Initializing Your Subsystem

If you are defining your own subsystem, you can code an initialization routine and have control pass to that routine by specifying the name of the initialization routine when you define your subsystem. You can define parameters to be passed to your initialization routine.

The initialization routine is linked to in supervisor state and key zero. On entry to the routine, there are no locks held and register 1 points to a two-word parameter list:

Word: Contents
One: Address of the SSCVT (mapped by the IEFJSCVT macro).
Two: Address of the subsystem initialization parameter list (JSIPL, mapped by IEFJSIPL). See z/OS® MVS™ Data Areas in the z/OS Internet library (http://www.ibm.com/systems/z/os/zos/bkserv/) for the format of JSIPL.

Figure 1 shows the input to the initialization routine when your initialization routine gets control from the system.

Figure 1. Input to the Initialization Routine