Jukka Marin <jmarin@pyy.jmp.fi> writes:

> >  Try `umount -R /cd0'.
> 
> Thanks, but
> 
> root@pyy / # umount -R /cd0
> umount: /cd0: Invalid argument
> 
> Well, at least I got a different error message ;-)

 Actually, looks like it fails because the drive has been already
 unmounted. Try to mount and unmount your drive again and watch what will
 happen.

Oleg