TMSCP_SERVE_ALL is a bit mask that controls the serving of tapes.
    The settings take effect when the system boots. You cannot change
    the settings when the system is running.

    The serving types are implemented as a bit mask. To specify the type
    of serving your system will perform, locate the type you want in the
    following table and specify its value. For some systems, you may want
    to specify two serving types, such as serving all tapes except
    those whose allocation class does not match. To specify such a
    combination, add the values of each type, and specify the sum.

    The following table describes the serving type controlled by each bit
    and its decimal value:

           Value
           When
    Bit    Set     Description

    Bit 0  1       Serve all available tapes (locally attached and
                   those connected to HSx and DSSI controllers).
                   Tapes with allocation classes that differ from the
                   system's allocation class (set by the ALLOCLASS
                   parameter) are also served if bit 3 is not set.

    Bit 1  2       Serve locally attached (non-HSx and non-DSSI)
                   tapes.

    Bit 2  N/A     Reserved.

    Bit 3  8       Restrict the serving specified by bit 0. All tapes
                   except those with allocation classes that differ
                   from the system's allocation class (set by the
                   ALLOCLASS parameter) are served.

    Although the serving types are now implemented as a bit mask, the
    values of 0, 1, and 2, specified by bit 0 and bit 1, retain their
    original meanings:

    o  0 - Do not serve any tapes (the default for earlier versions
           of OpenVMS).

    o  1 - Serve all available tapes.

    o  2 - Serve only locally attached (non-HSx and non-DSSI) tapes.

    If the TMSCP_LOAD system parameter is 0, TMSCP_SERVE_ALL is
    ignored.