Naked Science Forum

Non Life Sciences => Geek Speak => Topic started by: Tintin_Triton on 23/02/2010 14:03:55

Title: How can I find out what files are corrupted in a DVD?
Post by: Tintin_Triton on 23/02/2010 14:03:55
Hello guys!

I wrote a DVD of my family photos and videos, on a standard Moserbaer 4.7 GB DVD-R. The problem is I was in a hurry and somehow, the writing process got over, but while verification I pulled it out, and while test running it I got some bad and damaged sectors. I use Nero 7 Essentials, and used the Nero test drive to come to a conclusion. Surprisingly, the videos still run! It is only 0.5% bad, and 0.2% damaged

There are about 1500 photos in it though, and I will have to go through it entirely to find out which is corrupted. Better than that, I can make another DVD. But I just want to find out specifically which are damaged.

Hoping to get a crickey answer!
 
Title: How can I find out what files are corrupted in a DVD?
Post by: RD on 23/02/2010 17:08:37
Checksums are used to detect data corruption ... http://en.wikipedia.org/wiki/Checksum
But but they won't tell you where on the disc the error(s) is(are).

I'd burn a new DVD if I were you.
You can save the DVD's ISO image (http://en.wikipedia.org/wiki/ISO_image) on your computer, if you've got 4.7Gb free, and use it to burn another copy if the disc is faulty again.

Tip: if it is an important archive burn two DVDs from different manufacturers, rather than two discs from the same batch, just in case there was a manufacturing fault which affected all the discs in a batch, so you will still have a working copy.
Title: How can I find out what files are corrupted in a DVD?
Post by: Tintin_Triton on 24/02/2010 08:50:26
Uh... no. I know about that checksum, and I am sure while copying to another system, I will come across CRC (Cyclic redundancy check) error, and once that's done, I am sure my mom  will hold me responsible and call the firing squad.

I wanted to know which file exactly is corrupted, so your answer really didn't help.
 [???]
Title: How can I find out what files are corrupted in a DVD?
Post by: LeeE on 24/02/2010 10:03:16
If you can make another DVD then I assume that the original pics & vids are still on the HDD.  If this is so, and you were running Linux, you could simply run 'diff -rq' against the top level hierarchy of the two copies (assuming that the hierarchy structure on the DVD is the same as on the HDD) to see whether there are any differences.

I'm guessing that you're not running Linux but as diff is open-source I'd be surprised if it hasn't been ported to windows.
Title: How can I find out what files are corrupted in a DVD?
Post by: Tintin_Triton on 26/02/2010 08:23:04
It hasn't been ported to windows, I didn't find it. I am not using Linux, but now I doubt that my DVD writer might be at fault. But if at all anyone wishes to know where the error is, then how should he do it? Which file actually got corrupted?