plated wire memory

dwight dkelvey at
Sun Oct 20 15:50:44 CDT 2019

It is funny that the most common memory used today is a DRO type memory. The read destroys much of the charge on a DRAM cell, requiring a write back of the data.

From: cctalk <cctalk-bounces at> on behalf of Jon Elson via cctalk <cctalk at>
Sent: Sunday, October 20, 2019 10:22 AM
To: Nigel Johnson <nw.johnson at>; General at <General at>; Discussion@ < and Off-Topic Posts cctalk at>
Subject: Re: plated wire memory

On 10/20/2019 09:45 AM, Nigel Johnson via cctalk wrote:
> I remember an IBM engineer talking about this at our ham
> radio club. The wire was coiled inside a drum and pulses
> were sent down the wire.  The 'read head' was  a magnetic
> pickup at the other end of the coil - and access time was
> however long it took the pulse to arrive at the other
> end.  Therefore storage capacity was inversely
> proportional to data quantity, however at that time I was
> working with 660kB Univac FH330 drums for swapping and the
> 2-ton Fastrand for 164kB of long-term storage, so it has
> to be taken in context!
No, that is acoustic delay line memory, and is a serial
access type of data storage  All data is lost if the
equipment is powered down. Plated wire memory is a
random-access type of memory using principles similar to
core memory, except the magnetic material is a magnetic film
plated onto the copper wires.  There are a few other forms
of NDRO such as Biax that use cores with two holes in them,
one for the sense/inhibit wire and one for the select wires.


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