/sys$common/syshlp/helplib.hlb INSTALL, REPLACE, Qualifiers, /ARB_SUPPORT  *Conan The Librarian (sorry for the slow response - running on an old VAX)

       /ARB_SUPPORT=keyword

    On Alpha systems, overrides the system parameter ARB_SUPPORT for
    this installed image.

    The following table shows the keywords you can use with the /ARB_
    SUPPORT qualifier:

    Keyword     Behavior

    None        The obsolete kernel data cells are not maintained by
                the system. Fields are initialized to zero (or set to
                invalid pointers) at process creation.

    Clear       The obsolete kernel data cells are cleared (or set
                to invalid pointers) when the code would have set up
                values for backward compatibility.

    Read-only   The obsolete cells are updated with corresponding
                security information stored in the current Persona
                Security Block (PSB) when a $PERSONA_ASSUME is
                issued.

    Full        Data is moved from the obsolete cells to the
    (default)   currently active PSB on any security-based operation.