Messages in this thread |  | | | Date | Wed, 07 May 2008 14:31:43 +0200 | | From | Helge Hafting <> | | Subject | Re: Compact Flash Question |
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Tomasz Chmielewski wrote: > > How does it work, then? > How can it do wear levelling over the whole CF if some (or most) area > of CF is already used by our precious data/metadata? > It would have to know the areas where no data is stored, but it > contradicts the CF <-> filesystem separation. It don't necessarily need to know. It can swap two used blocks, one often-used and one rarely-used. That way the rarely-used block is rewriten over the previously busy block, and the busy block is moved to the rarely used area that isn't worn. This implies an extra write whenever a busy block is moved. Don't know if anybody do this, but the technique is simple enough.
CF-filesystem separation is necessary, for they can't know in advance what filesystem or partitioning scheme will be used. (I have ext3 on CF, for example...)
Helge Hafting
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