40k Ferrite Memory Core

[Tom Uban]

Brent Hilpert wrote:
> Pete Turnbull wrote:
>> On 29/10/2008 05:23, jim s wrote:
>>> I counted 52 wires x 52 wires in the top plane
>>> I counted either 20 or 19 total planes
>> I count 50 x 40, and 20 planes.  I think you need glasses, Jim :-)
>>
>>> In looking at the photo, it appears that there are 2 of those wires thru
>>> each core, so this is 26*26*20 or 13520 bits total
>> I only see one X and one Y plus the sense wire through each core (and
>> the cores are laid out like that), so I make it 2000 x 20 = 40000.
>>
>>> The connector marked X has 40 conductors.  I would assume there is also
>>> a Y connector, and maybe fewer sense lines?
>> 5.jpg shows 50 Y connections.
>>
>>> maybe only 1 sense line per plane?
>> That's normal.
> 
> My read on this is it's a (X=40)*(Y=48) matrix, going by the number of pins on
> the X&Y connectors, with 21 planes. I count 52 pins on the Y-side of each plane
> of the actual matrix. This makes sense as the extra 4 pins (52-48) would be 2
> for the sense line and 2 for the inhibit line of each plane. (The sense and
> inhibit connections do not come out to the connectors, there would have been
> additional wires connecting down the stack when installed). In
> http://www.thegolfballshop.com/oct28/3.jpg, one can see there are 4 wires
> through each core: X, Y, sense (diagonal), and inhibit (parallel to X), making
> it a pure 3D, 4-wire construction (the loopbacks for the inhibit lines are also
> visible). 
> 
> Given other aspects of it's construction (in part, the diagonal sense line) I
> think a 3-wire setup would be have been problematic or impossible.
> 
> It does give the impression of being 50's-era construction, probably from a
> tube machine.
> 
> Very pretty, I hope it doesn't get broken up, as intact 3D-stacks like that are
> pretty rare these days.
> 
> 

I agree about the hopes of it not being broken up.

When I see these, I always have the urge to want to create some logic to drive
it and to "see" it work. Not a particularly useful project, but interesting...

Thanks for your analysis!