Working with real disks

A familiar file browser, with a real drive at the other end.

FatFloppy uses Greaseweazle to read and write supported floppy disks. Once a disk opens, the directory tree, file viewers, and extraction controls work much as they do with an image.

On this page: Supported media | Connections | Opening a disk | Copying it out | Writing files

Which disks can go in the drive?

Direct hardware access currently covers FAT12, CP/M, and HDOS on soft-sectored FM or MFM media. FatFloppy offers 3.5-inch, 5.25-inch, and 8-inch drive sizes; the drive, cabling, power supply, and disk format must agree.

Media	Current route
Soft-sectored FAT12, CP/M, HDOS	Read and write through Greaseweazle using a supported FM/MFM layout.
Hard-sectored Heath H17	Open an .h17disk image. Direct reading of the original hard-sectored disk is not supported.
Commodore	Use D64, D71, or D81 images. Commodore 5.25-inch GCR disks are outside FatFloppy's current hardware support.
DEC RT-11 and Apollo DOMAIN	Use disk images. Their filesystem support does not imply direct access to the original media.

The full formats and machines guide separates image support from hardware support.

Connect the drive

You need a Greaseweazle interface, a compatible floppy drive, the appropriate ribbon cable and power connection, and a USB connection to the computer. Follow the Greaseweazle hardware guide for your board and drive; it links to the separate V4 setup instructions. Power requirements and drive selection vary between setups.

On Linux, USB access may require the Greaseweazle udev rule. The FatFloppy installation instructions show how to install it and reconnect the device. Greaseweazle's own software installation guide covers host setup and connection checks.

For a disk you want to preserve, engage its write protection before browsing. Keep an image of valuable media before experimenting with file changes.

Open the floppy

1. Insert the disk and click Open Floppy, or choose File > Open Physical Floppy.
2. Under Drive Interface Type, select IBM PC (A/B) or Shugart (0-3) to match the cable and drive setup.
3. Choose the Drive and Drive Size.
4. Leave Format (optional) at Auto-detect for the first attempt, or select the known profile for the disk. Custom... exposes geometry and encoding parameters for unusual layouts.
5. Click OK. Once the disk opens, check the detected format, geometry, and filesystem in Disk Information before working with its files.

FatFloppy finds the Greaseweazle device automatically. If the dialog says No Greaseweazle device found, it disables OK; check the USB connection, host software, and access permissions before reopening the dialog.

If a familiar disk gives an implausible directory or capacity, check the drive selection and try its known format profile. A 5.25-inch disk alone does not tell the program how its tracks were recorded.

Copy files, or save an image

To recover a few files, select them and click Extract. Choose a destination on your computer and let the read finish. You can inspect text and binary files with View File first.

To save the disk's decoded sectors, choose File > Save As..., enter a new filename, and choose a compatible output format such as IMG or IMD. After a successful export, FatFloppy opens the saved image. You can continue browsing that copy with the drive disconnected.

This produces a sector image. For preservation that includes the original magnetic transitions, use Greaseweazle's flux-capture tools and keep that capture as well. A sector image contains the decoded data and whatever metadata its container can represent.

Writing files back

For writable media, open the physical disk and use Add File, Delete, or the text editor's Save Changes. These change the disk in the drive. Wait for the operation to finish before removing the disk or disconnecting the hardware.

The Greaseweazle driver reads the rest of a track before changing it, refuses a partial-track write if untouched sectors could not be recovered, and checks writes by reading them back. An unfamiliar drive and format are best tried with a spare disk first.

Create Image creates a file on your computer. To put a complete image onto a floppy, use the Greaseweazle tools for the format concerned.

For everyday file operations and the difference between Save As... and the text editor's Save Changes, see Getting started.