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Re: Generalized Flash question



On Mon, 27 Nov 2000, John van V. wrote:
> Somebody told me a week ago that flash only works well if you write to it very
> infrequently because it, well breaks.
> 
> Is this true?? I never heard this before... in the process of testing JFFS, I
> imagine you give it quite a workout.

It breaks after X erase-cycles, where X is usually a very large number
today (I don't have any datasheets here, but I'd guess X > 100,000). So as
long as you don't rewrite the same bit all the time, but spread your
writes over the available flash area, you'll be quite safe. Although, it
would not be recommended to run a /tmp or /var/spool directory on a flash
filesystem I guess. 

JFFS does rudimentary wear-levelling because of the log-structured design,
we write new data at the end of the circular log instead of rewriting the
block where the old data was. More advanced algorithms will come
eventually..

-Bjorn
 


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