cd-rom mount 문제입니다.. 도와주세요

mount /mnt/cdrom라고 명령을 치면
mount wrong fs type, bad option, bad superblock or /dev/cdrom,
or too many mounted file systems
(Could this be the IDE device where you in fact use
ide-scsi so that sr0 or sda or so is needed?)

mount -t iso9660 /dev/cdrom /mnt/cdrom라고 명령을 치면
mount block device /dev/cdrom is write-protected, mounting read-
only
mount No medium found

이런식으로 메세지가 나옵니다. 뭐가 잘못됐나요? 답변 부탁드립니다.