reliability SD card

I design linux embedded system for video operations. Video file is saveing on SD card. I've problem with reliability file system. When user take off card or system lost power during write operation file system is breaking down. Have you any idea how protect file system before corrupt. Of course I could build power sustain system, but I couldn't protect my device before take card off. This card must be readable on computer with windows operating system.

regards

Kamil

0 Former Member over 15 years ago

Use a journaling file system or make a small hold-up circut that trigger an finish write before system losses all power.
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0 kolumb over 15 years ago in reply to Former Member

Unfortunately it doesn't help. I wrote that user can take off card during write operation, and it must be windows readable file system. I try using ext2/ext3, but it break down also.
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0 Former Member over 15 years ago in reply to kolumb

But you have cardholders with a switch that gives a signal when the card are pressed down for release, but still in contact with the tabs - use that signal to unmount the filesystem. But, EXT3 should not break if you just recover and check the journal when remounting the filesystem - this is the idea of journaling filesystemes. The filesystem writes a note that before and after the write it erases the note - this is the key to restore no matter when a error occures. One other thing is to mount the file system in read-only and use a ram-drive. when changes are made then remount the file system in read-write mode. This is kind of comon in embedded applications wher the filesystem rarly needs to be changed during normal use.
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