CDfs is a file system for Linux systems that "exports" all tracks and boot 
images on a CD as normal files. These files can then be mounted (e.g. for 
ISO and boot images), copied, played (audio and VCD tracks) The primary goal 
for developing this file system was to "unlock" information in old ISO images.
For instance, if you have a multisession CD with two ISO images that both 
contain the file 'a', you only see the file 'a' in the second session if you 
use the iso9660 file system.

Because this installs a kernel module, you will need to rebuild the package
if you change kernels.