Re: S/360-50 microcode held in capacitors
The Model 30 microcode was as stated on 80 column punch cards with silver contact plates for each of the 80 by 12 location that could be punched out to change the code. They were held against the 'read' plate by air pressure. To update the microcode you had to deflate the bag and then remove and replace the necessary cards. The problems we had as engineers were that over time the silver on the card would stick to the base board which meant a major cleaning job and the other common problem was loss of pressure in the airbags that pressed them against the read plate. The model 25 I think had a loadable microcode from punched cards that had to be reloaded after every power down. The model 40 had TROS which was Transformer Read Only Storage on long flexible tapes stacked around transformer cores.
Biting the hand that feeds IT
