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 <[email protected]> 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.pdf > > --Chuvk > > >
