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by nmrm 4069 days ago
> i didn't get whether they were able to show an actual path of how UA could have occurred

I think the answer is no -- there was never a clear demonstration of an extant buggy execution trace. Just a preponderance of evidence that such a trace could exist.
1 comments
tracker1 4069 days ago
The lack of ECC memory means that you don't even need that... the effects of a little solar flare, or even noise from a powerline nearby could have caused the issue.
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trhway 4069 days ago
no. there were multiple reports of UA. Solar flare, etc... can't cause such consistency.
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teamonkey 4068 days ago
Yes, I'm sure it was a bug in this case. However, this paper shows that RAM errors are so common you really don't want non-ECC in anything safety-critical.

http://www.cs.toronto.edu/~bianca/papers/sigmetrics09.pdf

   For example, we observe DRAM error rates that are orders of magnitude higher
   than previously reported, with 25,000 to 70,000 errors per billion
   device hours per Mbit and more than 8% of DIMMs affected
   by errors per year. We provide strong evidence that memory
   errors are dominated by hard errors, rather than soft errors, which
   previous work suspects to be the dominant error mode
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