Feature request: extend standalone desktop-side ucp and fsck tools with ability to operate on +3 .dsk images formatted with Fuzix filesystem

[pawosm-arm]

As in the topic. One can format an empty disk image file in the Gotek interface attached to the real Spectrum +3, which operates on the +3 .dsk disk image files and then copy that file to the PC. Alternatively, one can patch FUSE emulator with this patch which fixes disk formatting capability of FUSE (still one needs to provide existing .dsk image file, e.g. created by one of libdsk-utils, as formatting a fresh image started by selecting "Insert New" option still produces faulty .dsk files). Such filesystem can then be mount in Fuzix, files can be stored, etc.

Unfortunately, there's no UNIX-desktop-side tools for handling .dsk image files holding Fuzix filesystem, similar to standalone ucp and fsck that currently can operate on a raw Fuzix filesystem only.

[EtchedPixels]

Turns out to be quite easy so added (needs testing for the libdsk cases)

[pawosm-arm]

I tried to use newly built ucp on some .dsk image (fuzixfs.dsk.gz gzipped for GitHub to be happy with it) formatted under Fuzix containing an file.txt file. Unfortunately, ucp can't handle it:

$ ./ucp fuzixfs.dsk 
Opening fuzixfs.dsk (offset 0)
panic: no filesys

[EtchedPixels]

You need to ucp libdsk:fuzixfs.dsk, although it would still have failed

I can now read your test image ('this is a file') with ucp. Some other stuff fails so I don't think we are quite there yet.

[pawosm-arm]

Seems very close, some things work, some things don't. Yet one thing I can't find in the interactive ucp tool: how to save the changes? E.g. I've created a directory and left the ucp, opened my .dsk image again, and the directory wasn't there...