Analysis and recovery of IBM MFM floppy image data
This is where I experiment with methods to more reliably decode IBM MFM floppies based on flux transition data.
There are two source subdirectories: csrc/, the C++ version, and python/, the Python version. I'm currently working on the C++ version; the Python version is older.
To compile the C++ version, use cmake. A typical invocation would be as follows:
$ cd ~/Sources/
$ git clone https://github.com/kristomu/flux-analyze.git
$ cd flux-analyze
$ mkdir build
$ cd build
$ cmake -S ../csrc -B .
$ make
Then use by invoking flux-analyze by specifying one or more FluxEngine .flux
filenames on the command line. If more than one flux file is specified, they'll
be treated as different images of the same floppy.
To use the Python version, run mfm_decoder interactively in ipython, i.e.
ipython3 -i mfm_decoder.py, then invoke demonstrate("your-file.au"). The
Python version uses FluxEngine .au dumps as input. The README.md file in the
Python subdirectory contains more information.
The tracks/ directory contains some sample tracks in FluxEngine and .au format. The .au files are all compressed with bz2. (Uncompress before using.)
- low_level_format_with_noise: every sector is 0x00 or 0xF6. Some weird effects on the flux transitions in certain places. Useful for testing recovery ideas later, because the data pattern on the corrupted sectors is known.
- MS_Plus_OK_track - OK track from a Microsoft Plus! floppy. This one can be decoded fine with FluxEngine.
- MS_Plus_warped_track - Warped track from a Microsoft Plus! floppy. FluxEngine can't cleanly decode every sector, but both flux-analyze versions can.