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Hi all, I have an transcend sd card in my embedded device.when i am running an application to test it gets corrupted once in 100 times or less... My sd ...
  1. 11-11-2009 #1
    durga prasad
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    Question SD card partition corrupted

    Hi all,
    I have an transcend sd card in my embedded device.when i am running an application to test it gets corrupted once in 100 times or less...
    My sd card test application shall mount the sd card writes the 1 kb file to sd card and unmount the sd card and again mount the sd card reads the 1 kb file and compare with file written into sd card and unmounts the sd card.The sequence of steps is as follows:-
    mount /dev/mmcblk1 /mnt/sd
    write the 1 kb file
    umount /mnt/sd

    mount /dev/mmcblk1 /mnt/sd
    read the 1 kb file and compares
    umount /mnt/sd

    if i perform the above test and power off and power on the embedded device and perform the test again if we do like this for 40-50 time the partition of the sd card is getting corrupted and i am not able access the content of the sd card either in linux or windows pc...I need to format the sdcard to access it again...

    Below i am attaching the dmesg of the error...

    I would like to find a solution for why the card is getting corrupted...


    Thanks in Advance...
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  2. 11-11-2009 #2
    Rubberman
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    It could be the card itself. SD flash memory has a limited number of write cycles to each sector. Decent cards will remap sectors automatically in order to balance the writes over time so that you won't hit a bad sector too quickly. In fact, many SD cards only allow about 10,000 write cycles to any cell. Although that might seem like a relatively big number, it is a limit that can be reached pretty quickly. So, try a new card or one from a different manufacturer, and don't try to use the cards for a lot of rewrite activity. If your embedded system needs to do a lot of writes, then you might want to look into 1" hard drives. There are a number of those available with 1+GB of storage in a CF form factor.
    Sometimes, real fast is almost as good as real time.
    Just remember, Semper Gumbi - always be flexible!
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  3. 11-12-2009 #3
    durga prasad
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    No i am using the new sd card and of different manufatures but i am getting the same problem..
    can any one know how can partition of the sd card can corrupt...
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  4. 11-12-2009 #4
    Rubberman
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    Well, have you sync'd the file systems also, before you umount it? Try this:
    Code:
    mount /dev/mmcblk1 /mnt/sd
write the 1 kb file
sync
umount /mnt/sd
    Sometimes, real fast is almost as good as real time.
    Just remember, Semper Gumbi - always be flexible!
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