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

    MMG_CTLFLAGS is a bit mask used to enable and disable proactive
    memory reclamation mechanisms. Beginning with OpenVMS Version
    7.2, you can control when memory is tested. This helps reduce
    the time between when you turn on the system and when you log in
    to an AlphaServer 4100 computer. Bit 2 in the parameter controls
    deferred memory testing.

    The following bit mask values are defined:

    Bit    Description

    0      Reclamation enabled by trimming from periodically
           executing, but otherwise idle processes. This occurs when
           the size of the free list drops below two times FREEGOAL.

    1      Reclamation enabled by outswapping processes that have
           been idle for longer than LONGWAIT seconds. This occurs
           when the size of the free list drops below FREELIM.

    2      Controls deferred memory testing:

           o  If the bit is clear (the default), OpenVMS tests
              memory in the background and not necessarily before
              the bootstrap process has completed.

           o  If the bit is set, all memory is tested by the end of
              EXEC_INIT in the system bootstrap process (that is,
              before IPL is lowered from 31).

    3-7    Reserved for future use.

    MMG_CTLFLAGS is an AUTOGEN and DYNAMIC parameter.