/sys$common/syshlp/helplib.hlb INITIALIZE, Qualifiers, /MAXIMUM_FILES  *Conan The Librarian (sorry for the slow response - running on an old VAX)

       /MAXIMUM_FILES=n

    Restricts the maximum number of files that the volume can
    contain. The /MAXIMUM_FILES qualifier overrides the default
    value, which is calculated as follows:

    (volume size in blocks)/((cluster factor + 1) * 2)

    The maximum size you can specify for any volume is as follows:

    (volume size in blocks)/(cluster factor + 1)

    The minimum value is 0. Note that the maximum can be increased
    only by reinitializing the volume.

                                   NOTE

       The /MAXIMUM_FILES qualifier does not reserve or create
       space for new file headers on a volume. The file system
       dynamically allocates space as it is needed for new headers.