On Wednesday 03 March 2010 23:33:31 Sven Van Asbroeck wrote:
> Hello Shivdas,
>
> > So, what does actually "check pointing" saves while
> > unmount?
>
> It's my understanding that the check point consists of the RAM data
> structure which is assembled when a yaffs partition is scanned. It consists
> of meta-information associated with each chunk and block. If you'd like to
> know more, I recommend reading the 'How Yaffs works' document, which is
> available in CVS.

A full scan builds up a set of data structures that define the file system 
state. A checkpoint captures a reduced version of that, enough to 
reconstitute the main part of the state and the rest can be built up on a 
lazy basis.

>
> > and Is it
> > safe to use check-pointing always in final product?
>
> According to Charles, checkpointing is designed to be used in the way you
> describe. To my knowledge, no open checkpointing issues exist, but you
> should search the archives. If you are concerned about the checkpoint
> diverging from the meta-information on flash, you could a) disable
> checkpointing altogether, or b) submit a patch implementing a checkpoint
> counter ;-)

You can also choose to mount ignoring checkpointing with

mount -t yaffs2 -o"no-checkpoint-read" ...

-- Charles