Re: Hot-plug
I was putting together a PC AT for a friend back when such things were $3500, and hard drives were full-height and multiple GB were rare. I think it might have been even pre-486.
We put the powered-on drive on top of the case, at which point there was a pop and it was an ex-drive.
Turned out a big old 1/2w resistor on the drive was destroyed, as evidenced by the smoke mark. Just for the hell of it, we replaced the resistor (this was long before surface-mount components) and the damn thing worked. It kept going for at least 3 or 4 years.