IEFBR14 is an IBM mainframe utility program. It runs in all IBM mainframe environments derived from OS/, including z/OS. It is a placeholder that returns the. JCL & VSAM: Hi, Can we use IEFBR14 utility to create Partitioned U may use any utility for creating PS/, idcams, iehprogm etc. IEFBR14 is an IBM utility better known for being a dummy utility because it does almost nothing. IEFBR14 performs no other action than return a.
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It is a placeholder that returns the exit status zero, similar to the true command on UNIX-like systems.
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. A secondary reason to run IEFBR14 was to unmount devices usually tapes or disks that had been left mounted from a previous job, perhaps because of an error in that job’s JCL or because the job ended in error.
In either event, the system operators would often need to demount the devices, and a started task — DEALLOC — was often provided for this purpose.
IEFBR14 – Wikipedia
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. The “IEF” derives from iefbbr14 convention on mainframe computers that programs supplied by IBM were grouped together by function or creator and that each group shared a three-letter prefix.
As explained below, “BR 14” was the utilitj function utilit 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 ” B ranch to the address in R egister 14 “, which by convention is used to “return from a subroutine “. Example JCL would be:. BR is a pseudo instruction for BCR But, initially IEFBR14 was not coded with these characteristics in mind, as IEFBR14 was initially used as a dummy control section, one which simply returned to the caller, not as an executable module.
The original version of the program did not alter register 15 at all as its original application was as a placeholder in certain load modules ifebr14 were generated during Sysgen system generationnot as an executable program, per se.
IBM Mainframes: IEFBR14 Utility
Later, a second instruction was to be added to clear the return code so that it would exit with a determinant status, namely zero. Initially, programmers were not using all properties of the Job Control Language, anyway, so an indeterminate return code was not a problem.
However, subsequently programmers were indeed using these properties, so a determinate status became mandatory. From Wikipedia, the free encyclopedia. Retrieved from ” https: IBM mainframe operating systems.