VMS Help Sys Parameters, STARTUP_P1-8  *Conan The Librarian (sorry for the slow response - running on an old VAX)

    STARTUP_P1 specifies the type of system boot the system-
    independent startup procedure is to perform. If STARTUP_P1 is
    " ", a full boot is performed; "MIN" indicates a minimum boot
    that starts only what is absolutely necessary for the operating
    system to run.

    STARTUP_P2 controls whether verification is set during the
    execution of the system-independent startup procedure. If
    STARTUP_P2 is " ", verification is not enabled; "TRUE" indicates
    that verification is enabled.

    Beginning in OpenVMS Version 7.2, if STARTUP_P3 is set to AGEN,
    the system executes AUTOGEN at the end of the startup sequence.

    STARTUP_P4 through STARTUP_P8 are reserved for future use.