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Difference between DSNs allocated using IEFBR14 & NWOMC


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Anuj Dhawan

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Joined: 22 Apr 2006
Posts: 6250
Location: Mumbai, India

PostPosted: Fri Sep 14, 2007 6:59 pm
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Hi,

What is the difference between DSNs allocated using IEFBR14 & NWOMC ?

By difference I mean, when some COBOL program will try to READ an DSN created using IEFBR14, it may abend if that DSN is never written to but this is not the case with NWOMC located DSNs, why so?


P.S.: I think, I don't know whether I put a right question or not and perhaps, may be that's why I don't know the right answer. I've seen below type of steps in many JOBs at my site, I know the purpose but not the significance when I ask myself "what if IEFBR14 was used?"
Code:
//STEP010  EXEC PGM=NWOMC,                         
//             REGION=5120K                         
//STEPLIB  DD  DSN=&HLQ..PROD.PGMLIB,               
//             DISP=SHR                             
//DD01     DD  DSN=&STAT.EP.EP622.SEDUE.RPT&NWIDE, 
//             DISP=(,CATLG,DELETE),               
//             DSORG=PS,                           
//             RECFM=VB,                           
//             LRECL=883,                           
//             BLKSIZE=0,                           
//             DATACLAS=STANDARD,                   
//             UNIT=&SYSDA                         
//DD02     DD  DSN=&STAT.EP.EP663.SCOUTEFF&NWIDE
.
.
.


and so this thread comes up.
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dick scherrer

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Joined: 23 Nov 2006
Posts: 19244
Location: Inside the Matrix

PostPosted: Fri Sep 14, 2007 7:29 pm
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Hi Anuj,

Who wrote/maintains NWOMC? It is not an IBM utility.

If your dataset is not sms-managed and you allocated it using IEFBR14, no end-of-file is written which can cause programs to run incorrectly or abend.

If your data set is allocated and has only an EOF, your program will reach AT END on the first read and the abend will be avoided.

If your dataset is sms-managed, the problem goes away.
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Anuj Dhawan

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Joined: 22 Apr 2006
Posts: 6250
Location: Mumbai, India

PostPosted: Fri Sep 14, 2007 8:02 pm
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dick scherrer wrote:
Who wrote/maintains NWOMC? It is not an IBM utility.

I was under the impression that this is an IBM utility & is in use across the shops. Actually, I checked in Source Base Library of my shop, this program was not there, so I thought it's a utility from the IBM side which invokes from the system libraries at run time.

Thanks for the clarification Dick, now I've different approach to look for the same query. By the way, how do we know that particular utility, such as imagined by me, is not from IBM utility list, any link ?
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dick scherrer

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Joined: 23 Nov 2006
Posts: 19244
Location: Inside the Matrix

PostPosted: Fri Sep 14, 2007 8:25 pm
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Hi Anuj,

Many of the IBM utilities are named IExxxxxx (IEBGENER, IEFBR14, IEHLIST, ETC). There are also ICExxxx, SORT, IDCAMS, etc.

I know of no list that names every IBM utility.

NWOMC might be an alias of some other module. . . Find the executable, browse it, and look for an eye-catcher that may give a clue as to who wrote it. Might it be part of FileAid? Is NWOMC in the steplib you point to or is it found in the link list?
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Anuj Dhawan

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Joined: 22 Apr 2006
Posts: 6250
Location: Mumbai, India

PostPosted: Mon Sep 17, 2007 6:34 pm
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Hi Dick,

Thanks for the suggestion.

NWOMC is not an alias of some other module. It's executable module is available in load library, so we point NWOMC in the steplib.

Still, I'm not able to find out something intelligent yet icon_mad.gif , Will let you know once I got something good. icon_smile.gif
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dick scherrer

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Joined: 23 Nov 2006
Posts: 19244
Location: Inside the Matrix

PostPosted: Mon Sep 17, 2007 7:25 pm
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Hi Anuj,

Is the executable in one of "your" loadlibs or is it in a "system" lib?

Were you able to look at the executable in hex and learn anything?

Is there someone who has been on the system for a long time that might know? The storage admin folks might know of this module.
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