Hi Yoshiki,

>     umount /mnt
>     I get "device is busy" error.
>
>   * close Squeak and try unmount again.  I can unmount the file system
>     this time.

The unix vm caches the last open directory to speed up directory
searches.  (Because of the way the image searches directories, this
caching results in linear time instead of exponential with the size of
the directory.)  If you change away from /mnt in the file list you
should be able to umount from the terminal.  If not, ignore this
entire message. ;-)

Cheers,
Ian