Ticket 01118

Yes: http://forum.kryoflux.com/viewtopic.php?f=2&t=790

It's one year later.... any news on this?

I will recommend this to the devs. 
Another option would be to build a separate converter for raw to DMK...

> Sorry for late reply. Does the DMK format allow data to be verified and
> described, e.g. defining gaps and their position, as well as the write splice?
> Or does it just store blobs of raw data which get stitched to a complete
> revolution in emulation, right at the point where the data starts?

Also sorry for my late reply ;)

The DMK format contains the full MFM-decoded track content plus all the positions in this track where there are MFM-encoding-errors (these are the positions where the sector header- and data-blocks starts, but I guess you already know this). This covers _all_ the information that can be obtained from a floppy disk when accesing it via a WD2793-like FDC (all MSX machines uses such FDCs or clones).

In other words using a floppy disk format that is even more low level than DMK will not result in any difference in emulation (more/less accurate) for MSX machines.

Compared to other disk image formats, DMK is a very simple format. And because it's a good fit for WD2793 FDCs, the FDC emulation code also becomes relatively simple.

So the DMK and IPF formats both have different goals (simplicity / preservation). It would be nice if there were tools to convert between these formats (or at least from IPF->DMK). It would be ideally if the KryoFlux software could directly export to DMK.

Sorry for late reply. Does the DMK format allow data to be verified and described, e.g. defining gaps and their position, as well as the write splice? Or does it just store blobs of raw data which get stitched to a complete revolution in emulation, right at the point where the data starts?

Because DMK supports enough to handle all MSX floppy disks (and a little bit more, but not MUCH more). So, it's a lot less complex to work with in an emulator like openMSX.

Why not simply use the IPF format that's been developed for software preservation purposes instead?

Hello,

First of all, thanks a lot for your preservation contribution!

I'm a member of the MSX community. A common format is a plain sector dump ("DSK"), but as you are well aware of, it doesn't support any non-standardness. On MSX many disk games were copy protected using several tricks; but all tricks would have to be compatible with the floppy disk controllers used on the MSX systems of course (mostly WD2793 compatibles and the TC8853AF).

In our MSX emulator "openMSX", we started to support the DMK format. Although this format is on a lot higher level that the magnetic flux, it is able to support all copy protections known to exist on MSX. So it can handle cylinders with a varying number of sectors, interleaved sectors, double sector indices, etc.

That's why I think it would be worth while having support for KryoFlux software to write to this DMK format. It would mean that copy protected disks for MSX (and probably many other systems) could be dumped with KryoFlux and exported to DMK format to be directly used in openMSX. Plus, of course, with the DMK format, the disk information is 100% preserved (as any other variations would not be accessible through the used floppy disk controllers on MSX, there is no other variation used in those original disks...)

Soec information about the DMK format is here: http://web.archive.org/web/20110611082358/http://www.trs-80.com/wordpress/emulation-dmk-format/

If you have any questions feel free to e-mail me back.

Kind regards,

Manuel Bilderbeek