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hchinnam · Beginner Joined: 04 Feb 2005 Posts: 31 Topics: 10

ALL,

Please look at the DD statement below

expat · Posted: Mon Sep 15, 2008 5:44 am Post subject:

What does the message say in the book

What is your GDG definition

And the correct term is generation not version. The two terms are completely different, please use the correct one !
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dbzTHEdinosauer · Posted: Mon Sep 15, 2008 7:30 am Post subject:

using disp=mod will only create a new generation if no generation exists.

Since a generation existed, the system went and found it.

using DISP=NEW would have created a new generation.

Attention to Detail!
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arvibala · Beginner Joined: 12 Feb 2008 Posts: 142 Topics: 67

Additional Info :
To refer to a newly created Generation in the same JCL we can use (+1)
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expat · Posted: Tue Sep 16, 2008 3:25 am Post subject:

hchinnam · Beginner Joined: 04 Feb 2005 Posts: 31 Topics: 10

hchinnam · Beginner Joined: 04 Feb 2005 Posts: 31 Topics: 10

expat · Posted: Tue Sep 16, 2008 9:03 am Post subject:

Yes, but you are using a different parameter in DISP aren't you.

I did ask you to provide info on the GDG base definition.
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jsharon1248 · Posted: Tue Sep 16, 2008 10:53 am Post subject:

I think I have the explanation. When you create the initial file with the DISP=(MOD,KEEP,KEEP), the dataset is in a deferred roll-in state. This term is briefly explained in Chapter 29, Processing Generation Data Groups in the DFSMS Using Datasets manual. If you check your allocation messages, you will not find the words 'ROLLED IN' with the IGD107I message. Also, a LISTCAT of the GDG base doesn't show the file. As long as the file is in this deferred roll-in state, the same file gets allocated every time you use the relative number +1. The game changes when you catalog the dataset. The file is rolled-in, and everything processes in the way we're all accustomed to.

I guess my question for the op would be, why do you want to do this? It looks like you just want to create a new generation. Why not just use the standard (NEW, CATLG,DELETE)? The interesting outcome I found was that even if you use DISP=(MOD,CATLG,DELETE) for the file in the deferred roll-in state, the data is writting over the same as if you used DISP=(NEW,CATLG,DELETE).

hchinnam · Beginner Joined: 04 Feb 2005 Posts: 31 Topics: 10

hchinnam · Beginner Joined: 04 Feb 2005 Posts: 31 Topics: 10

hchinnam · Beginner Joined: 04 Feb 2005 Posts: 31 Topics: 10

hchinnam · Beginner Joined: 04 Feb 2005 Posts: 31 Topics: 10

All,

Thanks for your help. jsharon1248's post explains the issue.

jsharon1248 · Posted: Wed Sep 17, 2008 9:07 am Post subject:

If you want to append to the dataset, use DISP=(MOD,CATLG,DELETE) when you create the (+1). Then, use DISP=MOD and (+0) when you want to append (unless it's in the same job where you'd use the (+1)). There are a couple other ways to accomplish the same thing. You could code the specific generation, but that's not very flexible. The other option is to use a non-GDG dataset for all the MOD activity, and then copy that file to the GDG. This was an interesting topic.

kctechpro · Beginner Joined: 27 Aug 2008 Posts: 6 Topics: 1

Interesting! Shocked

I never realized you could use DISP=(MOD) with a GDG.
This behavior only works outside a scheduler, Right? Question

I thought most schedulers resolved the generations before execution and therefore would be looking for the (+1).