Setting up started tasks with the Master JCL
The source JCL for a started task can be a job (source JCL that begins with a JOB statement) or a cataloged procedure. See z/OS MVS JCL Reference for information that describes the advantages of using one form of source JCL over another (using a job rather than a procedure).
If the source JCL for a started task is a job, the member containing the JCL must be part of a data set in the IEFPDSI DD or the IEFJOBS DD concatenation of MSTJCLxx. (If the member is not part of a data set in the IEFPDSI or IEFJOBS concatenation of MSTJCLxx, the procedures that act as source JCL for other started tasks will not be found.) IBM® suggests that you define a new data set in MSTJCLxx (pointed to by the IEFJOBS DD statement) that will contain the tailored JCL to support started tasks.
To create source JCL that is a job (with, for example, JOB, JES2 JECL, and OUTPUT statements) for a started task, you must first decide whether these jobs should be mixed with procedures (part of the IEFPDSI concatenation) or placed into a separate data set (part of the IEFJOBS concatenation) containing only jobs.