@enzotib mentioned the following command
sudo mount -o remount,rw /cdrom
Does this imply I can mount a CD or DVD in rw mode and use like a (real) filesystem? Does this work with the popular ISO-9660 filesystem, which is read-only by design? Will this create a multsession CD with one session per change (or per mount)?
Would this work (differently) on a ISO image file on a read/write filesystem?