Hi all,

I originally found this forum when I had some issues with a failed drive (PCB failue) which was, I am pleased to say, resolved by a 'pro' member.

I have a slightly different issue now but think this is still the place to ask the Q, if not please let me know.

So...I have ~ 50,000 jpeg image files stored on HDD (now a RAID1 mirror using FreeNAS) I also now have backup on external USB drive and I even burn to DVD as well - I got pretty paranoid.

Recently while going through some old pictures I noticed that some of the jpeg have become 'corrupt'. They will display perhaps the 1st 20% of the file in a viewer and then the rest is blank or a repeating pattern. They were NOT always like this. I dont like that this is happening and was hoping that others here may have suggestions. I do not like to think that overtime the problem gets worse I have the following Q's

1) Are there any known tools that can, at least attempt, to fix this or are these images gone? Is thsi a snakeoil industry?
2)Is this likely to be caused by a single 'flipped' bit on the disk? Is it more likely to happen at write time or just decay over time on the media?
3) Would the use of ZFS filesystem and or ECC memory help prevent or even eliminate this sort of problem?
4)Can I determine how big this problem is without eyeballing 50,000 files
5)If the answer to 4 is NO how can I prevent these broken files trashing the possibly good copies I have on backups.


Thanks for any help and or advice. I am reasonably tech competent and can use tools in different OS and follow instructions.

I would say it is generally not possible to "fix" broken JPGs (that is, if they are corrupted or missing some data). There are some ways to minimize the damage but obviously lost data is lost. Furthermore, I am not aware of any software that exists for working with repairing damaged JPGs.

In your case I would first try to figure out what is going on. If the files are indeed damaged then either the media they currently reside on is having problems or some media they were copied from in the past was having problems and they were copied in a damaged state (or I guess some other more bizarre problem, but point being files don't just spontaneously "flip bits" or whatever)

So, I would start by taking one of these files that you know is damaged and examining it with Winhex or similar to see if you can tell what is going on with the data.

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You don't have to backup all of your files, just the ones you want to keep.