Using the IEFSSNxx Parmlib Member

Both the positional and the keyword format IEFSSNxx parmlib member allow the installation to specify the following information about a subsystem:

The subsystem name
The subsystem initialization routine
The parameters to be passed to the initialization routine
For the primary subsystem, whether it should be automatically started during master scheduler initialization

Use the keyword format IEFSSNxx parmlib member to dynamically add a subsystem, which allows you to specify the following additional information about a subsystem during subsystem definition processing:

The console to which messages issued by the SSI will be directed.
The console to which messages issued by the subsystem initialization routine will be directed.

Note: The ability to run in parallel is only in the keyword format of the IEFSSNxx parmlib member.

The installation or subsystem can use the CONSNAME parameter of an IEFSSNxx parmlib entry to specify a console name. The SSI does not verify that the named console is defined or active. If you specify a console name that is not valid, the standard write-to-operator processing occurs. If you do not specify a console name, messages are directed to the master console.

The console name is passed to the subsystem initialization routine in the parameter list mapped by IEFJSIPL. The initialization routine can use the console name when issuing messages.

Specifying a console name is important only during subsystem initialization. After subsystem initialization, SSI messages are issued in response only to dynamic SSI commands; such as, SETSSI and DISPLAY SSI. These messages are issued to the console from which the command was issued, or in the case of the DISPLAY SSI command, to the specified console, if any.

See z/OS MVS Initialization and Tuning Reference for the syntax of the keyword format IEFSSNxx parmlib member.