[c-nsp] Parity Errors and Cosmic Rays

[Hank Nussbacher]

On Fri, 6 May 2005, Andre Beck wrote:

Is the equipment that is getting fried in the top of the building or in
the bottom?  I assume you all know the story of the experimental military
radar that was turned on only at certain times and the arc of its range
only hit the top floors of some tall buildings.  If you happened to have
your equipment below floor X - nothing got affected.  Same equipment - 1
flight up - had parity errors.  Swap the equipment and the parity errors
stayed with the top floor equipment.

-Hank

> On Thu, May 05, 2005 at 12:14:21PM -0400, Bill Wichers wrote:
> >
> > I remember reading somewhere once that a neutrino hitting a DRAM cell will
> > release just enough energy to flip the state of one bit...
>
> A *neutrino*? So if the starter of this thread really managed to get
> *multiple* hits of *neutrinos* in his DRAM *chips*, he should probably
> try whether his beeing a unique statistical fluctuation gets him
> anything in a lottery or Vegas ;)
>
> If at all cosmic rays (which smells mostly like a BOFH excuse if not
> founded by some reasoning like high altitude or bad space wheather in
> progress) I'd rather expect alpha to do the damage, or the shower of
> particles created by a high energy particle like a myon.
>
> In practice, slowly decaying hardware is often due to way more primitive
> reasons, mostly bad electrolyte capacitors (which tend to be used in
> power supply components and thus cause supply voltage to be unstable or
> out of the expected range). They age progressively at increased
> temperatures - something very common in insufficiently air conditioned
> IT racks. MTBF reduces drastically with increasing temperature. But
> even under ideal conditions, with the practice of selling incorrectly
> declared capacitors that came about in the last years, almost anyone
> can have this problem.
>
> --
>                   The _S_anta _C_laus _O_peration
>   or "how to turn a complete illusion into a neverending money source"
>
> -> Andre Beck    +++ ABP-RIPE +++    IBH Prof. Dr. Horn GmbH, Dresden <-
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