H89 CP/M hard-secored boot diskette

From: Tony Duell <ard_at_p850ug1.demon.co.uk>
Date: Fri Apr 4 18:39:15 2003

> > I have, of course, dumps of the 2 proms (one is 32*8, the other 256*4) in
> > my Z90. They're a lot less 'unobtainium' than many chips I deal with!.
> That's good news, because I have a few CPU boards I'd like to upgrade... so,
> modern equivalent blanks are available? I haven't ripped labels off of any
> of them to see what they really are.

They _were_ standard PROMs, but I think that blanks are going to be
rather hard to find now. There must be something that can be kludged in,

> > > Tony, out of curiousity, what are your versions of the various PROMs and
> > > EPROMs at U516, 517, 518, and 520 on your Z90?
> >
> > That would involve getting to the Z90, which is not going to be
> > trivial....
> LOL! Sure, just curious. I want to confirm my suspicions that this '89 I'm
> using has been upgraded to the equivalent of your '90, but I'll take it on
> faith. If I can get that soft-sectored controller going, then it's
> equivalent enough for me. But hey, wasn't this the thread where two days
> ago, everyone was talking about how easy it was to open cases and build
> cables? ;-)

If I could get to the machine, it would be trivial to pull the boards
(I've taken this machine totally apart in the past, and can remember how
to do it). The problem is that there's a lot of stuff between me and the

Received on Fri Apr 04 2003 - 18:39:15 BST

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