Does it have to be double? I know it's not a direct analogue, but parity schemes like RAID 6 or ECC RAM don't double the cost. So the question is, how do you c

Does it have to be double? I know it's not a direct analogue, but parity schemes like RAID 6 or ECC RAM don't double the cost. So the question is, how do you check these results without actually doing them twice? Is there a role here for frameworks or OS to impose sanity checks? Obviously we already have assertions, but something gentler than a panic, where it says "this is suspect, let's go back and confirm."