VMS Help INITIALIZE, Parameters  *Conan The Librarian (sorry for the slow response - running on an old VAX)

 device-name[:]

    Specifies the name of the device on which the volume to be
    initialized is physically mounted.

    The device does not have to be allocated currently; however,
    allocating the device before initializing it is the recommended
    practice.

 volume-label

    Specifies the identification to be encoded on the volume. For a
    disk volume, you can specify a maximum of 12 ANSI characters;
    for a magnetic tape volume, you can specify a maximum of 6
    alphanumeric characters. Letters are automatically changed to
    uppercase. Compaq strongly recommends that a disk volume label
    should only consist of alphanumeric characters, dollar signs ($),
    underscores (_), and hyphens (-).

    To use ANSI "a" characters on the volume label on magnetic tape,
    you must enclose the volume name in quotation marks (" ").  For
    an explanation of ANSI "a" characters, see the description of the
    /LABEL qualifier.