In message <[email protected]>, Joel Jaeggli writes:

The answer is "it depends on so many factors that you do not and
often cannot know, that you might as well give up predicting it at all."

Unless you can get statistics out of the flash-adaptation layer in the
card, there is no way to project what kind of state the flash array
truely it is in.

By the time you get the first bit of relevant information, in the
shape of a read or write error, it is already time to throw the
card out.

If you use the card like it was intended, few writes of big files
(photos in a camera) you will generally be fine.  If you do a lot
of small writes you will generally not be.

For 'big', 'small', 'few' and 'a lot', insert any random numbers
you care to dream up, nobody knows the real numbers.  (A few of
the high end manufacturers have data that is indicative, but they
will only share them under NDA.)

NanoBSD and Fifolog (both in FreeBSD) were both written to specifically
avoid and when unavoidable, to optimize the write pattern for CF card
longevity.

Poul-Henning

-- 
Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
[email protected]         | TCP/IP since RFC 956
FreeBSD committer       | BSD since 4.3-tahoe    
Never attribute to malice what can adequately be explained by incompetence.
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