27 Aug
2010
27 Aug
'10
10:36 a.m.
On 2010 Aug 27, at 9:36 AM, MikeS wrote:
----------------------Original Message:
Date: Fri, 27 Aug 2010 00:30:24 -0700
From: Paxton Hoag <innfoclassics at gmail.com>
Subject: Re: Burroughs core memory module <-> machine
To: "General Discussion: On-Topic and Off-Topic Posts"
<cctalk at classiccmp.org>
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<AANLkTik=GrMyH34cMQahxmPcSYoraFQ5+7bS=e2a=7dD at mail.gmail.com>
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I think I forgot to mention the date previously, component dates codes
are into 1979, somewhat late for core. LSI mem would have produced a
smaller module by then. Either it was some special-requirement system
or probably a legacy design/production issue.
It might have been used as a single module plugged into a backplane
with other system boards or with multiple modules plugged into a memory
bus.
High-end commercial construction (7400 series ceramic packages, 1%
resistors, etc.)
I have a core memory module from some Burroughs
machine. It is a large
plug-in PCB about 16 inches square containing address & inhibit
drivers &
such. Mounted to this is a near-same-size daughter-board containing
the
sense amplifiers and the folded planar array of cores underneath a
metal
shield.
It is organised as 32 KWords, 20 bits wide.
Any suggestions as to what machine this may have come from?
Burroughs made several successful solid state accounting machines
before branching to full computers. Some of these had core memory and
were made in the 1970s.
...
Paxton
------------------------Reply:
Indeed, specifically a few models in the E series, but those memories
were
*much* smaller; I think I still have one somewhere.
In the transition from mechanical base10 systems to solid state binary
systems some early E models used an interesting device called a "core
counter" which was effectively a non-volatile IC-sized solid state
magnetic
divide-by-ten counter that emitted a pulse for every ten pulses in, a
logically direct replacement for the mechanical cams and 10-position
gears
that most adding and accounting machines had been built around up till
then.
32K x 20 sounds like it'd be out of a Medium or Large system (B2xxx or
greater).