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

    (VAX only) PHYSICALPAGES sets the maximum number of physical
    pages of memory to be used on the system. Decreasing this
    parameter allows you to test smaller configurations of memory
    without the need to remove memory boards.

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

    PHYSICALPAGES is an AUTOGEN parameter.