Ok, if today an excellent batch of experts were stranded on a deserted island, but had bunches of Radio Shack surplus parts, everything except electricity, how good of a computer could they build?
I presume it could not be digital? What could the functions be of the computer? What could it do, I mean?
It could certainly be digital as opposed to analog, in the sense of using discrete as opposed to continuous information values. It just couldn’t be electronic…
This was probably the most sophisticated mechanical computer ever made: Difference engine - Wikipedia
You’re not going to make it with coconuts, though.
How many experts, and in what? If they’re all hardware engineers, I gotta think they’re not gonna come up with much - that’s a pretty specialized field. But if you get some blacksmiths, some mechanical engineers and so on, you could at least make something on the order of Babbage’s analytical engine.
I don’t think Radio Shack parts are gonna do much good, though - if you’re building a mechanical computer, you need mechanical parts, not electronic ones. A waterwheel and coal-fired machine shop would stand you in much better stead.
ETA: to clear up my and **beowulff’s **posts, the difference engine was Babbage’s first computer-like work, but was more of a calculator. The analytical engine was more general purpose, and could be programmed. Either way, I have to think that a more complicated device would be possible, in the absence of electricity, but with it, there’s not much point.
Of course if you had the right parts you could make a waterwheel or some other type of turbine to create electricity.
The Tinkertoy computer could play Tic-Tac-Toe. (It lacked the voice synthesis module to say, “Strange game.”)
Are you asking about building a mechanical, non-electrical computer, or are you asking how good an electronic computer can be built without ever testing it?
Don’t need Radio Shack parts.
The first – it would be a much more suitable question.
I am still uncertain as to WHAT these analog computers do, such as the difference engine. What could it do? Mathematical equations?
Any digital computer is essentially doing nothing but math. You see a picture on your screen, but the computer had to crunch a ton of numbers to tell each pixel what color to be. So… 2+2 = 4 = red.
If you can do basic logic functions, you can get a computer to do anything. The only limits are processing time and memory capacity.
As far as I know the simplest analog computer is a slide rule. The simplest digital computer is an abacus. When I took computer solutions of differential equations as a lab course back in the seventies we actually went over and tried out an old analog computer they had in the chemical engineering department. You could actually wire up components to simulate differential equations and see the solution on an oscilloscope. There was actually some very sophisticated analog computers build for bomb sights and gunnery computers.
http://en.wikipedia.org/wiki/Analog_computers#Electronic_analog_computers
Not really!
Why hasn’t anyone provided a link to this cool cartoon yet?: xkcd: A Bunch of Rocks
Not having a computer in the first place to help I don’t think you would consider anything a person can design unaided to be a good computer. You can build logic machines that work without electricity, but there is no way a person will design and build unaided what we consider even a basic home computer. We have come to far for that.
Because you didn’t read the whole thread before posting.
[sub]just like me.[/sub]
Normally, it bothers me, too when somebody posts in a thread without reading it first (in fact, there’s a thread going about this right now). But people who post links without explaining what they are just have to realize there’s a sizeable group of Dopers that will not click on the link.