Ubi2- using NandSim for simulating flash and mounting ubi.

[Shweta Shetty]

Hi ,
Thank you for your help.
We had not tried the "ubinize" utility and hence were not able to
mount ubi with the saved data.
Having followed your instructions , we tried it and it works perfectly fine now.
Thank you again !

On Sun, Jan 17, 2010 at 2:44 AM, Artem Bityutskiy <dedekind1 at gmail.com> wrote:
>
> Hi,
>
> sorry, I am not sure understand the question.
>
> On Fri, 2010-01-08 at 16:46 +0530, Shweta Shetty wrote:
> > Hi,
> >
> > To test ubi2 we intend to use NANDSIM. However we are facing certain problems.
> >
> > From what we have understood, the method of using NANDSIM is :
> > 1>create an empty flash device (By default this uses the ram memory
> > but we can allocate other by the cache_file option)
> > 2>mount ubi on it
> > 3>mount ubifs on it
> > => (Here we can load the previously stored image)
>
> If you want to write some pre-created image (e.g., created with
> mkfs.ubifs/ubinize) or previously saved image (e.g., you dumped
> your /dev/mtdX to a file previously), then you have to do this _before_
> attaching the MTD device to UBI. IOW, you have to do this between steps
> 1 and 2.
>
> > 4>use it
> > 5>while unmounting save the image on permanant storage
>
> After you have unmounted everything, you can save it, yes.
>
> > So as we can see, though NANDSIM can be effectively used for
> > simulating flash , it is of limited use in our project for testing
> > mount time as every time only the empty device is mounted.
>
> No. You can write your contents there before mounting.
>
> > From the ubi code that we have now studied , there is a flag set for
> > an empty device and in such case , all the system does is that it
> > initialises all its data structures.
>
> It does this _only_ if you feed it an empty flash. Do not feed it an
> empty flash, feed it a formatted flash, then it will not initialize it.
>
> > Hence we cannot show the
> > performance of our project on NANDSIM.
>
> Well, of course in any case, performance is better shown on a real
> device.
>
> > Our we missing some crucial point?
> > We would be grateful for clarification.
>
> Not sure I clarified, because I did not really understand the question,
> but HTH.
>
> --
> Best Regards,
> Artem Bityutskiy (Артём Битюцкий)
>



--
Shweta Shetty
http://shweta-kaleidoscope.blogspot.com/
Humility is a strange thing. The minute you know you have got it you
have lost it.