> Getting it going with files in a different location is encouraging
>=20
> I guess I don't understand how a different location can have any
> effect, given that the FTL maps that location to some other location
> after every write, or read disturb re-write.

FYI,

the project has now been running continuously for 12 days and
the two files have been read from the card > 1,000,000 times.
Nothing untoward has happened and I'm not noticing any
degradation in quality

My plan is still to read those most-often read files from RAM. If
the RAM data is refreshed from the card even as frequently as
daily that means a very very long theoretical lifetime. Obviously
other factors will (or just could ?) set a practical lifetime but for
now it's enough to know that the files can be read an enormous
number of times

It's possible that the project could refresh every data block on the
card by reading it to RAM and writing it back, perhaps once a year.

There are ~ 500,000 data blocks. I don't know how long it would
take to do them all at once via SPI, although loading the card with
files via USB doesn't take very long, just a couple of minutes. The
project could time-out annually in the middle of the night for as long
as it takes. Or the other option is refreshing blocks when time is
available, as an on-going preventive maintenance process.

Automatically re-writing the card just once a year *shouldn't*
be too stressful or cause out-of-spec wear and tear

Joe



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