Writing data DVD sometimes results in lost data.

Question

Hi there
First a bit of background on the Mac in question. We have an G5 running Leopard (10.5.8) here that we use as a file server. Operator copy files off the servers, work on them locally, and then copy them back when finished. After a job is finished and invoiced, 'inactive' client files are writtien onto DVD for our archive, and deleted from the file server.
We have had a few instances where a DVD has been written, the session closed, and no errors have been raised by the OS – however, when going back to some of these DVDs, individual files have not been copied. The files are not corrupt, they simply have not been written. For example, A folder containing a client's publication exists, but not all of the InDesign files contained therein, and perhaps some image files are being lost that are contained within a 'links' subfolder.
I have checked the filenames of the offending items, and there are no illegal characters being used in the filenames or anything obvious that I could use to chase this problem down. There have been occasions that there have been files on the server (most of the time originating from Windows PCs) that for some reason have the permissions set as 'read-only' and on rare occasions some mac files have also had the same problem.
In my mind, if it were a hardware issue, (i.e. the DVD drive going bonky (technical term)), then the OS would report back with a writing error either during the writing phase or after the session closes, and the issue would become more and more common as the hardware fails. That's not the case.
Then again, if it were a software issue, I would expect it to happen much more often - but given that a huge percentage of the disks write OK, and none of the offending files have illegal characters, I cant see why it would be a software issue (unless it could be down to permissions errors listed above – feel free to comment on that possibility.
So what I'm really after is this: At the moment, after we write a disk, we have to view the original folder's contents, and compare them to the written DVD using 'Get info' to ensure that the amount of items in a given folder (and the amount of bytes written) tally up. Is there a good software solution that would automatically check the disk after writing to compare the source and destination folders?
I looked at rsync, but found that it only compares folders, and DVDs cannot be mounted for it to work. I have also looked at using diff, but to be honest, we are all from a design background here, and none of us have any background in command-line Unix. Terminal scares us.
So – any ideas for freeware/shareware? My searches have come up blank, and my attempts to write an automator script also came to nought.
Thanks in advance.

Answer 1

I am also trying to write an automator app that handles the disk checking for me.
You may want to post your automator question in:
https://discussions.apple.com/community/mac_os/mac_os_x_technologies
Perhaps you should post this whole question in the technologies forum.  This is an odd problem.
I did find some comparision apps.  The dvd icon works like a folder. You would compare dvd icon to a folder.
Compare Folders. 
http://download.cnet.com/Compare-Folders/3000-2248_4-10317614.html
I have this app. Looked easiest for your needs.  Not sure it would spot one character getting mangled in copied files.
The author has stopped supporting the app
Folder Compare
https://itunes.apple.com/us/app/folder-compare/id535348544?mt=12
I haven't tried, but example looked interesting.
Kaleidoscope
Use Kaleidoscope to spot the differences in text, images, and folders.  Folder compare example looked a little weak to me.
http://www.kaleidoscopeapp.com/
FileMerge
The light grey entries means the files compare.  The bold entries mean the folders did not compare on these files.
It's free and part of the developer tools with xcode.