A trip down memory lane.

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For a period of about 12 years I was lucky enough to have almost unresticted access to a local scrapyard. Although this yard did crush cars, it was not a specific car breakers yard - it dealt with everything, including computer and electronic stuff - I was generally on the lookout for wood / metal working machinery.

The board shown in the middle pic is a 20k by 6 memory board (I assume that's 120k bits, not bytes, btw - so 15k in current 'money' :)) that I found there. (Piece of white paper is 1 inch square, btw)

The interesting thing (imo) is that it's a magnetic core board, so the 24 rectangular sections in the middle of the pcb are dense areas of cores. LH pic shows a section of one of these areas and the RH pic shows a close-up of a few of the idividual cores - so you can clearly see the wires going through the centre holes in the (torus shaped) cores. This lot was apparently assembled by hand (!) - hence the reason memory used to be somewhat expensive, methinks?

Since I don't want to damage the board, using a steel rule and magnifying glass to measure an individual torus, I reckon they're about 0.25mm dia - or about 0.01 inch (10 thou) dia to any imperialists out there :) ...... approx 3 - 4 times the dia of a human hair (!).

Considering the size (and capacity) of a digital camera memory bd ............

Bd is an Ampex one, made in Hong Kong, 1978 - according to cover plate info.
If anyone interested:
Middle pic taken (today) with a Fuji 2600z digital, using ambient light and macro mode.
Other 2 pix taken with a Canon A1, auto bellows etc (can't remember lens as some time ago)