Intel C8080A chip brings $565 on EBAY

From: Richard Erlacher <edick_at_idcomm.com>
Date: Mon Nov 19 10:58:37 2001

I'm not sure that the Econoram IV was one of the boards that used those 64k-bit
DRAMs. Did it? This alpha-particle issue didn't come up with the 4K and 16K
dram devices. It only surfaced when the density went up to 64K-bits and the
supply went to a single 5-volt Vcc. The first context in which I recall the
incidence of packaging-induced alpha-particle-hits causing a problem was with
64K-bit DRAMs. There was a component of this problem that was characteristic of
the device family, and was later mitigated by adding an XOR buffer (XOR-ing data
with one of the address lines) to the data to equalize otherwise random charge
distribution throughout the device. Needless to say, I was never convinced,
myself, that all the information about the then-new 5-volt-only DRAMs was on the
level, as much of it sounded like folklore. The fact that the industry went to
a logic fix suggests it wasn't without merit, however.

There were plenty of other reasons why various DRAM circuits didn't work
terribly well, most dealing with timing and buffering. Once the S-100 became
dominated by Z80's, the use of various features of the Z80, not present in the
8080 round which the bus was designed, began to cause interoperability problems
on the S-100, as a consequence of which it became advisable to have DRAM boards
that were either made or certified by the CPU maker. Several vendors made DRAM
boards that worked and played quite well with others, but Godbout/CompuPro was
not one of them. One couldn't even rely on those working with older Godbout
products in the system.

Dick
----- Original Message -----
From: "Douglas Quebbeman" <dhquebbeman_at_theestopinalgroup.com>
To: <classiccmp_at_classiccmp.org>
Sent: Monday, November 19, 2001 9:23 AM
Subject: RE: Intel C8080A chip brings $565 on EBAY


> > 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 - 10:58:37 GMT