Gee, Allison, that's not how I remember that stuff at all. We had a dozen or
more machines running a really thorough memory tests in the early '80's and the
purpose was to quantify the difference in error rates between ceramic and
plastic parts. In order to do that, all you needed was a big enough DRAM array,
and you'd see them at a rate of about one or two per minute from among those
machines. Of course we'd be using about 8 boards measuring about 16" x 22" with
288 devices per board, then tracking the locations of the corrected errors. If
you used plastic parts, the error rate dropped, comparatively, by about 90%.
That's the reason the problem was so widely discussed. It's odd that it doesn't
exist anymore, with the typcial home computer having about as much RAM nowadays
as all the computers in the world had when I was in college. BTW, that entire
problem went almost completely away once the DRAMs were redesigned with that
checkerboarding mod I mentioned.
Dick
----- Original Message -----
From: "Allison" <ajp166_at_bellatlantic.net>
To: <classiccmp_at_classiccmp.org>
Sent: Monday, November 19, 2001 10:31 AM
Subject: Re: Intel C8080A chip brings $565 on EBAY
> back then I was involved in that stuff and 99% of the Dram problems were
> design
> related and not alpha particle. To see the alpha particle in real apps
> you'd need
> a box that had thouands of them running 7x24 for weeks! S100 systems that
> ran
> that well were prone to the power company failing to deliver before ram
> failure was
> a problem!
>
> Back in that time frame I used static ram due to the general flakyness I
> preceived
> of most S100 cards. The best S100 ram I'd used for that time frame (1980)
> had an 8202( Netronics DRAM using 16Ks).
>
That board (I've still got a couple, 1 still unbuilt) was very, Very, VERY slow,
and used somebody's rather lame DRAM controller IC. The boards from CCS had
timing adquate for use with 64K parts if you didn't mind making the mod's, AND
they worked. The stock and unmodified version of those boards ran in a set of 8
boards for one of my clients running something like Mmmost or whatever it was
called, for several years and, since they had a UPS, never experienced a failure
in the time I worked with them. The Systems Group stuff worked really well, and
I still like 'em, though the boards are 512K boards rather than the 128K ones
they were then, having been designed with the eventual emergence of 256K parts
in mind.
The main problem with S-100 DRAM boards was that designers seldom understood
both the S-100 timing and the proper use of DRAMs. Frankly, since there wasn't
a standard, it is understandable that nobody could get complete interoperability
from DRAMs with reasonable timing, since the S-100 had been designed around one
CPU and then the most popular CPU was promptly replaced by another one with
completely different timing.
>
> Allison
>
>
> From: Douglas Quebbeman <dhquebbeman_at_theestopinalgroup.com>
>
> >> Back in the early days of 64k DRAMs, the COORS ceramics were described as
> >having
> >> too much radioactivity for use in high-density memories. I'm not sure
> that
> >was,
> >> in fact, the case, but somebody seems to have thought so. Do you suppose
> >they
> >> fixed that? Coors was a leader, in the '60's in porcelain tooling and
> other
> >> such oddities, not to mention having "perfected" the draw-and-iron
> process
> >for
> >> making thin-walled aluminum beverage cans.
> >
> >My 8k EconoRAM IV, one of the first S-100 boards to use DRAM, used the
> >very chips that supposedly had that problem. I've been told mine are
> >OK, but it used to be a bit flaky; however, I always blamed that on
> >the state of the early S-100 systems and my soldering work on the SOL
> >to which it was attached... I solder *much* better now... -dq
> >
>
>
Received on Mon Nov 19 2001 - 12:43:47 GMT