Plane of core memory

Curious Marc curiousmarc3 at
Fri Apr 19 01:45:06 CDT 2019

I believe 3 wire memory was first introduced by IBM in their 360 systems, and it was a very large development effort. They would almost certainly have patented their way to do it, but I have not checked.



From: cctalk <cctalk-bounces at> on behalf of "cctalk at" <cctalk at>
Reply-To: Jon Elson <elson at>, "cctalk at" <cctalk at>
Date: Thursday, April 18, 2019 at 7:08 PM
To: Noel Chiappa <jnc at>, <General at>, "cctalk at" <cctalk at>
Subject: Re: Plane of core memory


On 04/18/2019 03:15 PM, Noel Chiappa via cctalk wrote:

      > From: Jon Elson


      > As soon as somebody figured out that you could combine the sense and

      > inhibit wires, everybody immediately went to 3-wire planes.


I"m suprised the idea wasn't patented. Or maybe it was, and they made the

license widely available at modest terms?



I was thinking the same thing, but can't find any references 

to who invented it.  it certainly sounds like the sort of 

thing to get a patent on.


Point of interest, my freshman advisor was Bill Papian, who 

was Jay W. Forrester's grad student when he invented 

coincident-current core memory.




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