Solar Flux (was: Re: China prefix hijack)

Valdis.Kletnieks at vt.edu Valdis.Kletnieks at vt.edu
Sun Apr 11 11:36:05 CDT 2010


On Sun, 11 Apr 2010 16:58:40 BST, Michael Dillon said:

> Would a Faraday cage be sufficient to protect against cosmic ray bit-flipping
> and how could you retrofit a Faraday cage onto a rack or two of gear?

Scientists build neutrino detectors in mines 8,000 feet underground because
that much rock provides *partial* shielding against cosmic rays causing
spurious detection events.

Fortunately, the sun emits almost no cosmic rays.

It does however spew a lot of less energetic particles that will cause
single-bit upsets in electronic gear. Time to double-check that all your
gear has ECC ram - the problem with the UltraSparc CPUs last time was that
they had some cache chips built by IBM.  IBM said "Use these chips in an
ECC config", but Sun didn't.  The ions hit, and the resulting bit-flips
crashed the machines.  Incidentally, Sun sued IBM over that, and the judge
basically said "Well, IBM *told* you not to do that up front. Suit dismissed".

One of the other big issues will be noise on satellite and microwave links
screwing your S/N ratio.

The one that scares me? Inducted currents on long runs of copper. You get a
200-300 mile 765Kva transmission line, and a solar flare hits, the Earth's
magnetic field gets dented, so the field lines move relative to the stationary
copper cable, and suddenly you have several thousand extra amps popping out one
end of that cable. Ka-blam.  The big danger there is that many substations are
not designed for that - so it would basically *permanently* destroy that
substation and they'd get to replace it. And of course, that's a several-weeks
repair even if it's the only one - and in that sort of case, there will be
*dozens* of step-down transformers blown up the same afternoon.

How long can you run on diesel? ;)

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