How to Backup A Leopard DVD
[Thanks to MacNN Forums]
Make sure you've selected "Mac OS X Install DVD" on the left side of the Disk Utility window (the lower one is correct) and go to the menu bar in Disk Utility and from the 'File' menu choose "New -> Disk Image from disk 3s3 (Mac OS X Install DVD)…". It should be selectable if you've highlighted the disk in the Disk Utility window.
In the 'Convert Image' window give the image the same name as the Install DVD. For 'Image Format' select "read/write" (don't worry, you're not going to mount the image or write to it…the finished image just needs to be a .dmg, not a .cdr). For Encryption select "none". Save the image to someplace other than the Desktop. Since the image has the same name as the Install DVD mounted on the Desktop there is the potential for conflict if you try to save it to there. I recommend saving it to your Documents folder.
When you've finished converting the image it is very important that you DO NOT mount the image. Before you do anything else, select the image and do a 'Get Info' (Command - I) on it. In the 'Get Info' window, if the Disclosure triangle beside 'General' is not pointing down click on it to open it up and put a check mark in the box beside 'Locked'. This will lock the image and protect its' integrity (and bootability).
It is important to not 'go cheap' on the media and burn it at the slowest possible speed. My personal favourite for DVD+R DL media is Verbatim. Fuji or Sony would be my second choice. Everything else is crap IMHO.
Use Disk Utility for the burn. No Toast.
If you can, make the burn speed 2.4x. It'll take the better part of an hour to burn, but it should work.
