Plane of core memory

I don't believe there is a simple non-destructive way to read the state. If you could remove the cores, I believe you could put each core in a weak magnetic field. As the field passes from side to side, one should be able to determine the direction of the saturated cores because one side would allow more of the field to enter the core while the other side would act as non-magnetic. As for reading the data, you'd need to experiment to determine the minimum current that particular core required to flip a bit. With careful adjusting, I suspect one could sample the first bit. Once knowing the levels used, the entire array can be read. Dwight ________________________________ From: cctalk <cctalk-bounces at classiccmp.org> on behalf of Jim Brain via cctalk <cctalk at classiccmp.org> Sent: Thursday, April 18, 2019 10:19 AM To: cctalk at classiccmp.org Subject: Re: Plane of core memory I am the enviable owners of a plane of memory (procured a few years back at VCF-East, when there were a bunch of 32K? boards int he consignment pile. (Sorry, not currently interested in selling :-) But, I am thankful for the links, as I have wanted to interface this with a CPU or PC of some kind. A few questions, though: * Is there a way to "read" the core non destructively using any kind of passive method (I know, it would be tedious, no doubt, but I just feel like I should "backup" the core before I go messing with it)? * Along with the above, might there be a way to extend the passive read to be a worthy "exhibit" I could take to shows? Core memory is impressive just to look at, but reading it out using the PC and displaying the contents is so easy to fake that I think people will assume the core memory is not really being used. Some way of showing the actual magnetic changes in a small matrix (the large plane I have is probably not a good candidate unless there is a way to show such minute cores fields) would I think make the exhibit far more interesting, especially if I arranged the grid in a square and created a really slow version of something like "Tetris" on the plane. Ideas appreciated. Jim