问题
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Cosmic Rays: what is the probability they will affect a program?
Is this just a tongue in cheek expression or is this really true, and if so, what precautions should we take in software (or these precautions hardware only)?
回答1:
Well, I did dig up this paper, which claims that your RAM will get bit alterations from "Atmospheric Neutrons" (aka: Cosmic Rays) at a rate of about 1.3*10^-12 /bit/hour.
An article by Berke Durak uses that to calculate that your probablilty of having at least one bit error in 4 gigabytes of memory at sea level on planet Earth in 72 hours is over 95%. Of course that assumes you are using non-error-correcting memory (non-ECC). With ECC, he figured, you can wait 2.7 million years before you get an uncorrectable bit error at a probability of 96%.
回答2:
Alpha particles, not gamma rays, but yes.
回答3:
Gamma rays from space can't get through the atmosphere -- that's why gamma ray astronomy has to be done using satellites. You're probably thinking of cosmic rays -- high energy charged particles, rather than photons -- and yes, they can cause bit flips and other such effects due to the ionization that can occur when they interact with the atoms in semiconductors.
来源：https://stackoverflow.com/questions/4109218/do-gamma-rays-from-the-sun-really-flip-bits-every-once-in-a-while