How can I fix corrupt image on SD card, my os is rasbpian wheezy 7 which got sluggish and I tried to fix it with running fsck ( on my pi and on another 3 linux machines) which did not fix my problems...
You can run a live Debian CD on a normal computer + USB SD card reader or a laptop with an SD card slow.
- Boot into the live CD.
- Plug in the SD card
- It should mount
- Copy what you need.
- Run a low level format ...
- Low Level format will force the SD card firmware to realign good sectors while discarding of bad.
- This might help sort the card out for a short while. But if its a its generic brand, this might only works once or twice and then into the bin because it will get worse, faster.
- Look for Genuine SD cards, preferably Class 8 or 10 as they are higher quality.
- Reinstall a new image to the NEW SD Card.
Sorry, thats the best you will be able to do. As with corruption, check disk might find it as OK, but in reality the bits are messed up. You would need to track down the binaries or files and replace them but you cannot guarantee if you fixed all the corruption, or if the file will actually be copied properly.
With SD cards, bad sectors are usually managed by the SD firmware, so its not like a traditional drive where you know that sectors xyz is corrupt and file 123 is on it, because SD firmware will try and relocate the sectors dynamically and attempt to fix the data as best it can, even if its corrupted.