Takes me back to when I was working on Josephson junctions (JJ) as a student, I-V curves were the first thing we did when characterizing a junction. JJ I-V curves were tricky due to the hysteresis they have in the underdamped regime, so we had some pretty involved stepping logic to ensure we get the curve with the required precision.

That said today everything is pretty much digital, you have Acqiris/Agilent 1 GHz ADCs and all the measurements are done in software, but I still remember using my old 20 MHz HMAG oscilloscope in XY mode with a triangle voltage generator to plot IV curves in real-time. Good old times!