DD without DSN name in IEFBR14 Job

padma_prakasam · New User Joined: 06 Oct 2005 Posts: 31

Hi,

I have a step running IEFBR14 like below,

//UPDS1 EXEC PGM=IEFBR14
//BKPVSN DD DISP=(,PASS,DELETE),
// UNIT=(CO3490,,DEFER),VOL=(,RETAIN,,1),
// DCB=BLKSIZE=32640,
// LABEL=(1,SL,,,RETPD=30)
//*

I 'm not sure the purpose of this step. I'm referring this in VOL parameter in other steps like this VOL=(,RETAIN,,REF=*.UPDS1.BKPVSN),
Can anyone explain this step usage??

expat · Posted: Sat Apr 07, 2007 12:10 pm

Some tape management software products operate on the principal that the first dataset on a multi label tape acts as a control dataset. When that dataset expires, the tape may be scratched.

Shobana Bhaskar · Posted: Mon Apr 09, 2007 11:58 am

Hi padma,

The UPDS1 step defines the property of a dataset.
VOL - This refers to the volume on which the dataset resides.

VOL=(,RETAIN,,REF=*.UPDS1.BKPVSN) - This refers to the DD BKPVSN in step UPDS1 so that the VOL mentioned in that DD would be used for this dataset.

agkshirsagar · Posted: Mon Apr 09, 2007 4:31 pm

I am still not clear what will be the o/p if this JOB is executed as is?

dick scherrer · Posted: Tue Apr 10, 2007 12:57 am

Hello,

There won't be any o/p. This jcl is to allocate a unit for later processing (in subsequent steps).

reddy260 · New User Joined: 28 Feb 2007 Posts: 2 Location: india

pls drop some more details regarding this. waiting for detailed explanation

thanks
Yugandhar

expat · Posted: Tue Apr 10, 2007 1:24 pm

reddy260 · New User Joined: 28 Feb 2007 Posts: 2 Location: india

//BKPVSN DD DISP=(,PASS,DELETE),

in this some one is telling it is referring to new data set..

How it comes

expat · Posted: Tue Apr 10, 2007 2:53 pm

Because, if you read the JCL manual, it will tell you that if you omit the first parameter of the DISP field, the default will be NEW.

It is not referring to a new dataset, it is creating a new dataset. With the use of the JCL shown by the OP, subsequent datasets are written to the same tape using the referback of *.stepname.ddname

As i said above, this is used to create a dummy dataset which is used by the tape management software to control the expiry of a tape. The fact that it uses a system generated dataset is neither here nor there, the RETPD=30 will keep that tape for 30 days, unless the TMS rules are set up differently.

Of course TMM would be a far better method than using multi label tapes.