Hi, Commodore folks,
I have just tracked down an ISA IEEE-488 card and was thinking that it might
be interesting to use it to build an older PC into a Commodore diskette
drive emulator - I recall there are various projects to interface modern
hardware to PETs (like the C2N232 I have with me), but the idea in this case
is to allow existing apps to work as if there were a real C= drive hanging
off the PET's IEEE port. Essentially, the PC would act as closely to, say
a 4040, as possible. My thought was that if I had a real IEEE-488 interface,
it could handle the physical-layer protocol, and the emulator would only have
to handle sending and receiving command strings and data.
The virtual diskettes would be, of course, image files. I'm not really as
worried about RELative files - more along the lines of "direct access"
files where the code running on the PET wants to read and write individual
sectors, ignoring the C= DOS filesystem. That is, in fact, the major
reason for trying to emulate drives in the first place - if it was just a
case of loading and saving streams of data as files, the C2N232 does a fine
job of that (and costs on the order of $10 to breadboard).
There seem to be a number of ways to emulate C= IEC-bus devices (such as
the 1541-III), but not for the IEEE-488. If anyone can point me at any
existing projects, even if they are incomplete, it would be a big help.
Thanks,
-ethan
--
Ethan Dicks, A-333-S Current South Pole Weather at 30-Jan-2008 at 02:00 Z
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Ethan.Dicks at
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