Using "mount -t msdos" is deprecated; the canonical name of the
filesystem type is "msdosfs". There has been some compatibility
glue in mount(8) to silently convert "mount -t msdos" to "mount
-t msdosfs" for a while now, but using the deprecated name may
cause errors when someone tries to "umount -t msdos". The later
doesn't work at all.

Noticed by: rodrigc, long ago