3 ms·
Having worked on system where we had a crc on almost all data structures, let me tell you that bit flips happen more often then you want to know. Not everyone
by com2kid 9y ago
Having worked on system where we had a crc on almost all data structures, let me tell you that bit flips happen more often then you want to know.
Not everyone crcs 100% of their structs.
If they don't, data is being slowly corrupted.
- jjeaff 9y agoHow do you know they were bit flips? And if they were, how do you know they were soft errors that could have been corrected with ecc and not hard errors that would have happened either way?
- com2kid 9y agoBecause we had insanely good crash reporting and we root caused every crash report we got in that had more than half a dozen hits in the wild. Hardware was at fault. Turns out suppliers push the truth a bit here and there about their chips, what is supposed to be an identical part # isn't always identical, parts from different manufacturers that are supposed to be interchangeable aren't, and technical manuals aren't always the best. We had (what we thought was) rigorous memory testing in place at the factory, but under certain extreme conditions there was a 100% reproducible flip of a few bits in RAM. It was almost always the same bits, thankfully, that made it possible to track down!