For those who don't know what core memory is, it's miniature ferriteSome corrections of fact, which I will share with you privately.
beads strung together with three wires through them to read/write
[magnetize and demagnetize], and reset if I remember correctly. I have
seen 16 MB of core memory, it was the size of a full size tower case.
You can research and post; it is always better to correct yourself
than have someone else do it publically.
The three wires in a core memory are X select, Y select, and sense.
The cores work by pushing an X current and a Y current through an
intersection; two currents pushed the hysteretic toroidal magnetic
core past a threshold, either causing it to flip magnetic polarity
(generating a little voltage blip on the sense line) or not, depending
on previous magnetization. After flipping a core during a read, you
had to schedule a reverse set of currents on the same X and Y wires to
put the core back. The size of the arrays were limited by the number
of cores you could put on a sense wire before accumulated noise made
A friend in high school wanted to build a core memory, and wrote a letter
to Honeywell. They sent him a one pound jar of 15mil cores. All out
of spec, as near as we could measure.
What you probably saw was a 16*K* byte memory, the boards from the late
60s were typically around 16K bits, 8 boards to a byte, and about as big
on a side as a tower case with the small scale integration driver chips
around the sides of the core fabric. A 16MB machine would have been
gargantuan, indeed; I would guess 100 or more 19inch racks, 8 feet tall,
and probably costing on the order of $50M in current dollars.