detlef@MD97600:~$ lsof /dev/cdrom
COMMAND     PID   USER   FD   TYPE DEVICE SIZE NODE NAME
gvfsd-cdd 17172 detlef    7w   BLK   11,0      6278 /dev/scd0
rhythmbox 17180 detlef   31w   BLK   11,0      6278 /dev/scd0
rhythmbox 17180 detlef   32u   BLK   11,0      6278 /dev/scd0