On Mon, 9 Feb 2009, marek.zukal wrote:
> The thing is that I need no huge space for data. Just a few MB but
> definitely more than any battery backed ram module from TS provides,
> so the flash is the best way.
That's good. Re-using just a small percentage of a large flash card, allows
the wear leveling to cycle thru' a higher percentage of free blocks, and so
means the flash lasts longer.
One of the worse situations is to have a card 95% full with static data,
and you are rewriting data in the remaining 5%. The wear levelling can only
cycle round the small percentage of free blocks, so they wear out quicker.
> I am most worried about the superblock
> of the file system because this is where the most of the stress will
> be since the files are just small logs. And I have not seen any
> description of any card that would say "The wear balancing on this
> card is done by physical block rotation, remapping etc." so it would
> benefit from the fact that most of the card is actually unused. I
> found a lot of papers about flash wear balancing but everything was
> very general. I know that these cards are consumer electronics in the
> first place but I would expect the manufacturers to be more embedded
> friendly.
>
>
>
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