I worked with a medium-sized analog computer in the mid 1970s. It may have had around 20 op-amps, covered a desktop, and used an HP XY-plotter for output. I cou

I worked with a medium-sized analog computer in the mid 1970s. It may have had around 20 op-amps, covered a desktop, and used an HP XY-plotter for output. I could set up different models of differential equations. I remember simple harmonic oscillators and predator-prey models [0]. I was studying physics rather than computer science and didn't then know about Turing computability. I found the GE BASIC timesharing system easier to program and use than the analog computer, but the graphical output of the analog system was much nicer. [0] https://en.wikipedia.org/wiki/Lotka%E2%80%93Volterra_equations https://en.wikipedia.org/wiki/Lotka%E2%80%93Volterra_equatio...