>>>>> "tt" == Toby Thain <t...@telegraphics.com.au> writes:
c> For writing, application-level checksums do NOT work at all,
c> because you would write corrupt data to the disk, and notice
c> only later when you read it back
tt> Right, it would have to be combined with an always read-back
tt> policy in the application...?
aside from being wasteful, that won't work because of ``cached
goodness''. :)
It's allegedly common for programs to read what they've just written
during normal operation, so various caches usually consider whatever's
written as ``recently used'' for purposes of expiring it from the read
cache. If corruption happens below a cache (ex. in the NFS client),
as it probably will, you won't detect it by read-after-write.
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