On Wed, 11 Nov 2009, Tim Cook wrote:
I'm well aware of the fact that SSD mfg's put extra blocks into the
device to increase both performance and MTBF. I'm not sure how that
invalidates what I've said though, or even plays a roll, and you
haven't done a very good job of explaining why you think I'm wrong.
TRIM is simply letting the device know that a block has been deleted
from the OS perspective. In a caching scenario, you aren't deleting
anything, you're continually over-writing. How exactly do you
foresee TRIM being useful when the command wouldn't even be invoked?
The act of over-writing requires erasing. If the cache is going to
expire seldom-used data, it could potentially use TRIM to start
erasing pages while the new data is being retrieved from primary
storage.
Regardless, it seems that smarter FLASH storage device design
eliminates most of the value offered by TRIM.
Bob
--
Bob Friesenhahn
bfrie...@simple.dallas.tx.us, http://www.simplesystems.org/users/bfriesen/
GraphicsMagick Maintainer, http://www.GraphicsMagick.org/
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