FatFloppy

There are still files on those floppies.

FatFloppy brings a familiar file browser to vintage disks. Open an image, read an old document, pull out a file, or see how the disk is laid out. With a Greaseweazle and a supported drive, you can work with real floppies too.

A Heathkit H17 CP/M image, with MOVCPM17.COM selected. View full-size screenshot · GIF, 347 KB.

Get FatFloppy 0.2.0 »   /   Take the visual tour

For Windows, macOS and Linux. Version 0.2.0 was released on 13 September 2026. FatFloppy is still alpha software; use copies of disk images when trying edits.

A file browser, with the disk underneath.

The directory tree and file list are the starting point. Beside them, a disk information panel identifies the container, geometry and filesystem. The map shows system areas, directories, used space and free space, with a highlight for the selected file.

Open a file to switch between text and hexadecimal views. Extract it to your computer, or add files and edit text on supported writable media. You can also create and format a new blank image for a supported machine.

More than DOS disks

FAT12, CP/M, HDOS, Commodore CBM DOS and DEC RT-11 all have read/write support in suitable image containers. Apollo DOMAIN backup sets and native SR9 AEGIS volumes can be browsed and extracted read-only.

FatFloppy examines the disk contents to identify the format, including many images without a standard boot-sector description. The container and filesystem both matter: a writable filesystem inside a Teledisk archive still opens read-only.

Find your disk in the format guide »

Find your way in

Start here	What you'll find
Visual tour	The disk map, file browser, and text and hex viewers, with two real examples.
Getting started	Choose a download, open your first image, and extract a file.
Disks & formats	Supported systems, image containers, and the limits that matter.
Working with real disks	Greaseweazle, drive selection, reading a floppy, and saving a sector image.

From the workbench

Some of the most interesting disks don't fit the usual assumptions: CP/M images without a known disk parameter block, DEC images stored in different sector orders, or Apollo backups split across several floppies. Those are the kinds of details I like working out.

For a closer look at one of these systems, read Dissecting the HDOS Diskette in the journal.