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Build Your Own Apollo Guidance Computer
PingXao writes "Well, if you can't exactly give the Moon you can give the gift of a computer to get you there. Almost a year ago this Slashdot story about the Apollo 11 Guidance Computer referenced a pretty cool Dr. Dobbs Journal article from their History of Computing series. Now there's this guy who built one in his basement! It took him 4 years, $2,980 in cash, 2,500 hours of labor and 15,000 hand-wrapped wire connections with 3,500 feet of wire to build. It might be next Christmas before you could build one of your own to give as a gift, but he promises you can build your own for less and it will be better than his. The perfect gift for the space geek who has everything. This guy is my hero."
I understand that it took him a long time and it's quite an incredible feat, but how is it usable/testable? Apollogize for my stupidity.
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An emulator already exists. It has been released as free software under the GPL. It supports Linux and Windows.
People can (and have) ported just about anything to anything. There's a version of X11 that runs entirely under Java. There are patches to make Linux run on a VAX. Hell, ply Linus, Alan Cox and Richard Stallman with enough beers, I'd be willing to bet you could talk them into developing the necessary hooks in Linux, GCC and binutils to run Linux on a Z80, a 6502, or (in this case) a lunar module.
You'd have to assume sufficient physical storage of one sort or another, in order to run the kernel, but provided that was done, I can't see any objection.
(I actually wish someone WOULD port Linux to one of the ancient architectures, as it would provide an actual demonstration of Alan Turing's computability theory. At present, it's just words. People don't work too well with words, they work much better with examples they can see, experiment with, and learn from.)
It's a small world and it smells funny; I'd buy another if it wasn't for the money; Take back what I paid (SoM)
well, you could do it without computers, would just be even harder, plus astronauts would have one sucky time flying the craft by hand to the moon. But it could be done, there is always a way without a computer.
Actually, there is not always a way without a computer. Some modern fighter jets are inherently unstable (in order to provide faster response) and no human being in the world could react quick enough to keep those planes from wadding themselves into little silver balls. Their computers make multiple control surface adjustments per second.
As I recall, they use some rather antiquated computers aboard the shuttles for this very purpose.
As I understand it, it's easier to radiation harden a 386 or 486 processor than a Pentium or higher CPU. (Although I read recently that might be changing with a new CPU design but I forget which one.) I heard that the shuttle still has a few 8086 (or is that an 8088) computers on board.
Trivial note: You often see 8086/8088, 80286 and higher CPUs, but have you ever seen an 80186 CPU? IBM used to make an ISA network card (Token Ring?) that used the 80186 as the processor.
Yes, we are certainly capable of sending small probes out to discover facts about the solar system, but those facts will remain useless until we can get there in person.
I remember reading a statement somewhere regarding rocket tech, along the lines of 'a 5% increase in current booster efficiency would allow double the payload'. Anyone know these numbers?
"A language that doesn't affect the way you think about programming, is not worth knowing" - Alan Perlis
The Saturn V itself had quite a lot of processing power for the day. The LEM and CM/SM were fully controllable. The basic programs were in ROM but they could be used quite flexibly. On Apollo 13, I seem to remember that they had to use the computer for the pre-reentry manouvers.
In your example of the B2, I agree. The flying wing was considered extremely difficult to manouver. Now the B2 along with many modern warplanes use instability to increase manouverability, but the control is eased through the use of processing power.
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