At 16:54 13.08.2005 -0800, Jaap van Ganswijk wrote:

Just to make sure: Does that mean that you can already
read all the sectors from the disk?

Yes, I can. I'm using the Catweasel floppy controller to do that, as normal floppy controllers can't read FM disks any more. These VERSAdos disks are even a weird mixture of FM and MFM sectors, with 16 128-byte FM sectors on track 0/side 0, and 16 256-byte MFM sectors on all other tracks. I haven't seen an FM-track on a 3.5" disk before, and I've seen *many* disks in the past nine years. Luckily, the checksums are all CRC-16 according to CCITT, so once I found out about the basic format, the rest was easy.

So what you are looking for now is a way to interpret
the file system on the disk?

Correct. I have no clue what VARSAdos is related to - some CP/M or early DOS? I only know that the volume name of the disk can only be 4 characters, and that's stored in the beginning of very first sector of the disk (that is, the first four bytes of my image file).

Thanks for your other hints - I have also seen quite a few filesystems before, but never really tried to hack one. One way or another, I managed to get hold of a documentation, so I had the positions for sector pointers, directory entries and so on.

Perhaps you should make a dump of the disk contents
and give us (or some of us) access to it?

Sure, I can do that. Need to ask the owner of the disks first, but I guess that's not a problem, since the disks have been formatted for this purpose.

When the file system is very complicated, sometimes
it is best to emulate the complete original OS on a
modern PC and map a harddisk file as a quasi floppy
drive.

That's what I recommend t most of my customers, and it works fine for those systems where an emulator exists - especially the popular ones like C64, Amiga, Atari and Apple. However, I haven't seen an emulator for this 68K-based realtime operating system yet, and I doubt that it really exists. Any hints welcome...!

ciao,
--
Jens Schönfeld

--
Author: Jens Schoenfeld
 INET: [EMAIL PROTECTED]

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