Plane of core memory

Eric Smith spacewar at
Sat Apr 20 02:03:05 CDT 2019

On Fri, Apr 19, 2019 at 5:46 AM Noel Chiappa via cctalk <
cctalk at> wrote:

> where the description of the invention of 3-wire core can be found on pg.
> 231; it was invented by a group of engineers, based on a similar idea used
> in
> Stretch. There is indeed a patent, No. 3,381,282, with six names on it. IBM
> must have licensed it, but there is nothing on that.

Under section XI of the 1956 consent decree, IBM was ordered to provide
non-exclusive licenses for any of its existing or future patents to anyone,
though "a reasonable royalty may be charged". They probably licensed the
'282 patent to many parties.

More famously, the consent decree required that IBM make machines available
for purchase (rather than only for lease), and make service and parts
available for machines they had sold. As the result of a 1996 settlment
with the Justice Department, the 1956 decree terminated with respect to
various product lines from 1996 to 2001.

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