[maemo-users] Missing space on MMC2

[From: Marius Gedminas]

On Fri, Jun 06, 2008 at 08:18:09AM -0400, Torsten Hoefler wrote:
> On Fri, Jun 06, 2008 at 02:24:07PM +0300, Marius Gedminas wrote:
> > My N810 completely trashes the contents of the internal 2gb "memory
> > card" every couple of weeks or so.  I don't trust it *at all* any more.
> did you try to reformat?

That's what I do: reformat the card with the File Manager on the N810,
create a new swap file, then don't touch the card.  Later I will notice
that after a reboot my card is showing complete garbage:
http://mg.pov.lt/n810-fs-corruption.png

This has happened three or four times since I got my N810.

Initially I also had the problem with the FAT partition being a bit
larger than the device, but reformatting it with the file manager also
recreates the partition table, and it does that correctly.

Then I used the internal card to keep my valuable data.  Once I started
getting filesystem errors, rebooted and discovered that the partition
table was overwritten by the contents of a text file.  Since then I no
longer keep valuable data on the card.

> I'm kind of worried to do this because another
> filesystem might lower the lifetime of the flash-stuff by exhibiting
> different write patterns (and since it's soldered in, I don't want to
> destroy it faster than necessary). I'm actually even wondering if Nokia
> changed something in the vfat implementation or if this is standard vfat
> with the superblock in the first device blocks (seems to be very bad for
> flash-based memory).

I believe there's some balancing going on under the hood.  You use JFFS2
on a MTD device on raw flash; SD cards pretend to be a regular block
device that does write balancing in the hardware.  I believe the N810
has the internals of a SD card soldered on the mainboard.

Marius Gedminas
-- 
A witty saying proves nothing.
                -- Voltaire
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