On recent Linux kernels you can write to your (SCSI) CD! The system should recognize your DVD as a writeable device, and allow you to write to the "sr" device.
The patch below is no longer needed. It is still here for those who cannot upgrade to newer kernels and for archiving.Andrew Lines (lines@cs.caltech.edu) wrote a short "how to install this patch". I've now had some feedback from people with the MATSHITA drives. V2 of the patch also works for them. :-) . V3 of the patch adds Support for the Yamaha DVD RAM drive (CRW4416S). V4 of the patch patches cleanly into 2.2.12. V5 removes the Yamaha support again: It's not a DVD-RAM drive.
Good news! The patch went into 2.2.13, so instead of going through applying the patch I recommend you now just upgrade to 2.2.13 instead. You can still read Andrews work, but you can skip the "apply the patch" step.....