(Alpha and Integrity servers) IMGREG_PAGES is the number of
    pages to reserve in P1 space for images to be installed with
    shareable address data. If IMGREG_PAGES is set to 0, no images
    are installed with shared address data. The default is 10,000
    pages.

    For more information, see the INSTALL section in the HP OpenVMS
    System Management Utilities Reference Manual.