According to BGB <cr88192@gmail.com>:

We used the 11/20 as a remote debug device for the 8085 cash
register machine(s) we were building.

Core memory: slow to access but also slow to forget.

Core memory was before my time, but I remember reading somewhere that it >needed to be preheated to a certain operating temperature in order to
write to it (because the hysteresis energy of the ferrite rings was >temperature dependent, and it needed too much power to flip the bits at
lower temperatures).

The memory for the IBM 7090 in the late 1950s was in a heated oil bath
but they soon figured out how to make core work at room temperature.
On the PDP-8 and PDP-11's that I used, the core was in the box with
everything else with no special temperature controls.

--
Regards,
John Levine, johnl@taugh.com, Primary Perpetrator of "The Internet for Dummies",
Please consider the environment before reading this e-mail. https://jl.ly

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On 10/11/2024 12:40 PM, John Levine wrote:

According to BGB <cr88192@gmail.com>:

We used the 11/20 as a remote debug device for the 8085 cash
register machine(s) we were building.

Core memory: slow to access but also slow to forget.

Core memory was before my time, but I remember reading somewhere that it
needed to be preheated to a certain operating temperature in order to
write to it (because the hysteresis energy of the ferrite rings was
temperature dependent, and it needed too much power to flip the bits at
lower temperatures).

The memory for the IBM 7090 in the late 1950s was in a heated oil bath
but they soon figured out how to make core work at room temperature.
On the PDP-8 and PDP-11's that I used, the core was in the box with everything else with no special temperature controls.

And in the late 1960s and early 1970s the Univac 1108s and the IBM S/360
models 30 and 65 that I worked with worked just fine in the typical
cooled computer rooms of the day (IIRC high 60s degrees F)


--
- Stephen Fuld
(e-mail address disguised to prevent spam)

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