This is a photograph of a core storage cabinet. It contained 256KBytes. There is more about it at 360 Core Storage.
Our interest here is the rectangular white panel at the top right. We still have it!
Just in passing, below it is power supplies, to the left of that two gates opened each containing 64KBytes of core storage, there were two more gates on the other side. In between was a central fixed gate containing circuitry common to all four gates.
| Mus.Cat. NEWUC:2005.77 | Mnfctr: IBM | Date: 1967 | Ser. No: - | Model: - |
| Comp: Control Panel | Height: 340 mm | Width: 470 mm | Depth: 158 mm | Weight: 625 g |
This is the panel. It displayed the state of 25 power supplies, power and high temperature indicators, and six rheostats for adjusting the voltages of the core storage modules.
This is the rear of the panel. At the top is two rows of indicators for the 25 power supplies
Below that is two rows of reed relays that controlled the seqence of powering on of supplies, and below that a mass of wires.
Here is that mass of wires. Go to Closeup to see the detail of the hand work involved in the construction of just this panel let alone the core storage gates.
One of the routine maintenance of the System 360/67 was to schmoo the three wire core storage memory. This involved varying the voltage of the "x" "y" and "z" wires to find a sweet spot. In this plot there is two plots a "." and an "X" plot. I do not know which came first, but enough to know that the core store needed tuning over time