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From: Charles Manning <manningc2@actrix.gen.nz>
To: "Artem B. Bityutskiy" <dedekind@yandex.ru>
Date: Mon, 12 Dec 2005 06:53:33 +1300
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Cc: Linux MTD <linux-mtd@lists.infradead.org>
Subject: Re: NAND simulator
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On Monday 12 December 2005 02:46, Artem B. Bityutskiy wrote:
> Charles Manning wrote:
> > Yes please.
>
> Uhh, will pospone this for now, will try to repair JFFS2 which doesn't
> work after the last month's commits. Crud! Not sure whom to blame so far.
>
> > Can nandsim simulate storage larger than physical RAM (just swapping out)
> > or would this need special support (eg. add some block device support?
> > We're getting people in YAFFSland who are working with 8Gbytes of flash
> > (and it will only get bigger!) and I expect you'd want large emulations
> > to stress JFFS3. Being able to simulate areas up to, say, 16Gbytes for
> > now would be a nice thing.
>
> Well, did not plan it. But we probably may add this functionality. We
> may borrow it from mtd2blk ...
>
> > A way of simulating a failure (bit flip, write error) would also be handy
> > for testing fs and ecc error handling.
>
> Yeah, good feature. But I'm not sure how to implement an interface for
> this. It is probably easier to hack nandsim and add this manually...

Manual hacking does work. I have done stuff like that in the past. Perhaps 
dynamic hacking could be done via procfs? 
eg, perhaps somethiong like
echo "flip 12345 400 1" > /procfs/nandsim   # flip bit 1 in byte 400, page 
12345