Initializing the kernel using a cataloged procedure

A cataloged procedure is a set of job control statements that are stored in a system library (for example SYS1.PROCLIB). The storage location for cataloged procedures is installation-defined. For z/OS® UNIX, the STARTUP_PROC statement in the BPXPRMxx member of SYS1.PARMLIB specifies a cataloged procedure that initializes the kernel. The default name is OMVS.

Following is the IBM-supplied cataloged procedure in SYS1.PROCLIB:

//OMVS PROC
//OMVS EXEC   PGM=BPXINIT,REGION=0K,TIME=NOLIMIT

In the EXEC statement in the procedure, the PGM parameter identifies the name of the initialization module. The REGION=0K parameter specifies that the kernel is to use all of the available private area storage within the kernel address space. The TIME=NOLIMIT parameter specifies that kernel is to have unlimited processor time.

Though not recommended, you can replace the OMVS procedure with a procedure that has a different name. If you use a started procedure other than OMVS,

The replacement started procedure must also be a single job step procedure that invokes the BPXINIT program (EXEC PGM=BPXINIT). If it invokes any other program, OMVS initialization will fail.
You must change the procedure name in the RACF® started procedures table or change the definition in the STARTED Class. See Steps for preparing RACF.

Started subtasks such as OMVS, BPXOINIT, and colony address spaces fall under SUBSYS STC. These address spaces might be subject to IEFUSI limitations if IEFUSI exits are allowed for SUBSYS STC. IBM® strongly recommends that you always set REGION=0 and MEMLIMIT=NOLIMIT for OMVS, BPXOINIT, and colony address spaces.