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Re: Anyone using mtd on NAND flash?



On Wed, 13 Sep 2000, David Woodhouse wrote:
> Definitely. With RW compression, this gets even more complicated. If you
> have a node covering a certain range of a file, but a subsequent write has
> changed some of the data, then it's entirely feasible that when you come to
> GC the first node, the data no longer compress as well. 

I would actually follow Linus and the iPaq guys suggestions and not
support RW compression at all (at least not unconditionally or in the
beginning). In most embedded products it makes more sense to concentrate
the compression to the stuff that does not change very much, and that is
usually the kernel image and program binaries, libraries etc, stuff that
can be one-time compressed at the vendor.

RW compression could be added as a user-mode tool, "jffs_compress
<filename>" which checks for free space and collects the entire file,
compresses it, and writes it back, without the problems you write. If it
does not fit without GC, the operation is cancelled.

-Bjorn