[Ma-linux] Testing RAM with MemTest86+

[Alexey Toptygin]

On Tue, 6 Jul 2010, Igor Birman wrote:

> I thought the solar flare comment was meant as a cosmic ray comment, 
> though from what I understand, cosmic rays come from exploding stars, 
> while radiation from solar flares is largely deflected by our 
> magnetosphere, and helps to sweep away the cosmic rays.  I believe it is 
> perfectly possible for a cosmic ray to flip a bit on a RAM chip..

Radiation from solar flares is mostly deflected by the magnetosphere, but 
the magnetosphere gets heated as a reult and gets less transparent for 
radio waves (thus it can disrupt communications with sattelites or 
communications that bounce radio waves off the upper atmosphere). It does 
not have a significant impact on the rate of cosmic rays hitting the earth 
because it's not dense enough.

High energy cosmic rays can easily flip a bit in a memory chip (in fact 
one type of detector that can be used to measure the charge of cosmic rays 
is similar to a memory cell with a very large surface area), but they like 
to interact with everything; most of them don't get very far in the 
atmosphere, so cosmic ray telescopes all have to be launched into space or 
at least lofted above 99% of the air on a helium balloon. If you have a 
concrete roof over your head only a tiny fraction of cosmic ray particles 
will make it through. If you have another floor or two above you, you can 
forget about cosmic rays.

 			Alexey