I used to get a kick out of the recollections of the slightly older guy I worked with (Rob Weinberg). He used to tell me about programming on a system where they didn’t even have a keyboard. As he explained it, the computer was programmed by flipping switches for each bit and pushing a button to store assembly instructions. This would be done repetitively until all the instructions were entered into the computer and then the “program” could be run. I thought that was really funny having started with 4GL programming. Well I ran across a couple of videos on youtube of a guy programming a Dec PDP computer which was the machine that was in use just before I started my career on Dec Vaxen. And the videos show how it was done. (you younger guys might want to sit down before you watch this, I don’t want anyone to get dizzy and hurt themselves)
The switches allowed assembly language to be input (looks like 4 – 3 bit characters to me). They also had the ability to read programs off of paper tapes as long as you could enter the program to read the tape. Here’s a guy doing just that.
If you want to see what a variac is, have a look at this one:
It’s basically a power conditioner. I’m not sure why they needed that. I have seen people use them with guitar amps which can be sensitive (from a sound perspective) to low voltage or variable voltage.
Anyway, I thought the videos were entertaining.