At 08:45 PM 4/13/2022, Fred Cisin via cctalk wrote: >It certainly seems that it would be THEORETICALLY POSSIBLE, with an extreme >budget, to build a high resolution device similar to the 3M Magnetic Tape >viewer, . . . >https://blog.adafruit.com/2020/03/01/the-magnetic-tape-viewer-see-the-sound-on-a-tape/
And how often do those antique viewers come up on eBay and at what price? Modern ones are for sale for about $120: https://store.arnoldmagnetics.com/product/284/magnetic-viewer-b-1022 But you can't really use an optical method, right? You need to scan the field another way. And if you set a limit on disk platter tech to anything made before 1985, what's the magnetic resolution you'd need and what would you need to detect? Could the reconstruction be software-based, reconstructing from data gathered while scanning X-Y across surfaces using a mechanism not unlike a scanner or 3D printer? Or would you need to scan like the flying head that wrote the data back then? >So, I am making a 24" patio table out of it (under 3/8" tempered glass). >http://www.ed-thelen.org/RAMAC/RAMAC_Plaque_v40.pdf A rare item. How many others have you seen in the wild? - John