Activating and deactivating IOPT

IOPT_SET_ON activates or deactivates IOPT. The current setting can also be queried.

IOPT_SET_ON                                                                                                                                         

IOPT_SET_ON=YES

IOPT_SET_ON=NO

IOPT_SET_ON=CHK

IOPT_SET_ON?

YES	IOPT is activated on the system. In VM mode this setting is required on all systems on which IOPT is to be active.
NO	IOPT is deactivated on the system. In VM mode this setting is required on all systems on which IOPT is to be deactivated.
CHK	IOPT runs in check mode, i.e. IOPT does not intervene in I/O handling, but it is possible to ascertain which interventions IOPT would perform if it were activated. This enables you to check whether the use of IOPT makes sense, see the section“Check mode”.
?	The current setting is queried.