Axis log based flash filesystem ported to 2.3 and MTD

[Bjorn Wesen]

On Mon, 27 Mar 2000, Scott Anderson wrote:
> Thanks to Alexander, I may not have to.  I'm under the impression that Axis'
> file system implements wear-leveling, so if there isn't an FTL, then the
> file system itself must rotate through free blocks to prevent a given sector
> from being worn out.  Is this correct?  If not, would you mind educating me?

The flash is not divided into blocks in our JFFS. The flash is logically a
single circular append-only file (but with random access of course).
Wear-leveling comes implicitely in that model, since the log-file is
circular.

The only way the flash's sector-coarseness comes into view, is when areas
not in use anymore need to be reclaimed - the garbage collector can only
reclaim if an entire sector is unused (or contains redundant information).

We're in the process of writing a white-paper about this. The concept is
extremely simple; the implementation is not always as simple :) 

-Bjorn



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