATION]

Format a floppy disk in a USB UFI floppy drive.

positional arguments:
  LOCATION              device location (e.g. 1-2.3, /dev/sdb, /dev/sg1);
                        omit with -i to list all devices

options:
  -h, --help            show this help message and exit
  -i, --inquire         show device information instead of formatting;
                        omit LOCATION to list all devices
  -f KB, --format KB    format size in KB (default: use current media size)
  -V, --verify          verify after formatting
  -F, --force           skip safety checks
  -v, --verbose         increase verbosity (-v or -vv)
  -q, --quiet           suppress all non-error output
  --version             show program's version number and exit

macOS: eject the disk in Finder (or: diskutil eject /dev/diskN) before running.
Linux: run as root, or add a udev rule for the device.

Examples

# List all connected UFI floppy drives
ufifmt -i

# Show device and media information
ufifmt -i 1-2.3
ufifmt -i /dev/sdb        # requires pyudev

# Format using the current media size
ufifmt 1-2.3
ufifmt /dev/sdb           # requires pyudev

# Format to a specific size
ufifmt -f 720 1-2.3

# Format and verify
ufifmt -V 1-2.3

Supported format sizes: 640, 720, 1200, 1232, 1440 KB — available sizes depend on what your drive reports as formattable.

Linux Notes

The kernel USB mass-storage driver is detached automatically before formatting and re-attached on exit.

You may need to run as root, or add a udev rule to grant access without root:

# /etc/udev/rules.d/99-ufifmt.rules
SUBSYSTEM=="usb", ATTR{idVendor}=="YOUR_VID", ATTR{idProduct}=="YOUR_PID", MODE="0666"

Run ufifmt -i to find the VID/PID of your drive, then reload rules:

sudo udevadm control --reload-rules
sudo udevadm trigger

Installing pyudev and libudev enables device path arguments such as /dev/sdb or /dev/sg1, and adds a devices column to the --inquire list output.

macOS Notes

Before running, eject the floppy disk in Finder, or from the command line:

diskutil eject /dev/diskN

This releases the IOKit driver so libusb can claim the USB interface.

macOS support has not been tested. IOKit security restrictions may prevent libusb from claiming the interface even after ejecting. Reports from macOS users are very welcome — please open an issue with your macOS version, drive model, and any error messages.

Known Limitations

• macOS: untested; may not work due to IOKit driver restrictions.
• Device path arguments (/dev/sdb, /dev/sg1) require pyudev and are Linux only.

License

GNU General Public License v2.0 or later — see COPYING or https://www.gnu.org/licenses/old-licenses/gpl-2.0.html.