Corrupted photo files

[bakubo]

I have been looking through my monthly folders of out-of-camera photos from digital cameras going back almost 12 years. This morning I discovered that some of my Minolta D7i jpeg files from 2002 that I have backed up are corrupted. I have 3 1tb external hds and I have checked all 3 and these same photos are corrupted so it must mean that either when the original copy was made to these hds the photos got corrupted or the earlier, smaller external hd also had corrupted copies. I use backup software that does file verification, but these really old ones from 2002 were probably first copied from the computer I had at the time using regular Windows Explorer since I only had a few photos then. I still have the old 120gb external hd and 160gb external hd back in Austin (I am in Japan now) so these old 2002 files are on them too. Next time I will check and I hope these photos are okay on those hds. Fingers tightly crossed. I hope these are the only ones. Strangely, only 5 in the folder are corrupted out of a total of 57. Also, strangely, only D7i jpeg files are corrupted. The folder also contains some jpegs from an Olympus D-510Z and those are all fine. Of course, I am sure that is only a coincidence since I can't see any possible connection.

All this does make me feel nervous though. I wonder if all my other photos, including raw, are okay?

[mvanrheenen]

That's unfortunate Henry. Hope the other discs contain non-corrupted images.

Although I cannot help you with recovering the corrupted images, I can offer you (and everyone reading) some advice on how to prevent files getting corrupted over time or during transport (copying, doenloading etc.): use parity control.

In short, parity control is a technique which can be used to verify the integrity of networkpackets/files after transport. This gives you a certain level of insurance that your files are as they were when you created them. At any time you can verify the integrity of your images and if some are corrupted, you can restore them to the state they were in when you have created the parity files. These parity files will take up some of your discspace, but that should be a small price to pay in this case.

In practice, before you copy the images from your computer to a back-up location, create the parity files with software which is available for free. Then, copy or back-up your images and the parity files together where you want to. Then, regularly verify the integrity of the images using the software and parity files.

It isn't the end all/be all of keeping your files in tact, but it will reduce the chances the images will become corrupted after a failed transport.

There is free software available with which you can make these parity files. Google "QuickPar" for example.

Hope it helps.

Mark

[Greg Beetham]

Back in 2002 Henry you probably were using a FAT32 machine, 1TB disks would be formatted in NTFS for sure using a later model OS. I'm guessing your old file manager/OS/program at some stage couldn't/didn't write to NTFS disks properly or some similar type event.
Greg

[mvanrheenen]

NTFS was present from Windows NT 3.51 onwards and was designed in 1993. So unless Henry was using Windows 9x/ME or a non-Windows OS at the time, I don't think incompatibility between file systems would've caused this.

File integrity degridation is more common then one might think. Multiple download/copy actions using the samen file or just simple old storagedevices may have caused this. Interrupted transport with non-CRC compatible protocols could result in these situations too.

Whatever the cause, top priority should be trying to prevent the same thing from happening in the future.

Mark

[bakubo]

Mark, thanks for the parity suggestion. I will look into it.

Greg, I have been using NTFS on all my computers since about 2000 and my first external hd, the 120gb one bought in 2003, was also formatted to use NTFS.

I discovered the 5 corrupted jpeg files yesterday morning when I was using a program to look at the folders. It creates thumbnails to view and for those 5 files it couldn't. I then used Windows Explorer and it also couldn't generate thumbnails for those files and when I tried to view the whole file I would only be able to see half or less of the full image. All of these OOC files are also on my old USB 2.0 120gb and 160gb external hds in Austin so I am hoping that the files are okay on them. I know that they were transferred from the card to the computer I was using at the time okay since I, of course, looked at all of them back then. I have looked at the folders containing the corrupted folders at other times after that, but I don't know if I have since transferring everything to my current 3 USB 2.0 1tb hds. I didn't buy all 3 at the same time and do the transfer at the same time. I bought one and copied the files from the 120gb + 160gb to the first 1tb hd. Later I bought another 1tb hd and copied files from the first 1tb to it. Later I bought another 1tb and copied the files to it from one of the earlier 1tb hds.

What I have been doing since yesterday morning is to use the program to go through all my OOC folders and have it generate thumbnails for all photos. I have 50k+ OOC files so it takes awhile. I have looked at most of them now and I have only found about 10 jpeg files, all in the folders from about 10 years ago, that are corrupted -- at least the program was not able to generate a thumbnail. Of course, being able to generate a thumbnail is not a guarantee that the file is okay, but I am pretty sure the others are okay. I go back and reopen old OOC files, especially raw files, from the last few years from time to time and have never encountered a problem. These old jpegs from a decade ago though don't get looked at much.

[Greg Beetham]

Yes I would have to agree Mark; it was just a thought, if you go back that far (1993) you would probably have to include HPFS in the mix as well although Microsoft phased out any support for that with the advent of NT4, but as usual there is/was overlap etc. but in any case NT wasn’t mainstream through the nineties, it was all FAT16 and FAT32 for personal desktops via Win95, Win98, ME etc. with NTFS finally becoming mainstream in 2001 with the introduction of WinXP.
I would tend to lay the blame for file copy corruption at the feet of security features built into the later OS’s, (file attributes and permissions), and throw into the mix virus checkers and firewalls it’s a wonder any files get transferred without foul-ups.
Greg

[mvanrheenen]

You might have something there Greg. It wouldn't be the first time security "features" fouled up files because the recognition algorithms or heuristic scans mistake common files for security risks.

Good luck sorting everything out Henry!

Mark