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Mukunda
Beginner
Joined: 11 Dec 2002
Posts: 46
Topics: 15
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 Posted: Thu Jul 31, 2003 3:52 pm Post subject: Maximum limit of DDs associated with COBOL program |
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Is there any limit on number of SELECT ASSIGN statements in a COBOL program? I need to read some 90 transaction files and validate them? Call all that be done in a single program?  |
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slade
Intermediate
Joined: 07 Feb 2003
Posts: 266
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Location: Edison, NJ USA
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slade
Intermediate
Joined: 07 Feb 2003
Posts: 266
Topics: 1
Location: Edison, NJ USA
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| Posted: Thu Jul 31, 2003 4:41 pm Post subject: |
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P.S.
You should also check the JCL limit on DD stmts. I think it's 256, but I'm not sure.
Regards, Jack. |
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kolusu
Site Admin
Joined: 26 Nov 2002
Posts: 12380
Topics: 75
Location: San Jose
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| Posted: Thu Jul 31, 2003 4:44 pm Post subject: |
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mukunda,
The latest Enterprise COBOL programs can handle a maximum of 65,535 file names to the select file-name clause.
So check this link for Compiler limits
Hope this helps....
cheers
kolusu |
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kolusu
Site Admin
Joined: 26 Nov 2002
Posts: 12380
Topics: 75
Location: San Jose
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| Posted: Thu Jul 31, 2003 5:52 pm Post subject: |
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Slade,
The maximum number of DD statements per job step is 3273, based on the number of single DD statements allowed for a TIOT (task input output table) control block size of 64K. This limit can be different depending on the installation-defined TIOT size.The IBM-supplied default TIOT size is 32K.
Kolusu |
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Mukunda
Beginner
Joined: 11 Dec 2002
Posts: 46
Topics: 15
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| Posted: Fri Aug 01, 2003 8:15 am Post subject: |
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Slade & Kolusu
Thank you very much  |
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prnair
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Joined: 18 Jul 2004
Posts: 2
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| Posted: Thu Sep 15, 2005 11:40 am Post subject: |
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Kolusu,
Could you please let me know the maximum number of DD Statements possible when the TIOT size is 32K? I believe it is not (3273/2) ~ 1636, because one of our jobs is abending with around 500 datasets.
Regards,
Pradeep. |
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kolusu
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Location: San Jose
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prnair
Beginner
Joined: 18 Jul 2004
Posts: 2
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| Posted: Fri Sep 16, 2005 11:07 am Post subject: |
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Kolusu,
Thank you for providing the relation between the TIOT size and the maximum number of DD's allowed. The problem with our job was that each dataset was requesting 20 units. The job ran successfully when this was removed.
Could you please post the link to the manual in which shows the relationship between the TIOT and the number of DD units?
Thank you,
Pradeep. |
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kolusu
Site Admin
Joined: 26 Nov 2002
Posts: 12380
Topics: 75
Location: San Jose
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| Posted: Fri Sep 16, 2005 3:53 pm Post subject: |
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Could you please post the link to the manual in which shows the relationship between the TIOT and the number of DD units?
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Hmm the last column in the other link did show the relationship between the TIOT and the number of DD units?
Use the following to calculate the maximum number of DDs allowed per Job Step:
The TIOT Prefix, Header, and Trailer consume sixty (60) ('3C'x) bytes of the total TIOT space available to a Job Step. A DD statement requesting a single(1) unit requires twenty (20) bytes ('14'x) of TIOT space. Twenty bytes for the basic information for the first unit and an additional four bytes for the second unit and so on. In your case it requires 156(60+20+(4*19)=156) bytes for every DD as each is requesting 20 units.
You can the same information can be found in MVS Initialization and Tuning Reference (Document Number: SA22-7592-11)
http://publibz.boulder.ibm.com/cgi-bin/bookmgr_OS390/BOOKS/iea2e260/4.6?DT=20050715035016
Hope this helps...
Cheers
Kolusu
_________________
Kolusu
www.linkedin.com/in/kolusu |
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