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Differences between Sequential File (SE) and GDG file

 
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pnkumar
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PostPosted: Fri Jul 17, 2009 12:41 pm    Post subject: Differences between Sequential File (SE) and GDG file
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Hi,

When I ran the program with the output data set as GDG file, got the null values, but the same case is not happening with the SE file which contains spaces instead of nulls.

please clarify me why it is happening like this?

Thanks
Kumar
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expat

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PostPosted: Fri Jul 17, 2009 12:54 pm    Post subject:
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There should be no difference, a GDS is a sequential file, just happens to be associated with a GDG base.

Any difference in the file attributes ? FB VB ?

What is the difference between null values and spaces. Are you browsing bot files or browse one and edit/view another ?
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pnkumar
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PostPosted: Fri Jul 17, 2009 2:54 pm    Post subject: Reply to: Differences between Sequential File (SE) and GDG f
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Hi Expat,

File attributes are same and the file is FB. Both files are opened in Browse mode only. Nulls represent with X'00' where as space with X'40'. We can see this difference in a file data by using the HEX ON.

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Kumar
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priyesh.agrawal

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PostPosted: Fri Jul 17, 2009 11:50 pm    Post subject:
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Should not matter to the program if it is a sequential dataset or a GDG dataset, as long as file attributes are same.

If you are confident that the only change in JCL is the dataset name, then put a display in the program to see what exactly it is writing and then run the program for both the cases to see if there is any difference (which should not be, why it would be icon_rolleyes.gif )
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Thangaprabhu

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PostPosted: Mon Jul 20, 2009 4:25 pm    Post subject:
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Hi,

Check the Definition of your GDG base and Sequential file both should be the same.
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Anuj Dhawan

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PostPosted: Mon Jul 20, 2009 5:21 pm    Post subject:
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Thangaprabhu wrote:
Check the Definition of your GDG base and Sequential file both should be the same.
To start with, "GDG base" does not come with a definition but even if that's there, it should not be a reason for what is asked.

As Priyesh has said, there should not be any difference.Suggest, you show us the JCL you execute, SYSOUT from both the jobs and contents of the file & GDG in HEX ON mode.
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kalhor

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PostPosted: Tue Jul 21, 2009 7:18 pm    Post subject:
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Hi,
When you are using generation data group (GDG), you must defined a base for the first time for it, in your definition you are determine that the maximum size, maximum number of the data sets which can be saved and the other attributes. after that definition completed you can use it in your batch and the data set will be created as you have defined.
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expat

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PostPosted: Tue Jul 21, 2009 7:40 pm    Post subject:
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kalhor wrote:
Hi,
in your definition you are determine that the maximum size, maximum number of the data sets which can be saved and the other attributes.

Please clarify exactly what other attributes that can be specified, giving an example of the code used.
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Thangaprabhu

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PostPosted: Tue Jul 21, 2009 7:41 pm    Post subject:
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Nope...For the first while creating GDG base we have to specify the no of versions a GDG can hold. After creating GDG base the versions of it can be different of definitions. Check the attributes of the current version of GDG base with the sequential file. I think there will be a mismatch of it.
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expat

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PostPosted: Tue Jul 21, 2009 7:46 pm    Post subject:
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Thangaprabhu wrote:
Nope...For the first while creating GDG base we have to specify the no of versions a GDG can hold. After creating GDG base the versions of it can be different of definitions. Check the attributes of the current version of GDG base with the sequential file. I think there will be a mismatch of it.

/RANT ON
The use of terminology is totally incorrect. Using the correct terminolgy is IMPORTANT.

Versions and generations are two valid terms when discussing a GDS, both with totally different meanings. The number of versions never deviates from 1. There can only ever be ONE version of a GDS. However, there can me multiple generations
/RANT OFF

Quote:
Check the attributes of the current version of GDG base with the sequential file. I think there will be a mismatch of it.

Please explain exactly what you think you mean, and also give examples of the attributes to check.
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Thangaprabhu

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PostPosted: Tue Jul 21, 2009 8:44 pm    Post subject:
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Hi Expat,

For eg:- I have created a GDG base SAMPLE.GDG with a limit of 250. Then i can create 250 versions of SAMPLE.GDG it. And all the 250 versions need not be of same definiitions.


//INFILE DD DSN=SAMPLE.GDG(+1),
// DISP=(NEW,CATLG,DELETE),
// UNIT=SYSDA,
// SPACE=(CYL,(200,50),RLSE),
// DCB=(LRECL=36,RECFM=FB)

After execution of this step a version of SAMPLE.GDG will get created

//INFILE DD DSN=SAMPLE.GDG(+1),
// DISP=(NEW,CATLG,DELETE),
// UNIT=SYSDA,
// SPACE=(CYL,(100,10),RLSE),
// DCB=(LRECL=1000,RECFM=FB)


After execution of this step in a different job an another version of SAMPLE.GDG will get created

so all the versions of can be of different definitions.

Please correct me if i am wrong.
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Craq Giegerich

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PostPosted: Tue Jul 21, 2009 8:47 pm    Post subject:
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VERSIONS AND GENERATIONS ARE DIFFERENT THINGS!
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expat

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PostPosted: Tue Jul 21, 2009 10:41 pm    Post subject:
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Thangaprabhu wrote:
Hi Expat,

For eg:- I have created a GDG base SAMPLE.GDG with a limit of 250. Then i can create 250 versions of SAMPLE.GDG it. And all the 250 versions need not be of same definiitions.

Please correct me if i am wrong.

YOU ARE WRONG
Please re-read my post, especially the part between the RANT ON and RANT OFF
Then take a look at the c**p you have replied with. I have stated - from proven experiment that there is NEVER more than one version of a GDS in existence.

When you use the wrong terminology it only confuses matters for others trying to help, and also makes YOU look unprofessional.

Please learn and then use the correct terminology.
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Anuj Dhawan

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PostPosted: Wed Jul 22, 2009 9:00 pm    Post subject:
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Quote:
Then i can create 250 versions of SAMPLE.GDG
You can (also) catalog a generation using either absolute or relative numbers. When a generation is cataloged, a generation and version number is placed as a low-level entry in the GDG. To catalog a version number other than V00, you must use an absolute generation and version number. Full stop.
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