The OPEN options are OPEN IS AUTOMATIC and OPEN IS MANUAL.
    These options determine whether any user can open a previously
    unopened or a closed database by simply invoking it and executing
    a DML statement (OPEN IS AUTOMATIC, the default). When OPEN IS
    MANUAL is specified, only users with sufficient Oracle Rdb privilege
    (ADMINISTRATOR privilege) for the database can enter an RMU/OPEN
    command to open the database.

    When you use the SQL ALTER DATABASE or RDO CHANGE DATABASE
    OPEN IS MANUAL option in conjunction with the RMU/OPEN
    /ACCESS=RESTRICTED command, access to the database is limited
    to users with SQL DBADM or RDO ADMINISTRATOR privilege for
    the database or OpenVMS BYPASS or SYSPRV privilege so that
    maintenance (if the RMU image was not installed with the OpenVMS
    SYSPRV privilege) operations can proceed without interference
    from other users.