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Comment by tyingq | Hacker News Reader

Sun Microsystems had some Sparc servers where the on die cache didn't have ECC. And, cosmic rays created issues: https://docs.oracle.com/cd/E19095-01/sf4810.srvr/816-5053-10...

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In a more dramatic example, Virginia Tech strung together over a thousand PowerMac G5s in a cluster they called the “Big Mac”, and it was one of the fastest (and cheapest) supercomputers of the world at the time. Unfortunately its lack of ECC RAM made its failure rate so high it would have trouble even booting. They dismantled it and sold the machines away one at a time and replaced the entire thing with an Xserve array instead, which had ECC.

I've always wondered whether the orientation of the memory chips in your computer made a difference for cosmic ray errors. That is to say, if their face is to the sky vs. their edge, will it affect the error rate?

Not sure how you would do the math there. Edge up would maybe be a smaller target, but hits would pass through more silicon.

Cosmic rays can come from any angle, and even pass through the entire earth without impacting anything. (millions of them are zipping through you and your RAM, right now! electrons barely dodging out of the way in time.)

I think (but have no reference) that the amount of cosmic rays the planet blocks by being in the way is dwarfed by the effects of the magnetosphere and solar rays.

Watching an alcohool fog chamber is such a cool experience.

Slight nit-pick: Neutrinos are the ones that are zipping through you and the Earth. They interact with things very rarely and have no real charge anyway. The rays you'd worry about with computer hardware are photons (gamma rays) with high energy enough to create new charged particles. Also other charged particles like muons and their decay cascades.

You can try the experiment at home. The equipment is ~$100 : https://hackaday.com/2017/11/27/make-a-cheap-muon-detector-u...

It's also a really good random number generator, for those Hackers/crypto people that would like a true source of randomness.

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