tobias@naboo:~$ sudo mount -t iso9660 /dev/sr0 /mnt
mount: /dev/sr0 is write-protected, mounting read-only
mount: wrong fs type, bad option, bad superblock on /dev/sr0,
       missing codepage or helper program, or other error

       In some cases useful info is found in syslog - try
       dmesg | tail or so.