Newer kernels as shipped with Linux-Mandrake bring an interesting feature for users frequently using floppy and CD disks. Installed or not as you specified in the miscellaneous dialog of the installation, it automatically mount and unmount medias as they are inserted or removed. This is quite handy as there is no more need to run mount or unmount each time.
If you ever wish to change that behavior, coming back to the good old manual mounting of medias, simply issue, as root, the command
supermount -i disable |
supermount -i enable |