core... more

Well thanks to John D. I have a bunch of cores from the early 60s. They are roughly 50mils x 11 mils x 15mils. Cross section of the doughnut is rectangular at 15x11 mils. The reason for such rough measurements is my vernier is only good to .001" and I'd need somthing fancier to be more accurate. By eyeball the 8e cores are smaller! Based on several articles I've read theses will need about 400->600ma to switch and will do so in under 4uS. I will have to test this in a jig. Since the hole is ~20mils several #40 wires should pass through it easily. A simple core frame would be 8x8 (64 bits) and use a 4 wire system as that simplifies the select, inhibit and sense hardware. I'd likely go with late 70s level TTL and transistors to drive these and to sense the outputs I don't know if I'll use transistors (1968 or earlier designs) or comparator chips (aka 1540, 710, 711) will be used. They would also be consistant with 1970s technology. The goal if I can get the time is a 64x8 or 64x12 memory. Not large but enough. Why 64? becuase 1 of 8 decoders were common even in 1970, and the larger the array the more noise from switching. So 8x8 is manageable. Allison