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A few tings here. The first three letters of the PGM= (IEF) in this case,
refer to the section of the system that it belongs to. I can't remember all
the 3-letter codes, but things line IEF where "data management", "IEH"
utilities, etc. The same is true of the error messages. So, an IEF....
message was from data management, etc. The "I" means IBM and the next two
letters are the subsystem. Later on the I=IBM kid of went away and now the
first 3 just represent the subsystem/application.
As in aside, the last letter means something to. For example in IEF450I the
final "I" means information.
Some of the other letters are
A Action is required
D Decision (usually from a WTOR macro)
E Error
I Information
T Termination
W Wait state
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So, why does IEFBR14 exist?
The design of MVT and MVS sometimes requires that dataset allocation be run.
For example, you may notice that if you VARY OFFLINE a device nothings
happens for a while. That "while" is when data management is next invoked by
a job (or STC or TSO) starting. So, for the convenience of the system
operator IEFBR14 is supplied.
The way this works is as follows:
Create a member in SYS1.PROCLIB(A) that contains just one line of JCL:
//IEFRDER EXEC PGM=IEFBR14,REGION=2K
Then when operator would issue "VARY dev,OFFLINE" and then an "S A" command
at the MVS console. The result is that a "job (STC really)" is run (IEFBR14)
that takes uses resources and then the device is knocked offline without
having to wait for a real job to execute. This is why its named IEF br14.
--
Sent from: http://hercules390.996247.n3.nabble.com/Hercules390-Mvs-f24981.html