Wire wrap?
Back in the 1980’s we dragged a prototype processor out of HW qualification in order to strap it to another processor so that we could demo a 2 processor benchmark. This was back in the day when mainframe processors were roughly the size of a refrigerator and composed of several dozen wire wrapped boards of discrete components.
The benchmark services people called me in on Friday evening because the dual processor system would not boot. It would fail on the first page fault generated.
I put an OS master mode breakpoint at the entry to the page fault routine so that I could print out the HW stack frame of the failing page fault. The hardware engineer came over to examine the stack frame where we located the bits in error.
He left to examine his wiring diagrams and came back with his wire wrap gun. A couple of ‘zip’ ‘zip’s later, and we were booting.
And then there was the fun of tracking down a problem that was caused by a tiny bit of bare no. 30 wire lost in the forest of pins, or finding a wrap that looked perfect, but the wire had snapped.
Fun times!