I doubt that any of the old stuff I have, much of which, incidentally is
older than the 21-year-old to which you referred, will run at that 10MHz
rate, though I once used an ordinary Z-80A at 12 MHz with a BUNCH of 2147's
(that's power-hungry, basement-heating, fast, static RAM). Unfortunately,
almost no peripherals would talk to it without half a dozen or so
wait-states. That was in a hand-wired application and not in an S-100,
where, although you can interface the processor, RAM, and ROM with just a
gate or two, the bus interface takes about a hundred. (not really, but quite
a few!)
If I go the route of hand-wiring something for the S-100, I'll probably use
one of the WD1002-series bridge controllers I still have lying about. I
once lived for about three years on my earnings from that little
daughterboard I made which had the Z-80 and a few (4) TTL MSI and SSI parts
on it. It provided an interface to a WD-100x-series HDC or HDC/FDC. That
way I don't have to go blind wiring all the parts. At my age, that's a
serious consideration.
First, though, I'll have to fire up that big, old, chassis with the 8" HDD
in it, since, though I had several and have bought several cases of beer
with the $$$ I got for the bunches of high-quality scrap aluminum they
yielded, I've never actually made one of the old SHUGART 1004's work. It
always seemed appealing, since it had exactly 256 cylinders, and if you use
32-byte sectors, they also have exactly 256 bytes. It seems made for the
Z-80's OTIR and INIR instructions . . . it's just that the 5.25" drives, for
which I was designing controllers at the time, and which had to be bought at
the time anyway, were so much easier to interface with the S-100 controllers
I already had. (I stole from everyone, an equal opportunity
reverse-engineer . . . ) It's spent a couple of winters outdoors now, and I
wonder if the fans will even work. I do recall, you couldn't hear the HDD
above the fans.
About ten years ago, Someone gave me several of the XCOMP STS board pairs,
but tuned for 8" rather than 5.25" drives' data rate. I imagine they spent
a lot of time in someone's desk drawer, in order to keep the boss from
learning he'd paid for yet another item they couldn't use. Those might be
interesting to try out.
Dick
-----Original Message-----
From: Allison J Parent <allisonp_at_world.std.com>
To: Discussion re-collecting of classic computers
<classiccmp_at_u.washington.edu>
Date: Thursday, April 01, 1999 5:36 PM
Subject: Re: Rebirth of IMSAI
><I'm just about to consider firing up one of my old CP/M S-100 boxes just
fo
><spite and to see if I can get it to run the way I want. It starts with
><wanting the CPU board, and I'll probably have to try several, to run the 8
><MHz Z-80H I still have lying about somewhere. Then I want to run the 8"
>
>I say go for it.
>
>FYI, Murph the NS* horizon turned 21 this year. It's NS* box, and cpu(_at_
>8mhz), compupro ram, my 765 based floppy and a Teltek MFM controller.
>
>I also have a compupro with 512k of static runnign at 6mhz.
>
>the killer system however is using a 84c050 z80/10mhz, MMU with 512k static
>ram (no waits) smart floppy and smart HDC. The floppy and hdc system are
>8085 powered and have their own DMA (Ieee696 TMA) interfaces. I started
>that system back in 81 and for years it was the PC killer.
>
>Allison
>
Received on Thu Apr 01 1999 - 20:00:01 BST