IEFBR14 was created because while DD statements can create or delete files easily, they cannot do so without a program to be run due to a certain peculiarity of the Job Management system, which always requires that the Initiator actually execute a program, even if that program is effectively a null statement. Thus a very simple do-nothing program was needed to fill that role. In either event, the system operators would often need to demount the devices, and a started task — DEALLOC — was often provided for this purpose. Also, all such started tasks must be a single jobstep as the "Started Task Control" STC module within the Job Management component of the operating system only accepts single-step jobs, and it fails all multi-step jobs, without exception. As explained below, "BR 14" was the essential function of the program, to simply return to the operating system. As explained further in "Usage" below, the name "BR14" comes from the IBM assembler-language instruction "Branch to the address in Register 14", which by convention is used to "return from a subroutine ".
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The real purpose is to allow the disposition of the DD statement to occur. Except for a few cases, lowercase alphabetic characters cannot be used in JCL. All jobs require JOB and EXEC statements, so this sample contains both: The JOB statement marks the beginning of a job, specifies the job name, and also might provide company-specific details or JCL parameters that apply to all job steps within the job.
The EXEC statement marks the beginning of a job step. Syntax rules for the name field are: The name must begin in column 3 of the JCL statement. The name can be one through eight characters in length. The remaining characters can be alphanumeric the letters A through Z and numbers 0 through 9 or special characters. Blank spaces cannot be included in a name. Aside from changing the step name, no further changes are required.
Only one subparameter value for job-end processing is specified, so the system will add an entry in the system or user catalog CATLG , whether the job step ends normally or abnormally. For an SMS-managed data set, override the space attributes specified through the default data class. If these are coded, the data set will be deleted but not uncataloged.
IEFBR14 should not be used to catalog or uncatalog tape data sets since to do so requires mounting the tape. In the JCL statements that appear in code examples, the lowercase text indicates items that you need to modify. As coded in this sample, the status subparameter value OLD tells the system that the data set already exists.
Both subparameter values for job-end processing DELETE are specified, so the system will delete the data set whether the job step ends normally or abnormally.
IEFBR14 JCL Utility Quick Reference