Plane of core memory

[Dennis Boone]

 >   * 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)?

I'm having trouble figuring out what typical magnetic field strengths on
the cores would be, but I wonder if you could wave some ferrofluid over
individual cores and get movement.  Some ferrofluid particles are
apparently on the order of 10 nM in diameter, so wouldn't be all that
hard to move with a weak magnetic field.

 >   * 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.

Showing the read pulse and sense transition waveforms on a 'scope might
be of some interest.

De