ARB_SUPPORT

   (Alpha and Integrity servers) The Access Rights Block (ARB)
   compatibility option, the ARB_SUPPORT system parameter, is
   provided specifically to support products that have not yet been
   updated to use the new per-thread security Persona Security Block
   (PSB) data structure instead of the ARB. Changing the value of
   ARB_SUPPORT from 2 or 3 (the default) to any other value can
   affect the operation of these products.

                                  NOTE

      VSI recommends that all Version 7.3-1 systems have the
      ARB_SUPPORT parameter set to 3 (the default). Do not change
      the ARB_SUPPORT parameter to any other value until all
      products dependent on the ARB and associated structures
      have been modified for the new environment.

   The following table describes ARB_SUPPORT parameters:

   ARB_SUPPORT
   Parameter         Value    Behavior

   ISS$C_ARB_NONE    0        The obsolete kernel data cells are not
                              maintained by the system. Fields are
                              initialized to zero (or set to invalid
                              pointers) at process creation.

   ISS$C_ARB_CLEAR   1        The obsolete kernel data cells are
                              cleared (or set to invalid pointers)
                              when the code would have set up values
                              for backward compatibility.

   ISS$C_ARB_READ_   2        The obsolete cells are updated with
   ONLY                       corresponding security information
                              stored in the current PSB when a
                              $PERSONA_ASSUME is issued.

   ISS$C_ARB_FULL    3 (de-   Data is moved from the obsolete cells
                     fault)   to the currently active PSB on any
                              security-based operation.

   ARB_SUPPORT is a DYNAMIC parameter.