@casascius: RAID with any kind of redundancy (i.e, not RAID-0 or JBOD) *does* compare reads and notify of an error and/or fill in the gaps if possible.

If this were a software error, you'd see errors a lot more often than 1-in-a-trillion+.

@iamzill: why would Philip K. Dick's estate sue you? that's exactly how high-reliability systems have worked since the invention of the computer.