Before that PLUGBOARDS were used for programming - physically (wires) routing data signals between specific functional blocks of computers to do the different parts of the required calculations.
The memory programmable systems like this one were still VERY primitive and had less calculating power than your watch. They STILL performed at a workrate the equivalent of over 1000 humans with adding machines.
I might be mistaken, but I seem to recall performing an exercise in a computer science class many years ago using plugboards...