rectangular sense core vs. diagonal

Jon Elson elson at
Wed Jun 7 12:01:36 CDT 2017

On 06/07/2017 09:12 AM, william degnan via cctech wrote:
> Where there any computers that used a "rectangular sense" core RAM?
> Whirlwind core is diagonal.   This page describes the differences/evolution
> of the sense line.
> More:
> Were rectangular core planes used in any commercial/government computer
> that saw production activity, presumably the period 1953-1959?    Whirlwind
> is known for diagonal sense planes, but was there a brief period when the
> core was "rectangular sense"  I know core was added to Whirlwind as an
> upgrade, it did not launch into production with core.  (right?)
I think IBM LCS on the mid-scale 360s were rectangular.  I 
assume by rectangular you mean that all wires were on a 
rectangular grid, parallel to the select wires.  The google 
article on core memory shows a CDC 6600 core plane that 
shows no sign of diagonal wires.

I think many old core planes with big cores ran all wires on 
a square grid, as there was plenty of window area in the 
cores.  When they went to smaller cores and combining the 
sense/inhibit winding, then the diagonal wire threaded more 
easily through the remaining window after the X and Y select 
wires were in place.


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