On Mon, Oct 10, 2016 at 6:42 PM, Fred Cisin <ci...@xenosoft.com> wrote:
> What Eric is working on is software that can decode disk formats that are
> NOT necessarily WD/NEC FDC compatible!  And writing a file similar to the
> one created by IMD.
> That will most certainly NOT then be convertible by IMD into a Victor 9000
> disk!

That's a good explanation.  I was thinking of it as non-standard use
of IMD format; the resulting IMD file would contain the logical
contents of the Victor 9000 disk, but because the IMD format doesn't
(yet) have suitable definitions for Victor 9000 format, the file would
purport to contain IBM-compatible MFM sectors.

I don't really have any plan for a way to convert these Victor 9000
pseudo-IMD files back into actual diskettes. I could write an
imdtoflux program as a counterpart to the fluxtoimd program, which
would help with a portion of the problem.

> However, OTHER software, that understands the file systems could then
> extract files.  For example, if it is successful, then it might be possible
> to take the Victor9000 IMD file produced by fluxtoimd, run it through IMD to
> write that content onto a disk in a WD/NEC compatible format with
> similarities of parameters other than encoding (eg. Chromemco?), and then
> read files from that disk using XenoCopy or equivalent.

I'm not sure how flexible XenoCopy is, but Victor 9000 format used
Zoned CAV, so tracks have varying numbers of sectors, from 11 to 19.
The pseudo-IMD file will preserve that organization. If the IMDU
program doesn't get upset by the variable number of sectors per track,
it might be able to extract the sector data into a raw binary
filesystem image. Assuming that MS-DOS on the Victor 9000 uses the
obvious mapping of FAT cluster numbers to track/head/sector, the
resulting raw binary filesystem image might be usable with existing
utilities for FAT filesystems, such as mtools.

There's always been such a bewildering variety of mappings of CP/M
blocks to track/head/sector that I wouldn't put any money on the same
conversion working for Victor 9000 CP/M-86 disks.

In both cases (MS-DOS and CP/M-86), if it proves necessary I'll whip
up another simple utility to convert the pseudo-IMD file into a usable
raw binary filesystem image.

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