Since a single medium changer can service many devices within a library, this
option provides a way to direct a medium changer operation to a particular
device.
The medium changer is to perform the requested operation to the
device specified.
The device is the numeric sequence of a drive within a library and
defaults to 1 if not specified.
For example:
mccntl -d /dev/mc/mc2 -l 3 -t 2
This command instructs the changer /dev/mc/mc2 to load the medium
from storage slot 3 onto the second device in the library.