<< you can write dvd movies using a dvd-r, you can't on a dvd-ram
This is not true, most DVD-RAM drives can write single sided cartless DVD-RAM media that will play in most consumer set top DVD players as well as DVD drives found in desktops and laptops. We have 6 DVD-RAM drives in our office and I copy DVD movies all the time onto single-sided 4.7GB DVD-RAM media and play them in my ThinkPad T21 DVD drive. >>
I think it's very likely that you have one of the Panasonic LF-D311 RAMBO drives, which writes to both DVD-R/RW and DVD-RAM. DVD-R media is 4.7GB and cartless, DVD-RAM media is slightly larger, and is not available without a cartridge, nor could a settop player ever read the file format on DVD-RAM due to the drastically different way in which data is stored on it.