From: Robin Lee Powell (rlpowell@digitalkingdom.org)
Date: Tue Oct 13 2009 - 12:20:28 MDT
On Tue, Oct 13, 2009 at 11:08:25AM -0700, Charles Hixson wrote:
> Or if the data is occasionally altered by some external factor.
> E.g., if your memory isn't perfect, and occasionally does
> bit-flips (possibly due to quantum processes).
Silly anecdote time.
I dunno from quantum, but cosmic rays actually *do* cause bit flips
fairly regularily in real life:
http://www.ida.liu.se/~abdmo/SNDFT/docs/ram-soft.html
Sun Support, for a long time, had just the wrong form factor of
cache RAM on its CPUs for this sort of thing; very dense, very
physically large (inches on a side). Support actually told me that
they had a cosmic ray database; a certain kind of crash/reboot was
almost always caused by cosmic rays, but people couldn't just go
back to their boss and say "Enh, cosmic rays", so they had a
database; the first time it happened, they'd enter the CPU in, and
if it happened again, they'd replace it.
-Robin
-- They say: "The first AIs will be built by the military as weapons." And I'm thinking: "Does it even occur to you to try for something other than the default outcome?" See http://shrunklink.com/cdiz http://www.digitalkingdom.org/~rlpowell/ *** http://www.lojban.org/
This archive was generated by hypermail 2.1.5 : Wed Jul 17 2013 - 04:01:04 MDT