[sebhc] diskette drive

Dwight K. Elvey dwight.elvey at amd.com
Mon Jun 7 15:14:22 CDT 2004

>From: "Patrick Rigney" <patrick at vintagecomputermarketplace.com>
>That reminds me of a question I keep forgetting to ask: are the busses in
>the H-8 and H-89 at all compatible?  Could a card be designed to work for
>both?  I know that each had its own version of the H-17 controller, yet they
>share the 444-19 ROM.  Aside from the difference in form factor, how
>different are they?  (I don't have an H-8; yes, I'm a loser, I know. I'm
>working on it.)

 Software wise, it should work but the H89 uses simpler bus
addresses that are reduced to a few selects. Of course the form
factor of the boards are completely different. My image loader
that ran on the H89 ran on the H8 with the H8-4 board. Other
than the monitor ROMs they did try to keep things similar.
 I do remember writing a 4 byte loop that should be able to
stay up with the floppy. It was for a 8 inch so it should
work for a 5-1/4 double density. Now, if I could just remember
how that code worked. I've long since lost where I put it.

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