[Beowulf] Re: ECC Memory and Job Failures (Huw Lynes)

Vincent Diepeveen diep at xs4all.nl
Mon Apr 27 10:30:52 EDT 2009




On Apr 24, 2009, at 4:20 AM, Robert G. Brown wrote:

> On Thu, 23 Apr 2009, John Hearns wrote:
>
>> Cosmic rays pass through us all the time - I don't know offhand the
>> cosmic ray flux.
>> Like Joe I did the cosmic muon lifetime experiment at University.
>> I always wanted to do an undergraduate project using CMOS RAM as a
>> radiation detector - read and write bit patterns to it, and see if  
>> the
>> results match.
>
> Funny, I did it too.  One of my favorite undergrad experiments, proves
> relativity theory, and there is the always muon catalyzed fusion to  
> muse
> over as well.
>
> I don't think memory is all that unstable, especially down where I  
> live.
> In Denver, maybe.  I think you need a lot of RAM, for a long time, to
> see a lot of radiation induced errors, or a source of high energy
> particles.
>

Yeah usually it is a hardware or software bug.

However i noticed that if i saved my tapes (Ultrium2-200GB  
uncompressed, 400GB according to the salesman) at
about 1 meter above the ground here, things go fine. Yet if i save  
them at 2nd floor here that is more risky.
There is definitely more bitflips there. Now that is a lot closer to  
the 2 x 450 MVA powerlines, which are on average at a height of about  
19 meters above ground,
a bit less when a lot of power is on 'em, as the cables tend to get  
very hot then.

Now on paper these powerlines are supposed to not radiate the  
ionising radiation very far. Say half a meter max (which doesn't
really matter for life & death, as at 2 meters distance you're  
already dead in this wet climate).

Would this measurement prove that ionising particles, which cause of  
course cancer, sometimes travel further away from
these cables?

Thanks,
Vincent

>    rgb
>
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>
> Robert G. Brown	                       http://www.phy.duke.edu/~rgb/
> Duke University Dept. of Physics, Box 90305
> Durham, N.C. 27708-0305
> Phone: 1-919-660-2567  Fax: 919-660-2525     email:rgb at phy.duke.edu
>
>
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