On Wed, Mar 18, 2015 at 12:56:50AM +1300, IVP wrote:
> It's most perplexing. I've looked around the web but not yet found
> any mention of reads causing data degradation.  If it doesn't then
> it's hard to explain how the file can be read successfully thousands
> of times and then start giving trouble.

On the other side of the FTL, in the managed flash cells, reads do
cause degradation, but the FTL is supposed to handle that as normal
operation of the firmware, and automatically recharge the cells.

> The seemingly random time to failure after each power-up is also
> odd. You'd think that it would not work instantly rather than at any
> time up to a few minutes.
>=20
> All I can do for the time being is just let it run until it
> fails. After the format/reload the file has been accessed almost
> 20,000 times so perhaps it'll fail again tomorrow.

Since there's an FTL, and the FTL CPU has some non-flash memory, it is
possible for the number of accesses by your firmware to be much
greater than the number of accesses to the flash cells.  It may depend
also on the pattern of access.

> If/when it does I hope I'll learn something useful.

Do let us know.  I agree with another post that reading the card with
a computer operating system may give more detail as to the stored
failure state.

--=20
James Cameron
http://quozl.linux.org.au/
--=20
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