Q: Cramfs Vs. Ubifs

Nathan Lynch ntl at pobox.com
Thu Jun 14 02:23:01 EDT 2012

On Thu, 2012-06-14 at 08:37 +0300, Ran Shalit wrote:
> >> I wonder why I didn't find any information about disadvantage of using
> >> ubifs as root file system in embedded system in terms of access to
> >> flash during application life.
> >>
> >
> > This isn't an issue specific to UBIFS.  Look into mlock/mlockall if your
> > application needs to avoid latencies associated with demand-paging from
> > flash or any other storage.
> >
> Can you please elaborate why accessing the flash while main "real-time
> application" is running it is not a problem. I also read in
> free-electrons tutorial on embedded linux such recommendation for
> using file system such as cramfs, ubifs, which also access the flash
> during execution.
> Why is it not a problem for embedded linux ? From my experience with
> other embedded OS, it is not recommended to access flash during
> execution.

Did you read the man page for mlockall?  It does seem to address your
concern as I understand it.

(This has become off-topic for the MTD list IMO.)

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