help with redhat 7.2 using device

hello,
i will like to know how can i use my cdrom and my hd in linux.
i go to /mnt/cdrom and says unknow device i mounted as
mount -t iso9660 /dev/cdrom /msn/cdrom
and dosent work, and also i am having problems with my other hd, but the deal with this one that i cannot see it in /mnt and i use the command mount -t msdos /dev/hdb /mnt/ hd

anyone pliz

thanks