I'm reviving this old thread because something similar happened to
me today, similar to what Bruce reported. (Rob's case --- the initial
email of the old thread --- is different I guess, because his card
wasn't read even by his camera.)
Although I didn't loose any photos (I think), I hope this email
helps to shed some light into the problem, and help others to solve
similar issues. (Hopefully this won't happen to often...)
[Below is Bruce's reply to give the context, and then follow my
observations.]
On Mon, Mar 3, 2014 at 2:22 AM, Bruce Walker <bruce.wal...@gmail.com> wrote:
> [...] I shot some stuff and returning
> home I couldn't unload my card because it couldn't be read in my Mac.
> The Mac unmounted the card shortly after insertion saying it had
> damaged formating. And I couldn't convince the Disk Utility to repair
> it either.
>
> Can you see the card content when inserted into the K-3?
> [...]
> BTW, sadly I lost the content of that "damaged formating" card. I
> could see the images when the card was in the K-3 but nothing I did
> allowed me to extract that data, even over a USB cable. I was sorely
> pissed off.
For me however it was even more strange --- I have a Pentax K-30,
SanDisk Extreme 16 GiB:
* I've locked the card for read-only; (I always do this for
precaution, and as a habit because of OS X, which insists in creating
hidden files and folders even when though I just open a disk / card to
read it;)
* I've put the card in the laptop's card reader; (this was
extremely dumb of me, because I know that my card reader has issues
due to the Linux driver (or maybe the hardware?); usually I use an
external one...)
* mounted it in Linux, and successfully copied the files on my laptop;
* unmounted it, mounted another card, did the same as above;
* now, part of my "paranoid" workflow, I've mounted the card again
to make an MD5 sum of all the files;
* kaboom! the contents of the `dcim/yyy_xxxx` folders can't be
read, specifically the `yyy_xxxx` folders are seen as invalid file
types, thus I can't even list their contents; (below is the error for
the sake of completion; previously to that I also received some I/O
error, but this was "normal" for my laptop's card reader;)
FAT-fs (sdb1): error, fat_get_cluster: invalid cluster chain (i_pos 0)
* unmounted it, and tried it with a card reader (not the camera),
in an OS X laptop, the same...
* however as Bruce observed, all the photos were readable in the camera;
I didn't have enough space to make a full disk image (with `dd`),
thus I've decided to do a file system check (`fsck.vfat -f
/dev/sdb1`), which recovered "some" files. I say "some" files
because:
* the number does match the number of files I was expecting;
* none of the recovered files hashes matches the hashes of the
files I actually have; (the card contains photos that have
accumulated since last winter;)
* "visually" the photos do "look" alright; (they are DNG;)
Thus I can only conclude that the card reader damaged the card,
thus it's not the camera's fault. (Probably this happened to Bruce.)
Moreover it seems that the card "lock" feature is indeed just a "hint
for the software", and that some readers (hardware or software?) don't
care about it, just report it to the upper layer...
I also can conclude that the Pentax K-30 camera uses an
alternative way to access the file-system, or at least it accepts
invalid file-system meta-data without complaining...
> What I determined was that I had failed to reformat the SD card
> immediately after purchase.
My card was formated in camera a couple of times, thus I can
remove this as a probable cause.
Hope it helps someone,
Ciprian.
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