5 ms·

Electron will still use too much RAM though... /s This is cool. It makes me wonder how big a computer can be. If bounded by the speed of light, could a planet-

by jrq 8y ago

Electron will still use too much RAM though... /s This is cool. It makes me wonder how big a computer can be. If bounded by the speed of light, could a planet-sized computer ever make any sense?

overcast 8y ago
No, because even at the speed of light, a trip around the earth is 133ms. That's also a straight line, and in a vacuum. Much slower when it involves an atmosphere, optical fiber, and different routes.
- jrq 8y ago
  That's not so long though, in the scheme of things. Especially if the computer was very fast. I read this book Artemis by Andy Weir recently (the guy who wrote the Martian) and it mentioned a moon Internet, and it was like 8 seconds away from the earth Internet or something like that. However, and the book didn't mention it, but what if a computer could be constructed that could perform extremely large calculations, and it was cheaper to produce there? In the book, they used a lot of glass for decor, because the ingredients to manufacture it were byproducts of other manufacturing already present, but something like that could be possible in space. I like to imagine a satellite orbiting earth, with a little factory onboard, and it would send out probes and repurpose all the space junk in orbit and convert it to energy or use it to build stuff. A planet computer could be expanding itself in that same way, and even though the calculations' results might be delayed, that might be more effective. If humans make it another couple hundred years, they're gonna get to start thinking and building that stuff. That'll be cool
  - lodi 8y ago
    Actually the moon is only 1.3 light seconds away, so a ping of ~2.7s to the moon is possible! Mars would be annoying to communicate with though: 25-44.8 minutes for a roundtrip signal.
- dahart 8y ago
  >> If bounded by the speed of light, could a planet-sized computer ever make any sense? > No, because even at the speed of light, a trip around the earth is 133ms. Sure you could. End-to-end latency isn't necessarily a deal breaker. There would be big design problems for sure, but there are already CPUs that have nearby circuits running at higher rates than further away circuits, with async communication in between. And there have been clock-skew tolerant designs for decades to get around speed of light problems even at ~1cm distances. It's common to use the H-tree to ensure that all clock paths are the same length from the clock source, in other words the latency is factored out by making it uniform across the die. Some references & examples: https://en.wikipedia.org/wiki/H_tree https://en.wikipedia.org/wiki/H_tree http://users.ece.utexas.edu/~mcdermot/vlsi-2/Lecture_8.pdf http://users.ece.utexas.edu/~mcdermot/vlsi-2/Lecture_8.pdf https://web.stanford.edu/class/archive/ee/ee371/ee371.1066/lectures/Old/lect_08_2up.pdf https://web.stanford.edu/class/archive/ee/ee371/ee371.1066/l...
- sigi45 8y ago
  Make it like a brain and it is not a problem. It is also necessary to build it like a brain because otherwise you have a memory bandwith limit too high. Instead of having RAM and a CPU, you would have a neuro network like structure using light. Than the latency is not relevant because it would optimize around it.
CyberDildonics 8y ago
There would be a lot of latency between components. They would have to be hooked up with some sort of world wide network, some sort of inter-planet-net
smaddox 8y ago
Yes, but it would be blown up right before it finished computing the question to the ultimate answer.

by jrq 8y ago

Electron will still use too much RAM though... /s This is cool. It makes me wonder how big a computer can be. If bounded by the speed of light, could a planet-sized computer ever make any sense?

overcast 8y ago

No, because even at the speed of light, a trip around the earth is 133ms. That's also a straight line, and in a vacuum. Much slower when it involves an atmosphere, optical fiber, and different routes.

jrq 8y ago
That's not so long though, in the scheme of things. Especially if the computer was very fast. I read this book Artemis by Andy Weir recently (the guy who wrote the Martian) and it mentioned a moon Internet, and it was like 8 seconds away from the earth Internet or something like that. However, and the book didn't mention it, but what if a computer could be constructed that could perform extremely large calculations, and it was cheaper to produce there? In the book, they used a lot of glass for decor, because the ingredients to manufacture it were byproducts of other manufacturing already present, but something like that could be possible in space. I like to imagine a satellite orbiting earth, with a little factory onboard, and it would send out probes and repurpose all the space junk in orbit and convert it to energy or use it to build stuff. A planet computer could be expanding itself in that same way, and even though the calculations' results might be delayed, that might be more effective. If humans make it another couple hundred years, they're gonna get to start thinking and building that stuff. That'll be cool
- lodi 8y ago
  Actually the moon is only 1.3 light seconds away, so a ping of ~2.7s to the moon is possible! Mars would be annoying to communicate with though: 25-44.8 minutes for a roundtrip signal.
dahart 8y ago
>> If bounded by the speed of light, could a planet-sized computer ever make any sense? > No, because even at the speed of light, a trip around the earth is 133ms. Sure you could. End-to-end latency isn't necessarily a deal breaker. There would be big design problems for sure, but there are already CPUs that have nearby circuits running at higher rates than further away circuits, with async communication in between. And there have been clock-skew tolerant designs for decades to get around speed of light problems even at ~1cm distances. It's common to use the H-tree to ensure that all clock paths are the same length from the clock source, in other words the latency is factored out by making it uniform across the die. Some references & examples: https://en.wikipedia.org/wiki/H_tree https://en.wikipedia.org/wiki/H_tree http://users.ece.utexas.edu/~mcdermot/vlsi-2/Lecture_8.pdf http://users.ece.utexas.edu/~mcdermot/vlsi-2/Lecture_8.pdf https://web.stanford.edu/class/archive/ee/ee371/ee371.1066/lectures/Old/lect_08_2up.pdf https://web.stanford.edu/class/archive/ee/ee371/ee371.1066/l...
sigi45 8y ago
Make it like a brain and it is not a problem. It is also necessary to build it like a brain because otherwise you have a memory bandwith limit too high. Instead of having RAM and a CPU, you would have a neuro network like structure using light. Than the latency is not relevant because it would optimize around it.

CyberDildonics 8y ago

There would be a lot of latency between components. They would have to be hooked up with some sort of world wide network, some sort of inter-planet-net

smaddox 8y ago

Yes, but it would be blown up right before it finished computing the question to the ultimate answer.