> On Dec 7, 2020, at 2:50 PM, Van Snyder via cctalk <[email protected]>
> wrote:
>
>> ...
>
> One of my friends changed the tables in a 1620 to do octal arithmetic,
> for telemetry processing.
>
> Speaking of those tables, do you remember why the 1620 was called
> CADET? Not because it was a "beginner's" or "novice" computer. It was
> an acronym for "Can't Add; Doesn't Even Try."
The Model II added hardware add/multiply.
> The Computer History Museum in Mountain View, California has a 1620
> that worked for a time. They had a problem with cooling the core
> memory, which they could probably repair.
Or perhaps heating. I remember that our college 1620 Model II needed a couple
of minutes after power-on before it would be willing to operate; supposedly
that time was spent waiting for the heaters in the core memory to bring it up
to operating temperature.
Apparently timing and/or signal levels in core memory are fairly sensitive to
temperature, so keeping them consistent is helpful. It isn't common to select
a temperature well above ambient and use heaters to do that, but it isn't
totally strange.
paul
