Started task processing

When you start a started task, the system determines whether the START command refers to a procedure or a job. (The system validates that the IEFJOBS DD exists within the MSTJCLxx member.) If the IEFJOBS DD exists, the system searches the IEFJOBS DD concatenation for the member requested in the START command. If there is no member by that name in the IEFJOBS concatenation, or if the IEFJOBS concatenation does not exist, the system searches the IEFPDSI DD for the member requested in the START command.

If a member is found, the system examines the first record for a valid JOB statement and, if one exists, uses the member as the JCL source for the started task.

If the member does not have a valid JOB statement in its first record, the system assumes that the source JCL is a procedure and creates JCL to invoke the procedure. After JCL source has been created (or found), the system processes the JCL.