It took me forever to figure out that these strange thingies were physical systems in the computers themselves, and a bit longer to realize that they didn’t look anything like what I thought they did. (I still haven’t bothered to look it up, despite having a non-negligible desire to know.)
I think my computer engineering degree makes me qualified to explain the physical workings of a computer. I’m a bit too sleepy right now to write up a detailed explanation, but I’ll give it a try later if you ask.
Anyway, a much better metaphor for a computer program is a list of directions, like the directions that you find in the box when you buy furniture that you have to put together yourself. They could be really complicated directions, but they’re still just directions, sitting there doing nothing until something reads them and follows them. Obviously most computers don’t read programs that are written on paper, and I don’t know how all the different storage media work, but whenever a computer actually executes a program, that program is “written down” somewhere.
On the other hand, the steampunk-like assembly of gears you’re envisioning actually is a reasonable metaphor for a CPU. And you really can build a computer out of that sort of thing; Charles Babbage actually designed a fully programmable mechanical computer in 1837, but it was never built. Today’s computers are made out of microscopic devices that manipulate electricity instead of things that move chunks of wood and metal around, but it’s still not a bad metaphor—it doesn’t matter what you build your NAND gates out of, just that they’re all connected properly.
I think my computer engineering degree makes me qualified to explain the physical workings of a computer. I’m a bit too sleepy right now to write up a detailed explanation, but I’ll give it a try later if you ask.
Anyway, a much better metaphor for a computer program is a list of directions, like the directions that you find in the box when you buy furniture that you have to put together yourself. They could be really complicated directions, but they’re still just directions, sitting there doing nothing until something reads them and follows them. Obviously most computers don’t read programs that are written on paper, and I don’t know how all the different storage media work, but whenever a computer actually executes a program, that program is “written down” somewhere.
On the other hand, the steampunk-like assembly of gears you’re envisioning actually is a reasonable metaphor for a CPU. And you really can build a computer out of that sort of thing; Charles Babbage actually designed a fully programmable mechanical computer in 1837, but it was never built. Today’s computers are made out of microscopic devices that manipulate electricity instead of things that move chunks of wood and metal around, but it’s still not a bad metaphor—it doesn’t matter what you build your NAND gates out of, just that they’re all connected properly.
The British Science Museum built his #2 engine about 20 years ago. No, never built when it was relevant :P
Yes, but the design that they built wasn’t one of his designs for a general purpose computer.