IOS_MIDAW

Description:

This check verifies that the modified indirect addressing word (MIDAW) facility is enabled. MIDAWs are a more efficient way to issue I/O commands.

Reason for check:

MIDAW is a extension to I/O that allows better use of I/O bandwidth.

You can verify whether the MIDAW facility is enabled using the following console command:

DISPLAY IOS,MIDAW

In response to this command, the system issues message IOS097I to display whether MIDAW is active:

IOS097I 12.27.47 MIDAW FACILITY 279     
MIDAW FACILITY IS ENABLED

To change MIDAW enablement, see the SETIOS command in z/OS MVS System Commands.

z/OS® releases the check applies to:

z/OS V1R12 and later.

Parameters accepted:

Yes, the following parameters are accepted:

PARM(‘MIDAW(state)')

Since, there may be a rare instance when MIDAW should not be enabled, you can set the expected state of MIDAW enablement the check expects to either:

PARM('MIDAW(YES)'), which is the default, indicates that the expected state the check expects is MIDAW enabled.
PARM('MIDAW(NO)') indicates that the state expected by the check is MIDAW disabled.

User override of IBM® values:

The following shows the default keywords for the check, which you can override on either a POLICY statement in the HZSPRMxx parmlib member or on a MODIFY command. This statement may be copied and modified to override the check defaults:

 UPDATE
     CHECK(IBMIOS,IOS_MIDAW)
     INACTIVE
     SEVERITY(LOW) INTERVAL(ONETIME) DATE('date_of_the_change')
     REASON('Your reason for making the update.')

Debug support:

No.

Verbose support:

No.

Reference:

For more information, see information on the SETIOS command in z/OS MVS System Commands.

Messages:

This check issues the following exception messages:

IOSHC105E

See IOSHC messages in z/OS MVS System Messages, Vol 9 (IGF-IWM).

SECLABEL recommended for MLS users:

SYSLOW