plated wire memory

I worked at Univac Defense Systems in the early 70's. The launch control computer for the Minuteman was made by Univac. It had plated wire memory. I remember when the failure analysis group had to analyze a module that failed in the field. The module was locked in a safe and someone had to boost their clearance level to work on it. In plant 1, in Saint Paul, MN near the Mississippi River, there was a thin film memory production facility. It produced the memory used in the S3A submarine hunter (an/ayk-10 if I remember correctly). The bit planes were made from etched glass that had metal sputtered onto it, with tons of tiny holes for the word wires. The bit planes were stacked and the word wires were threaded through the tiny holes perpendicular to the planes. Because I sometimes worked out of plant 1, I had to take safety training for hydrofluoric acid which was used to etch the glass. Nasty stuff.