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

    On VAX systems, VIRTUALPAGECNT sets the maximum number of virtual
    pages that can be mapped for any one process. A program is
    allowed to divide its virtual space between the P0 and P1 tables
    in any proportion.

    If you use SYS$UPDATE:LIBDECOMP.COM to decompress libraries
    and the VIRTUALPAGECNT setting is low, make sure you set the
    PGFLQUOTA field in the user authorization file to at least twice
    the size of the library.

    At installation time, AUTOGEN automatically sets an appropriate
    value for VIRTUALPAGECNT. The value depends on the particular
    configuration-the type and number of graphics adapters on the
    system, if any exist. You cannot set VIRTUALPAGECNT below the
    minimum value required for your graphics configuration.

    Because the VIRTUALPAGECNT setting supports hardware address
    space rather than system memory, do not use the value of
    VIRTUALPAGECNT that AUTOGEN sets to gauge the size of your page
    file.

    Starting with OpenVMS Version 7.0, VIRTUALPAGECNT has been an
    obsolete parameter on Alpha systems. Note, however, that the
    parameter remains in existence on Alpha systems for compatibility
    purposes and has a default and maximum value of %X7FFFFFFF.
    SYSBOOT and AUTOGEN enforce this default value.

    VIRTUALPAGECNT has the AUTOGEN, GEN, and MAJOR attributes.