Adjust CON= system parameter to accommodate default change

Description: Before z/OS V1R13, the default console operating mode was SHARED. Beginning with z/OS V1R13, the default console operating mode has changed from SHARED mode to DISTRIBUTED mode. The release of z/OS following z/OS V2R1 is planned to be the last release in which the consoles component will support SHARED mode. IBM recommends that you migrate to DISTRIBUTED mode, which was introduced in z/OS V1.10.

Element or feature:

BCP.

When change was introduced:

z/OS V1R13.

Applies to migration from:

z/OS V1R12.

Timing:

Before the first IPL of z/OS V2R1.

Is the migration action required?

Yes, if there is no specification on the CON= system parameter and SHARED mode is required.

Target system hardware requirements:

None.

Target system software requirements:

None.

Other system (coexistence or fallback) requirements:

None.

Restrictions:

None.

System impacts:

Impacts could be experienced falling back to shared, but only after taking advantage of some of the functionality offered in distributed. For more information, see "Operation modes of console support" in z/OS MVS Planning: Operations.

Related IBM Health Checker for z/OS check:

Use check ZOSMIGV1R13_CNZ_CONS_OPER_MODE, available with APAR OA32930, to determine if your installation has explicitly identified your console service operating mode.

Steps to take: Examine the system parameters used to IPL the system or sysplex. The initial mode is specified on the CON= system parameter. Use the D OPDATA,MODE to find the current mode, which is displayed in message CNZ9006I.

If DISTRIBUTED is specified, no action is required.
If SHARED is specified, an action is not currently required, but DISTRIBUTED mode will become a required action in the future.
If there is no specification on the CON= system parameter, DISTRIBUTED mode is now the default in z/OS V1R13.
If there is no specification on the CON= system parameter and SHARED mode is required, you have to explicitly request the SHARED mode on the CON= system parameter. This allows the system or systems to continue functioning in the same manner as they do today. In the MULTISYSTEM sysplex environment, use the SETCON MODE=SHARED command to request SHARED mode.

Tip: When you activate the OPERCMDS class, you must have the CONTROL access authority to the profile MVS.SETCON.MODE when issuing the SETCON MODE command.

Reference information: For more information, see:

DOC APAR OA34738.
z/OS MVS Initialization and Tuning Reference.
z/OS MVS Planning: Operations.