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Oct 26, 2016 at 19:52 vote accept enigmaticPhysicist
Oct 26, 2016 at 19:49 history edited enigmaticPhysicist CC BY-SA 3.0
write after read isn't necessary.
Oct 26, 2016 at 19:45 comment added enigmaticPhysicist I just remembered these hard drives also use error correction. That's how they can get away with it. Very interesting. And I know about caching, BTW.
Oct 26, 2016 at 8:46 comment added sawdust Here's a patent for the (integrated) disk controller to automatically perform a read-after-write. Look for the paragraph near the end that starts with "There is a performance cost associated with this RVaW feature..." that validates my first comment. I have no idea if any HDD actually uses this scheme.
Oct 26, 2016 at 8:32 comment added sawdust "It seems fairly obvious" -- Only if you're paranoid. You probably don't even know what kind of write caching policy is employed in your HDD. See Write Caching. IOW your OS could be notified that the write operation is successfully complete before the the sector has been actually written, much less verified.
Oct 26, 2016 at 6:01 comment added enigmaticPhysicist Wow, really, it isn't on by default? Crap, I'm going to go figure out how to enable that. It seems fairly obvious.
Oct 25, 2016 at 22:57 comment added sawdust "When a sector is written, it is immediately read back" -- Not true. Such an operation is called "write-then-read" or "write verification", and is not a standard write operation (because such an extended operation requires another revolution of the platter).
Oct 25, 2016 at 22:24 review Close votes
Nov 9, 2016 at 3:04
Oct 25, 2016 at 22:09 answer added DavidPostill timeline score: 2
Oct 25, 2016 at 22:01 history asked enigmaticPhysicist CC BY-SA 3.0