Quote from: bitrick on September 21, 2011, 01:45:18 AM

Quote from: casascius on September 21, 2011, 01:01:49 AM

If this were a hardware error, even a 1-in-a-trillion one, I would expect his machine to be unstable, locking up constantly, his file system growing errors on its own and constantly needing to be fsck'd/repaired/etc. Software errors can be responsible of errors that occur with literally any magnitude of frequency, from one in a zillion all the way to constantly.

I think the experience of myself and maaku differs from yours. I had a similar belief during my first 15 years of working in the computer industry. I did a lot of things with a lot of data and never encountered an obvious internal bit error.

However, in the last ten years I have worked more closely with hardware and I've seen enough errors to believe that hardware is a perfectly reasonable possible source of error in this case. The recent DEFCON paper on bitsquatting awakened a lot of people to the potential for hardware bit errors. Bandwidth of various transmission types, external and internal, and storage capacity has increased so dramatically, that bit errors are popping up in places that previously were so rare as to be ignorable.

I have personally diagnosed a repeatable bit error which flipped a particular bit of the destination address of a DMA transfer on a PCI bus. It only occurred once every several hours on a heavily loaded network device. It caused one connection to be dropped and there were no other obvious ill effects.

Error correction technology is a slam dunk solution for these types of problems, but it has not yet been applied to all the systems that need it.

Here's the paper this man is referring to: http://good.net/dl/k4r3lj/DEFCON19/DEFCON-19-Dinaburg-Bit-Squatting.pdf

As a geek I thoroughly endorse this conversation.