Computers don’t have to be Electronic

I make my living, and have for 25 years, as a computer engineer. Frankly, I never post about that here because it’s boring. I’m not going to say we’ve solved every problem in computation, but it is a fairly mature field at this point, so unless I wanted to explain how it worked from scratch, there’s no point. And I have nothing to add to that conversation – many far more patient than I have done so on YouTube and other media.

But there is an interesting aspect to computing I bet you’d never considered.

Modern computing is made up of some fairly well understood principles. You’ve got logic gates, which take a signal or signals in and manipulate them in a predefined way. Those are built up into some more complicated structures. Stick a few hundred thousand of them together. And you can have a rudimentary processor. Stick them together in a different configuration, and you get memory. All of the internal workings of a computer – and I don’t care which one – are based upon signal processing. The signals are binary for convenience but they don’t have to be – some of the first computers were decimal based.

Electronics are a rather convenient medium for these signals. You can make very fast electronic switches that are extremely tiny and operate on very small amounts of current. But these signals can be anything. They can be mechanical, optical or something we haven’t thought of yet. You can even simulate them inside a computer itself. Point being, that the actual medium in which a computer is built is divorced from the actual computation itself.

Bet you’d never thought of that.

This has some interesting real world consequences. One of those consequences is that the primary issue that most hardware designers and technicians have to solve are physical ones – good software rarely fails on its own (bad software always does). You’ve got bad solder joints or traces, mechanical stress or failure, tin whiskers causing failure of microchips, and even the stray cosmic ray randomly flipping bits in memory. Generally when something usually reliable fails, it’s a physical hardware issue. Those kinds of things can be easily repaired unless a chip itself fails. Then you just gotta replace the chip.

Computers are modern miracles, but the electronics are only one part of the miracle. The rest of the miracle is the theory of computation that makes it possible. You could have a mechanical computer that does everything your phone does now. Of course it’d be slow and the size of Texas, but the point is, it’s possible. Think of that next time you plug your phone into a charger.

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