DVDs have evolved over the years and the DVD-RAM is now rarely seen. However I had one recently that had failed for the user. This had happened due to a mixture of failed sectors, and also the disk represented itself as blank.
To recover, first an image was made using special CnW hardware for blank or formatted disks. This then showed a FAT32 disk structure. The software would not recognise this initially, partly due to the 2048 (0x800) byte sector size.
CnW software has now been updated to process the DVD-RAM sector size, and files could then be read from the disk. The only problem was that a few sectors could not be imaged. By looking at the log, and sorting on ‘start sector’ it was clear which files were incomplete due to the failed sectors. Overall, most of the files were recovered correctly.
To physically read a DVD-RAM disk the DVD drive has to be compatible. On a quick test of 6 drives, 3 were found to be compatible, and 3 were not.