Confirming Good DVD Burn

[akasocrates]

I'm on a Power Mac G5.  I use OS X 10.4.x DVD burn utility to back up my buckets to DVDs.  After burning, I go to Bridge and browse through the thumbs to make sure they're there.  Radomly, I'll open files into ACR.  That's all I do to confirm a good DVD burn.

Peter or anyone, is there anything specific you do to confirm that the burn completed flawlessly?  If it matters any I DO NOT yet use a DNG workflow.

Thanks.

[AndrewC]

The major CD-DVD burning packages for the PC include a byte-by-byte verification option, which is far more comprehensive than merely browsing the burned disk. There must be software for the Mac that includes this sort of option.

[peterkrogh]

The "compare" function is a good tool, but it does not check for everything. If the source file has a problem, it will just copy the bad file.

For an extra level of protection, you might want to run the files through the DNG converter (you can throw away the DNG files afterwards).  If Camera Raw can parse the files, it will convert without errors.  If the file has been corrupted, in most cases (the vast majority) the DNG converter will record an error for that file.

 (Sometimes, the internal data in the file will be corrupted, resulting in color bands in the image.  These files will not generate an error message in the DNG converter.  I have personally only seen this corruption straight out of the camera.)

BTW, I am currently running the DNG converter on my backup drives, as part of periodic drive exercise and file integrity confirmation.

Peter

[akasocrates]

Thanks.  That makes sense.  I might use a combination of both your suggestions.  I'll start adding "test running" the DNG converter as part of my workflow.

To Andrew's point, does anyone know if Toast 7 does some verification report of sorts.  Just to confirm that at least by their test, you get some diagnostic?  I can't quite mine that from their website.

Thanks a lot!

[peterkrogh]

Toast 6 did.  I can't imagine they would remove the capability.
Peter

[akasocrates]

Thanks, Peter.  Do you use any DVD burning software a la Toast?  Or do you simply use Finder in Mac OS X Tiger?

[David Anderson]

For an extra level of protection, you might want to run the files through the DNG converter (you can throw away the DNG files afterwards).  If Camera Raw can parse the files, it will convert without errors.  If the file has been corrupted, in most cases (the vast majority) the DNG converter will record an error for that file......

BTW, I am currently running the DNG converter on my backup drives, as part of periodic drive exercise and file integrity confirmation.

Peter,
Since I understand that you throw away virtually all your original Raw files in favour of archiving the DNGs, I assume that you use the DNG Converter to reprocess DNGs on your backup disks as a file integrity check. Is this correct? If so, it seems a rather non-intuitive but neat trick. Obviously, you would change the DNG Converter Preferences to avoid any embedded JPEG preview, thus greatly speeding up the integrity check.

David

[peterkrogh]

You got it David.  I also don't compress, and this also makes it go faster.

At the moment, I'm running it on my backup drives.  I've run through about 45,000 files with no error notifications.

Here's what I am doing.

1. Insert Drive, Run Disk Utilities note any errors (none so far)
2. Run Disk Warrior - note errors (none so far)
3. Run TechToolPro Drive tests, particularly surface Scan - (look for bad blocks - no problems flagged by TechTool)
4. Run DNG converter - note errors (none so far) and make sure the number of files converted matches what iView thinks should be on the drive (matching perfectly so far).
5. Rebuild iView Catalog - look for white icons instead of thumbnails - (none so far)

BTW, this will probably be about 2 weeks of data validation, given the fact that I am starting the next process only when I notice the previous one has ceased.  This could (and should) be automated. Hmm, maybe Beardsworth or Marc Rochkind will feel like making an application to automate the process.

I should have been doing at least the DiskWarrior/TechTool part every six months or every quarter, but in truth some of these drives have not been spun up for 2 years.  Nice to see that everything's cool (so far).  In the future, I vow to do at least 1-3 every quarter.  More often if I encounter any problems.
Peter