Hand-wired core for ROM?

Chuck Guzis cclist at sydex.com
Fri Apr 10 10:43:31 CDT 2015

On 04/10/2015 07:54 AM, Dave G4UGM wrote:

> Rather than cores I believe that some machines had coils with drop in
> ferrite slugs. I found this patent from 1972 which references IBM
> Patents..
> http://www.google.co.uk/patents/US3691541

Somewhere on the web, there's a good exposition S/360 microcode store. 
Two systems (at least) used--one was capacitive (360/30 et al.) and the 
other was what was called "transformer" memory.  Very clever, both of them.

I believe that the CDC large machines used capacitor-type ROS.


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