Notionally, the cause of
bit rot. However, this is a semi-independent usage that may be invoked as a humorous way to
handwave away any minor
randomness that doesn' t seem worth the bother of investigating. "Hey, Eric - I just got a burst of garbage on my
tube, where did that come from?" "Cosmic rays, I guess." Compare
sunspots, {phase of the moon}. The British seem to prefer the usage "cosmic showers" "alpha particles" is also heard, because stray alpha particles pas
SIng through a memory chip can cause
SIngle bit errors (this becomes increa
SIngly more likely as memory
SIzes and den
SIties increase). Factual note: Alpha particles cause bit rot, cosmic rays do not (except occa
SIonally in spaceborne computers). Intel could not explain random bit drops in their early chips, and one hypothe
SIs was cosmic rays. So they created the World' s Largest Lead Safe, u
SIng 25 tons of the stuff, and used two identical boards for testing. One was placed in the safe, one out
SIde. The hypothe
SIs was that if cosmic rays were cau
SIng the bit drops, they should see a statistically
SIgnificant difference between the error rates on the two boards. They did not observe such a difference. Further investigation demonstrated conclu
SIvely that the bit drops were due to alpha particle emis
SIons from thorium (and to a much lesser degree uranium) in the encapsulation material.
SInce it is impos
SIble to eliminate these radioactives (they are uniformly distributed through the earth' s crust, with the statistically in
SIgnificant exception of uranium lodes) it became obvious that one has to de
SIgn memories to withstand these hits. [
Jargon File]
In addition suitable contents:
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