Re: [PATCH 00/22 take 3] UBI: Unsorted Block Images

[JÃrn Engel]

On Mon, 26 March 2007 00:46:33 +0100, David Woodhouse wrote:
> On Mon, 2007-03-26 at 00:55 +0200, JÃrn Engel wrote:
> > > although, since you can flip bits to 1 without requireing an erase you 
> > [ vice versa.  you can flip bits to 0 without erasing. ]
> 
> And on NAND flash you can't just do it in multiple cycles one bit at a
> time. The 'tally' trick isn't viable there.

You can on NAND.  ECC is done in software.  And for a data structure as
simple as the 'tally', foregoing ECC is not a huge problem - most
bitflips are easily detected and the remaining only cause off-by-a-few
on the erase count.

On NOR with transparent (hardware) ECC you can't.

JÃrn

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