state of support for "external ECC hardware"

Ivan Djelic ivan.djelic at
Thu Nov 8 14:07:14 EST 2012

On Thu, Nov 08, 2012 at 04:32:27PM +0000, Gerlando Falauto wrote:
> Right, datasheets and TNs don't even mention what the threshold actually 
> is. They just say "Rewrite recommended". Perhaps you could get some 
> feeling while running your tests? I mean, if you could get bitflips by 
> using host-software ECC (within a reasonable time), and after enabling 
> on-die ECC you couldn't anymore, it probably means HW ECC won't tell you 
> about bitflips until they reach a number higher than 1. Am I right?
> [Did you ever ask Micron by any chance?]

IIRC, Micron on-die ECC reports a "rewrite recommended" status when the
number of bitflips has reached the internal error correction capability
(4 in my case). In other words, a "rewrite recommended" means you should
rewrite the block ASAP before an additional bitflip triggers an ECC failure.


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