My PhD supervisor[1]'s work as a student was on CSIRAC, which he would trot out at me whenever I talked about performance issues in the code I worked on for him or the crappy PC the department had given me. "Back in my day, I had 128 bits of memory to work with... made of mercury" (I recall him saying words to that effect, but CSIRAC had 768 words, so either my memory or his was playing up)

[1] Rex Whitehead, 1937-1921. He was at University of Melbourne late 50s/early 60s when CSIRAC was there.

I loved the detail about the hooter. It was just a way to hear when a program had finished, but Geoff Hill had to fight the mercury memory timing to get those blips landing regularly enough to make a tune. I can't stop thinking about that jump from a debug signal to Colonel Bogey.

Obligatory: https://youtu.be/ClSnMCTkBpw