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

    If class scheduling is enabled, MAXCLASSPRI sets the maximum
    range in the priority range of class-scheduled processes.

    This special parameter is used by Compaq and is subject to
    change. Do not change this parameter unless Compaq recommends
    that you do so.

    MAXCLASSPRI is a DYNAMIC parameter.