mount -F cdfs -o cdcase /dev/dsk/c0t4d0 /
mount-point
where mount-point is the directory over which you wish to mount the CD-ROM. The device designation /dev/dsk/c0t4d0 may vary.
umount /dev/dsk/c0t4d0
Again, use the appropriate device designation for your hardware.
LispWorks Release Notes and Installation Guide - 23 Dec 2011