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Dynamic File Allocation in COBOL

 
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Phantom
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PostPosted: Mon Jul 26, 2004 9:43 am    Post subject: Dynamic File Allocation in COBOL Reply with quote

I am using BPXWDYN to allocate a file in cobol dynamically. My question is - can the program be written generic to accept files with any LRECL as input ?

That is If I allocate a dataset (for use as input) using ALLOC command as shown below
Code:

'ALLOC DD(INFILE) DSN(''MY.PS.NAME'') SHR'.


then I should code a corresponding File Section entry like this right ?
Code:

FILE SECTION.                               
                                             
FD IN-PDS                                   
   RECORDING MODE IS F                       
   LABEL RECORDS ARE STANDARD               
   BLOCK CONTAINS 0 RECORDS                 
   DATA RECORD IS IN-REC.                   
                                             
01 IN-REC                      PIC X(80).   


I don't want to fix the file size as 80 Bytes. I want to accept files with any LRECL. Can this be accomplished in COBOL ?

Thanks a lot,
Phantom
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kolusu
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PostPosted: Mon Jul 26, 2004 10:01 am    Post subject: Reply with quote

Phantom,

COBOL is not yet there to handle dynamich LRECL Files. However there are other ways to achieve this functionality. If you are willing to change the file to variable block then you can read any LRECL datasets.

Code:

FD  IN-PDS                             
    RECORD IS VARYING FROM 1 TO 32760     
    DEPENDING ON ACTUAL-LENGTH.                 
01  IN-REC.                                   
    05  FILLER                  OCCURS 1 TO 32760
                       DEPENDING ON ACTUAL-LENGTH.
        10  FILLER              PIC X.



What exactly are you trying to do ?

Kolusu
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Phantom
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PostPosted: Tue Jul 27, 2004 8:13 am    Post subject: Reply with quote

Thanks a lot kolusu,

Code:

What exactly are you trying to do ?


Nothing much. I was just trying to explore the features of BPXWDYN (Thanks for the documentation that you provided). If I can dynamically allocate different files using BPXWDYN, I thought it should also support dynamic LRECLs. Just out of curiosity.!!!

What I was thinking was, if I can allocate a DDNAME in procedure-division then there should be some way to override the FILE-SECTION entry too....(dynamically).

Thanks,
Phantom
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jimmy_augustine
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PostPosted: Fri Aug 27, 2004 8:46 am    Post subject: Reply with quote

Phantom,
This is a wonderful peace of information i was looking for!!. Could you please explanin me how do you do that dynamic file allocation on the fly in a COBOL program?
Thanks
Jimmy
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kolusu
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PostPosted: Fri Aug 27, 2004 9:05 am    Post subject: Reply with quote

Jimmy,

Please search before posting. There are several examples showing dynamic allocation using BPXWDYN.

Check this link

http://www.mvsforums.com/helpboards/viewtopic.php?t=1905&highlight=bpxwdyn

Hope this helps...

Cheers

kolusu
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Jmoorthy
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PostPosted: Thu Aug 23, 2007 11:35 pm    Post subject: Reply with quote

Hi,
Is any one can help give a code of this module (BPXWDYN )and same for allocation and deallocation of datasets. I dont have facility to call The modulle in mainframe .

Thanks in advance
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Jmoorthy
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PostPosted: Fri Aug 24, 2007 4:39 am    Post subject: Reply with quote

How to allocate a dynamic tape dataset ?
Please advise in this regard
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kolusu
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PostPosted: Fri Aug 24, 2007 7:09 am    Post subject: Reply with quote

Jmoorthy wrote:
How to allocate a dynamic tape dataset ?
Please advise in this regard


Jmoorthy,

You canNOT allocate a dynamic tape dataset.

Kolusu
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Jmoorthy
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PostPosted: Wed Aug 29, 2007 11:58 pm    Post subject: Reply with quote

Thank you ,

Please suggest me how to deallocate a dataset. I have tried with delete or Removing the catolog in that sequence .But my requirment is only deallocate a particular dataset.
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Jmoorthy
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PostPosted: Thu Aug 30, 2007 12:11 am    Post subject: Reply with quote

The above query is for dynamic deallocation .
Also I can allocate only dynamic Disk DATSET , Please suggest in anyother High level assembler language its possible to dynamic allocate or deallocate all type of datset.Please advise in this regard.
Actually my requirment is I want to allocate or deallocate a dynamic datset with high level assembler .I will this as a routine in calling program .Calling program
should give input that for its allocate or deallocate .If allocate ddname and dsnname and status . If status is new user has to mention UNIT,VOLUME,RECFM,LREC,EXPDTall the inputs,Id its a SHR or OLD no problem.
After getting thes inputs from user This above routine will allocate a dataset.
llly , For deallocation get ddname and dsnname .once received deallcoate a dataset
buT For deallocation how to deallocate ,I am not sure about deallocation
Please advise in this regard , Whether this way is correct.
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jim haire
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PostPosted: Tue Nov 23, 2021 12:33 pm    Post subject: Reply with quote

Kolusu,
I saw you posted back in 2007 that you cannot dynamically allocate a tape dataset. I am wondering if the capability is available for allocating a virtual tape dataset?

I have tried BPXWDYN. I also tried writing ALLOC lines to a dataset that IDCAMS could process. I don't know if I have these formatted incorrectly or it just isn't possible.

My scenario is that I am reading in a dataset which contains the names of a input file and an output file. I read in a record and try to allocate the output dataset like the input dataset, except I want to allocate the output dataset as a VTS, because the file is very large.

I then write a REPRO line to copy the input dataset to the output dataset.
It appears that the only part that does not work is the allocation of the tape dataset. I have used the UNIT() and the RETPD() parameters. I don't want to use the VOLUME() parameter as I don't know the volume number to use. Is there a different parameter I could use?

Thanks for your help!
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kolusu
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PostPosted: Tue Nov 23, 2021 3:40 pm    Post subject: Reply with quote

jim haire wrote:
Kolusu,
I saw you posted back in 2007 that you cannot dynamically allocate a tape dataset. I am wondering if the capability is available for allocating a virtual tape dataset?

I have tried BPXWDYN. I also tried writing ALLOC lines to a dataset that IDCAMS could process. I don't know if I have these formatted incorrectly or it just isn't possible.


Jim,

You can allocate a tape dataset now with BPXWDYN. You need to provide the parm MOUNT. Check this Link for the documentation of BPXWDYN

jim haire wrote:

My scenario is that I am reading in a dataset which contains the names of a input file and an output file. I read in a record and try to allocate the output dataset like the input dataset, except I want to allocate the output dataset as a VTS, because the file is very large.


You can use DFSORT to read the input file and dynamically generate the JCL which will be submitted via INTRDR to copy where you can provide all the parameters to Output datasets. Let me know if you are interested in doing that.
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haatvedt
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PostPosted: Fri Dec 31, 2021 1:52 am    Post subject: Reply with quote

Jim / Kolusu,

years ago I used BPXWDYN to dynamically allocate a tape dataset. However I had to request a security change to allow my userid to dynamically mount tapes.

perhaps this has changed, however you may want to check with you system programmers / security folks.
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