Re: ADT122 and above?

[Andy McFadden <fadden@fadden.com>]

Bryan Villados <news003@macgeek.org> wrote:
> With that... It would be a really neat hack if someone is able to take an
> existing bit copier like Locksmith or Copy II+ and modify it. Instead of
> output the copied data to a destination disk, have the output sent to
> something else like a binary file or even a super serial card connected to a
> PC. That way, the output (including work-arounds based on the entered copy
> parameters) could then be sent someplace else, and later on in the future
> the recipient could feed the saved output back into the program and produce
> a disk. I'm sure the output wouldn't be compatible with any emulator at the
> moment, but this would be an excellent way of preserving your original
> copy-protected disks to something else (CD-R, etc.) other than copying it to
> another disk. My understanding of NIB is that it doesn't support things like
> 1/2 track copy protection and such.

What you describe is more or less what Saltine's Super Transcopy does,
i.e. it's a modified nibble copier that writes its output to a file.  In
this case, the "file" is written to two 5.25" disks in a peculiar format.
The only information in the output that doesn't end up in the NIB file
is which bytes are 9-bit or 10-bit sync bytes.  It would be easy enough
to modify CiderPress to leave them alone or tweak an emulator so that it
wrote NIB output with sync bytes marked, but that alone doesn't buy much.

What you need is to go a step further, and be able to support variable
track lengths for nibble-counting, variable track counts for disks
that have 36 (or even 40) tracks, half or "quarter" tracks, and track
synchronization.  It might be necessary to have a flag that indicates
9-bit vs. 10-bit sync bytes.

This will require software on the A2 side, updates to emulators, and a
new file format.  If you want to get carried away you could even support
nibble images of 3.5" disks.

The good news is that it would be easier to support in an emulator than
to actually write the data back.  It used to be that you'd sometimes
have to fiddle with your drive speed to get a nibble count right, and
of course *reading* quarter tracks is much easier than *writing* them.
You can store full images of each quarter track and read back exactly
what the drive sees, unlike actually trying to create a disk, where each
quarter-track stomps on its neighbors.

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