I did test some DVD-RAM disks and drives a while ago and,
compared to MOD, they are underwhelming. Most disks
were not very reliable and close to the error margins.
I don't think DVD-RAM is suitable as the archival medium
it was designed to be. The second problem is that it
is not widely used. I woukd say DVD-RAM is basically
a technological dead-end.
Panasonic video recorders used DVD-RAM.
I guess one appeal was the ability to continually re-use a single disc
for "throwaway recording". However the advent of hard drive recording
boxes made that somewhat redundant. It did however reveal a truth
about DVD-RAM reliability. I left a DVD-RAM type-4 cartridge in a
video recorder, recording & deleting about once a week for a relative
over 2 years. At the end of 2 years the machine rejected the disk.
That pretty much told me all I needed to know about the media.
Blu-Ray replaces DVD-RAM.
The blunt reality is, every "audio based" backup media sucks. DAT
sucked (drives poorly calibrated). CDR sucked big time with initial
dye problems, laser calibration issues and need to use a freezer after
6 months. DVD-RAM was a halfway attempt at improving on DVD, I recall
it verified-after-write.
Sadly we "lost" Magneto Optical which is a wholly more robust system -
as long as the media is made correctly and the drives are up to
scratch. The 3.5" MOD stopped at 2.3GB - actually quite enough for
most critical backup applications. A hard drive can then be used for
general backup, eg, video, music, etc.
We lack a cheap archival grade backup system - basically the idea is
multiple hard drives, SD, USB-Flash. You then move on to the next
media instead of trying to achieve a lifelong media type. There is a
robust Blu-Ray, Panasonic ADA however I think that may go the way of
UDO. The simplest can be offsite cloud backups. That said, I still
favour MOD for those critical backups as well as SD.
DVD-RAM was good for a quick backup of bulk for not much money. Hard
drives I hate as a backup device because they are simply not rugged.
SSD systems do offer robustness and their price falls all the time.