Well, you are right, it is /dev/cdrom, but I'll be darned if I can find it anywhere in /dev/ . . . It works OK on the DVD, altho it says "no freedb found" in the player window while it is running. However, when I try to run it in CD-R device, it wants me to fill in title of disk, artist, name of at least one track, and then it wants to classify this as to type of music, and when I do that it then wants to put all this info into a directory I have not created, and when it discovers that, it will not work; whereas with DVD other than the error about no freedb found, it just plays the selected track.
So it would appear that it is associated already with both drives, but I surely don't see how to do it, since neither is listed as CD-ROM; one is DVD and the other is CDrecorder under properties for the two when I click their icons.