...there was the integrated circuit.
Every semester at the beginning of my MIDI I classes, when discussing the history of electronic music leading up to MIDI, the topic of computer chips comes up. To understand where the, seemingly random, numbers that occur when using MIDI come from, it's important to understand the basic concept of the integrated circuit and the transistor technology that led to it.
I recently found an article online that explains these ideas in a very easy to understand way. I hope you find it useful.