25 Jan
2023
25 Jan
'23
7:43 a.m.
I have an Ampro Little Board Plus, which is a
single-board Z80 computer
the size of a 5 1/4" disk drive. The "plus" means it has a SCSI
interface. A couple of years ago I was planning to build a flash disk for
it and dug through a lot of specs and bios code. Original SCSI was almost
identical to SASI and they were often interchangeable. The protocol is
rather simple, as you stated. What I found in the Ampro bios code was that
for reading and writing only about 4 commands were used. Another small
number were used for formatting. I think, iirc, there were two types of
read and two types of write. I never got around to building the thing, but
it should be pretty simple. I would also be rather surprised if no one
else has done it. But if you have the P-2000 bios code, you could take a
look. I suspect it would be very similar to the Ampro code.
Alas there is no source of either the CBIOS or the boot ROM in any of
the P2000C manuals and I suspect such source was never released. But
it should be possible to kludge up something to do the SASI handshake
and see just what does come out of that port when I try to boot from a
hard disk or whatever.
-tony