VMS Help MOUNT, Qualifiers, /UNLOAD  *Conan The Librarian (sorry for the slow response - running on an old VAX)

       /UNLOAD (default)
       /NOUNLOAD

    Controls whether or not the disk or magnetic tape volume or
    volumes specified in the MOUNT command are unloaded when they
    are dismounted.

    Example

    In the following example, the volume labeled OFFENS is mounted
    on DKA1 with the /NOUNLOAD qualifier so that it can be dismounted
    without being physically unloaded. MOUNT also assigns the logical
    name STRAT.

    $ MOUNT/NOUNLOAD DKA1: OFFENS STRAT