[yjftsjthsd-h]

To your first couple points: I trust hardware less than you.

> What should it do? Blindly hand you the data without any indication that there's a problem with the underlying block?

Well, that's what it does now, and I think that's a problem.

> Without an fsck what mechanism do you suppose would manage these errors as they're discovered?

Linux can fail a read, and IMHO should do so if it cannot return correct data. (I support the ability to override this and tell it to give you the corrupted data, but certainly not by default.) On ZFS, if a read fails its checksum, the OS will first try to get a valid copy (ex. from a mirror or if you've set copies=2), and then if the error can't be recovered then the file read fails and the system reports/records the failure, at which point the user should probably go do a full scrub (which for our purposes should probably count as fsck) and restore the affected file(s) from backup. (Or possibly go buy a new hard drive, depending on the extent of the problem.) I would consider that ideal.