Re: [gentoo-user] testing a corrupt SD card

[Paul Hartman <paul.hartman+gentoo@gmail.com>]

On Thu, Feb 5, 2009 at 11:28 PM, Iain Buchanan <iaindb@netspace.net.au> wrote:
> Hi all,
>
> recently my SD card just went bonkers.  Unfortunately I lost a lot of
> photos on it (backups are useless until the data actually gets to the
> backup...) but fortunately I was able to use a program to recover about
> 170 photos.
>
> Anyway, I don't know if it was just static, shock, dead card, or phase
> of the moon, so I would like to see if the card is good before I
> continue to use it.

With any kind of memory or storage device, I would stop using after
the first sign of a problem. My personal experience says it only gets
worse. :)

Lexar has a free program for recovering corrupted/deleted files from
their cards, did you use that? Or something linux-based like photorec?
Anyway, you wrote over it so it's too late now. :)

I would try any kind of "torture test" you can think of on it. Also be
sure to unmount/remove and reinsert it a few times. I have encountered
cards that only work 1 out of 4 times they are inserted into the card
reader, etc. Maybe the contacts are worn if it's a few years old?

Some (all?) memory cards do wear-leveling/load balancing so when you
write to sector 13 it might not be the same sector 13 as last time, so
doing any kind of repeated error testing might be difficult. In fact,
if the card detects bad spots it may simply hide them from you. There
may be programmatic ways to bypass the card's wear-leveling, but I
don't know how.

Good luck! In case you can't get it working reliably, Newegg has an
8gb CF card for $19.99 & free shipping :)

Paul