Date: Mon, 10 Nov 2008 11:09:15 +0100
From: Pavel Machek <pavel@suse.cz>
To: J?rn Engel <joern@logfs.org>
Cc: kernel list <linux-kernel@vger.kernel.org>
Subject: Re: ext2/3 vs. kingston 32G SD card
Message-ID: <20081110100915.GB30504@atrey.karlin.mff.cuni.cz>
References: <20081104110225.GB4514@atrey.karlin.mff.cuni.cz> <20081104114733.GA16036@logfs.org>
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> On Tue, 4 November 2008 12:02:25 +0100, Pavel Machek wrote:
> > 
> > I got 32GB kingston SD card, and am using it with ext2 for storing git
> > trees etc.
> > 
> > Unfortunately, every time I run fsck, I get rather nasty corruption. 
> > I switched it to ext3 now, but I believe I have seen corruption even
> > on volume marked clean, which should be impossible from user error.
> > 
> > If I suspect wrong block device, what are useful tests to run there?
> 
> Not likely in your case, but a number of counterfeited devices are on
> the market.  They contain a much smaller chip inside than is advertised
> plus some logic to return 0x00 when reading from non-existent memory.
> 
> To test for this, simply write 0xff to the complete device and read it
> back.  'hd' is useful, as it compressed the output into four lines for a
> good device and a bit more when you bought crap.

Ok, I switched to ext3 and the card seems to behave now. It seems to
hold the data, so it is probably not fake :-).
									Pavel

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