3 Feb
2023
3 Feb
'23
7:07 a.m.
Chuck, the CDC 7600 duty cycle integrator is really a work-around against
overheating and has nothing to do with core reliability and/or endurance.
Core and the data stored in it lives "forever" if the operating constraints
of the medium are adhered to (temperature being one of the constraints).
The 7600 was able to push core access past these constraints, hence needed
the duty cycle integrator. Different physical design and/or better cooling
could have been alternatives, but the duty cycle integrator was an easy fix
once the machine was out in the field and core memory started failing due
to overheating.
Core written in the 60s would read just fine today unless something
external to it destroyed the data.
Tom
On Fri, Feb 3, 2023 at 2:12 PM Chuck Guzis via cctalk <cctalk(a)classiccmp.org>
wrote:
On 2/2/23 21:23, Tom Hunter via cctalk wrote:
The actual ferrite core doughnuts do not break
down with continued use,
BUT
moisture or mechanical impact or vibration will
damage or degrade the
ferrite cores. Otherwise the ferrite doughnut will live and maintain its
properties "forever".
Well, I don't know about that. The CDC 7600 had issues with core
overheating and included a "Duty Cycle Integrator" on core. See PDF
page 51, page 2-24:
http://www.bitsavers.org/pdf/cdc/cyber/cyber_70/60367200D_Cyber70-76_Jul75.…
--Chuvk