Defining mains

You must code a MAINPROC statement for every main in the JES3 complex. You may optionally code a DEVICE statement corresponding to some or all of your MAINPROC statements. The MAINPROC statement defines each main to JES3. The DEVICE statement, with DTYPE=SYSMAIN specified, defines the initial status of the main to JES3. If DTYPE= is not coded, the default is that the main is initially online to all mains. For a description of the parameters on these statements, see z/OS JES3 Initialization and Tuning Reference.

You are allowed to define a maximum of 32 mains in a single JES3 complex. Each main is defined on a separate MAINPROC statement. The name specified on the NAME parameter on the MAINPROC statement must match the MVS™ system name specified on the SYSNAME parameter in the IEASYSxx member of the MVS SYS1.PARMLIB data set.

For successful dynamic system interchange (DSI) processing, ensure that each processor containing a main that is eligible for DSI is properly defined.