I've only seen two types of cores. Though I'm sure there are many
others as I've never had a machine of my own which used it.
The Rods you speak of may be RUBY? Hold it up to shine light through
them. The ruby cores look mighty pretty.
Regards,
Jeff
-----Original Message-----
From: cctalk-admin_at_classiccmp.org [mailto:cctalk-admin_at_classiccmp.org]
On Behalf Of Rick Bensene
Sent: Thursday, February 06, 2003 11:38 AM
To: cctalk_at_classiccmp.org
Subject: RE: interesting find
I have a strong feeling that this is a ROM rather than RAM.
The rods form the core of a transformer. A bunch of 'word' wires
each have a few turns wrapped around the (probably
a ferrite material) rod in a clockwise or counter-clockwise to encode a
1 or a 0. Another winding around the rod is the sense coil. When a
current pulse passes through one of the word wires, a current is induced
into the sense winding. The induced current in the sense winding is
different, depending on which way the word wire was wrapped around the
rod. The current pulse in the sense winding is amplified and
discriminated (to 1 or 0), and presented as the output for that bit.
A number of similar architectures were were commonly used for read-only
microcode storage on computers and even calculators
until the mid-1970's, when IC-based ROM began to appear.
The HP 9100A/B calculators use a similar architecture, using
wire bobbins instead of rods, for a microsequence store.
The Wang 500, 600, and 700-series calculators also use a similar
architecture, utilizing "U"-shaped ferrite structures as the transformer
core, for microcode storage.
Definitely a neat old relic.
Rick Bensene
The Old Calculator Web Museum
http://www.geocities.com/oldcalculators
HP 9100B:
http://www.geocities.com/oldcalculators/hp9100b.html
Wang 720C:
http://www.geocities.com/oldcalculators/wang720.html
> -----Original Message-----
> From: cctalk-admin_at_classiccmp.org
> [mailto:cctalk-admin_at_classiccmp.org] On Behalf Of Thilo Schmidt
> Sent: Thursday, February 06, 2003 2:19 AM
> To: cctalk_at_classiccmp.org
> Subject: interesting find
>
>
> Hi,
>
> Last week I found something which I think may be an ancient
> NVRAM Module. Sadly I couldn't find any useful information on
> the web, except on this page:
> http://www.iser.uni-erlangen.de:8980/iser/servlet/Anzeigen45?i
nventarnummer=I0105
It uses rather large magnetic rods to store data (4x25mm).
The PCB is dated 1972 and it was probably used in a Nixdorf-Computer.
It's called Staebchenspeicher in german (maybe rod-memory in english?).
Does anyone have further information on this module?
bye
Thilo
Received on Thu Feb 06 2003 - 19:53:00 GMT