Having a Red Hat 6 install with no GUI, and little else, made installing Netbackup clients from CDROM rather problematic. No definition for the CDROM drive was in /etc/fstab so "mount /dev/cdrom" wasn't going to work. Running "fdisk -l" did not show a CDROM and scanning and grepping dmesg revealed no clues. Then I found this command:
# wodim --devices
That worked (after running "yum install wodim"). Handy command!