Why are SD cards so FRAGILE ?

[sigmaX]

I installed Kathrin RC3 ... my SD stopped working in my zaurus. I just REINSTALLED SHARP ROM 1.40J just to find that it doesnt recognize my SD card either ...

It is a VIKING 512MB ...

I place it in my desktop card reader ... and there it is !!!

Anyway I try to format it (fat 16) on my desktop and I get a "Could not complete format" error the first time, but the second time it just formats it.

It seems to be the SD card !! why o hell are so fragile ?? I keep reading posts of SD cards going down everywhere on the web.

Is there any "Trick" to revive them ? Any software that can test them and give a more deep analysis of these small monsters ?

Regards,

[Chaos]

Maybe they're so fragile because of the size of them?

A CF card has an obviously hard shell. The SD cards bend a bit. They're thinner than floppies, and about 1/8th the area, but hold at most over 1000x the data. I know it's a bad comparison, but it gives you a bit of an idea of how small the parts inside them are.

Because of the size, they're easy to damage, and any damage effects more of the useable space on them then on a CF card.

[offroadgeek]

It may be how you (or others) use them.  I keep my 256mb SD card in my zaurus at all times... The only time I take it out is to swap it with my 512mb when I'm viewing videos taken from my video cam (it uses SD also), which I do maybe every couple months...?

[Zuber]

I doubt it is the fact that they are flexible etc.

Someone posted a link a while back with some endurance testing of memory cards. They did rather well SD included.

I think offroadgeek is right.

It is more to do with type of use rather than abuse.

[iamasmith]

I think if you read this artical it may suggest that it's not physical abuse that's causing problems with these cards...

http://news.bbc.co.uk/2/hi/technology/3939333.stm

- Andy

[VeeDubb]

I think a more intersting question is this. "Why is such an unreliable and flimsy format so popular?"  CF cards, which are nearly indestructible, are realy not that big.  frankly, I've never thought to myself, "God, I wish these damn CF's were smaller."

[xarope]

hmm, strange, I've had a toshiba 128MB, 2x panasonic 256MBs and a 1GB rebadged Panasonic, with no problems, swapping them between phone (treo 600), Sl5500D, C760, and my fujitsu p5010 with no worries over the last 3 years (well, when I first bought the SL5500D, it was 3 years ago).

[rgrep]

Is there any "Trick" to revive them ? Any software that can test them and give a more deep analysis of these small monsters ?

I recommend using the 'badblocks' command to test cards.

I had a lot of trouble with a "fragile" SanDisk 256MB SD card.  The filesystem would corrupt itself every so often and some or all of the files on the card would be destroyed.  I finally realised I could just use badblocks to check the card, and I found that only the first 108MB of the card was free of bad blocks.  After repartitioning the card to only use this first 108MB I didn't have any more probems.

I ended up returning the SanDisk card and bought a Kingston 512MB SD instead.  I made sure to run badblocks on the Kingston card as soon as I got it.  The scan showed no bad blocks and I haven't had  any problems with it whatsoever.

To run a badblocks scan (in read-only mode) on your entire SD card, and have it write a list of suspect blocks to /tmp/sd.bad, type the following at the shell prompt:

Code: [Select]

umount /dev/mmcda1
badblocks -s -v -o /tmp/sd.bad /dev/mmcdaYou can also run a read-write scan (which will DESTORY all data on your card) by adding the -w command-line switch.  There is also a "non-destructive" read-write mode which will preserve your data, but use that at your own risk.

[Bundabrg]

Hmmm, here are my experiences.

C860, Katherin RC3 pdaXrom.

I bought a 1G Sandisk sd. Formatted it to ext2.

Dmesg is always full of i/o errors and "-W- Don't Delete" messages. If i copy a large file to the card it gets corrupt or I lose l files and have to remount. Havn't tried mounting with async, but running a while 1 do sync sleep 1 seems to help with big files.
Then it started complaining that it was FULL, with 500mb free. Keep in mind I,m using the original partition table with fat16 id.

Enough is enough. I did the following:
  - unmounted it
  - ran fdisk on it. Emptied the partiton table (press "o").
  - noticed that if I created a partiton, all these wierd 0 length partitions were created.
  - Therefor created 1 partition, but as partition 4. This gave me a single partition 4 with none of the wierd partitions.
  - ensured id was linux
  - wrote table.
  -  modified fstab to use partition 4, noauto
  - rebooted... just in case
  - formatted it to ext3
  - edited fstab, set to auto
  - mounted
  - downloaded gentooForZaurus, a 112Mb file... IT WROTE!
  - extracted it...... NO ERRORS.

ymmv , havn't tested it long enough to be sure my problem is solved but I thought this may help someone.

- Bundaberg

[Chaos]

I think a more intersting question is this. "Why is such an unreliable and flimsy format so popular?"  CF cards, which are nearly indestructible, are realy not that big.  frankly, I've never thought to myself, "God, I wish these damn CF's were smaller."

Most SD cases are the same size as CF cases, in my experience... I think it's, in the Zaurus, the fact that many people would rather have CF network card in, in most cases. In the case of other, SD only devices, I'd bet that it's just because the manufacturer wants to make the device the smallest that it can. Most people think that the smaller a device is, the sexier it is.

Can't wait until cellphones are so small that they're just a small headset (i.e. earpiece and microphone, with voice interface  ).

[iamasmith]

- noticed that if I created a partiton, all these wierd 0 length partitions were created.

That's an ARM compiler bug generating problems with the routine in FDISK that determines if a partition slot is empty. To fix this fdisk must be compiled with -mstructure-size-boundary=8 as a GCC flag.

It's quite important that you use a version of fdisk that doesn't have this problem. You may want to check out the fdisk212ae2fsprogs135.ipk on the Sharp ROM forum under the 'New version of fdisk...' thread. This should correct the fdisk issue and it has a version of e2fsck that doesn't scrap the ext3 journal if you force a check.

- Andy

[doc]

Another thing you should setup with your Z when mounting SD cards...

Add the "noatime" option to the /etc/fstab in the mount line for your SD.

This will eliminate many writes to the SD card that are done when a file is "accessed."  That way when you view files like images, documents, etc. that you have on your SD card, it won't perform a write to update the access time on the file.  That will give your SD card a longer life, as the SD cards will wear out faster when you write to them often.

[jamesannan]

Ok, so my SD card seems to have just gone bad...Zaurus hanging, works fine when I take out the card and reboot but cannot restore a full backup and even putting in the card seems to bugger things up.


So I'm running badblocks -svw, and  it is taking for ever. At this rate it is going to be all night, and then some. (512Mb card). Does this mean the card is completely buggered? I'm puzled as to how it can have been fine one day, and collapse the next - I didn:t even put it in the washing machine or anything, it just sits in the zaurus all day.

James

[doc]

What brand?  Same deal happened with my SanDisk, so I bough Viking, and it has lasted longer but the jury is out as it has only been a few months.

Do you have another piece of hardware, like a 6-in-1 card reader or camera to check it out, or is the Z your only way of reading the SD card?

If you need to reformat it, you might be able to go to a camera store and talk them into letting you put it in a demo camera to reformat it.

[jamesannan]

No SD card reader but will probably buy one this weekend. I'm pretty convinced the card is knackered but no harm in checking again - the card reader will come in handy anyway, getting large files (dictionaries etc) on the SD card was a bit painful.

The 860 is working fine now with just a CF card.

James