> On Apr 25, 2023, at 9:37 AM, Rod Bartlett via cctalk <cctalk@classiccmp.org>
> wrote:
>
> Ken,
>
> Core places being hand wired amazed me as well. The maintenance panels on
> the Honeywell mainframes were hand wired as well. They were works of art
> with lots of toggle switches and lights (the later models switched to LEDs).
> I could see most of the internal registers using a fancy scroll wheel to
> select what register the lights should show. I could also enter small
> diagnostic programs and single step through them using the panel.
>
> Most of our core memories were 256K of 36 bit words (with a few spares for
> each location). They took up lots of floor space. I suspect the fact that
> the power supplies had to drive that much equipment was what made them sing.
The biggest core memories I remember are the ones in CDC mainframes "extended
core storage" -- at U of Illinois we had a 2 MW config, 60 bit words plus
parity. Actually, ECS was organized as 488 bit words, with 6 µs access time, 8
way interleaved, for a transfer rate of 10 MW per second (matching central
memory). Nice.
That was an odd structure, it was described as "linear select" which I think
means an address line per word rather than the usual X/Y concident current
selection scheme. Pictures show a rectangular memory array; perhaps it was 488
bits high by some number (512?) wide but I haven't been able to find the
details.
paul
