Yep. Back then it was a form of non-volatile memory. Maintained what was on
it after power off.
Ken
On Tue, Apr 25, 2023 at 9:38 AM Paul Koning <paulkoning(a)comcast.net> wrote:
On Apr 25, 2023, at 9:25 AM, KenUnix via cctalk
<cctalk(a)classiccmp.org>
wrote:
Rod,
Never heard the singing. Switch room's were too noisy.
It always amazed me that those core planes were hand wired. I guess by
little people. Or, big people with little hands.
People (often women I think) with steady hands. I think the setup used a
work surface with notches in it corresponding to the positions of each
core. They would pour a cup full of cores onto that and use gentle shaking
and vibrating to get all those notches filled, then pour off the excess.
Next, threading the cores much like you thread a needle -- except that the
wire is stiffer than thread and thus easier to make it go straight through.
One wonders if this could have been done by machine. Probably yes, but
given the volumes involved I suppose the capital investment wasn't
justified.
The more amazing kind of hand-wired core is core ROM, where the wires
weave in and out of various cores according to the required bit pattern.
Getting that right seems like a far more complicated craft.
paul