Portal | Manuals | References | Downloads | Info | Programs | JCLs | Master the Mainframes
IBM Mainframe Computers Forums Index
 
Register
 
IBM Mainframe Computers Forums Index Mainframe: Search IBM Mainframe Forum: FAQ Memberlist Usergroups Profile Log in to check your private messages Log in
 

 

Use of UNIT=AFF when merging large files on tape

 
Post new topic   Reply to topic    IBMMAINFRAMES.com Support Forums -> JCL & VSAM
View previous topic :: :: View next topic  
Author Message
Vivek Wilson

New User


Joined: 27 Nov 2008
Posts: 26
Location: India

PostPosted: Wed May 26, 2010 10:06 am    Post subject: Use of UNIT=AFF when merging large files on tape
Reply with quote

Hi,
I have a case wherein I'm required to Merge 60 exceptionally large files from Tape into another File, also on Tape. I understand I'll have to use UNIT=AFF=(Previous DD Name) to make sure that multiple tape mounts aren't attempted, but I also believe this would mean I would require to exclusively close each tape file. How exactly would I go about doing that? As of now, the code I'm using doesn't allow me to progress, giving an error as 'TMSS HAS DETECTED 59 TAPE UNITS FOR N******I. THIS NUMBER EXCEEDS STANDARDS. JOB, N******I HAS FAILED.' Please refer existing Code below:

Code:
//PS0010   EXEC PGM=IEBGENER                                     
//*DUMMYDD  DD UNIT=(TAPE,,DEFER)                                 
//SYSUT1   DD DSN=&HLQ..NDM.&TYPE..PART01,DISP=SHR               
//         DD DSN=&HLQ..NDM.&TYPE..PART02,DISP=SHR,UNIT=AFF=SYSUT1
//         DD DSN=&HLQ..NDM.&TYPE..PART03,DISP=SHR,UNIT=AFF=SYSUT1
etc upto 60 parts.
Code:
//SYSUT2   DD DSN=&HLQ..NDM.&TYPE(+1),     
//            DISP=(NEW,CATLG,DELETE),     
//*           UNIT=AFF=SYSUT1             
//            UNIT=CARTA00,VOL=(,,,99),   
//            EXPDT=99000                 
Any help would be much appreciated. Thanks.

Wilson...

P.S. The commented out lines have already been attempted & failed.
Back to top
View user's profile Send private message

enrico-sorichetti

Global Moderator


Joined: 14 Mar 2007
Posts: 10274
Location: italy

PostPosted: Wed May 26, 2010 10:13 am    Post subject: Reply to: Use of UNIT=AFF when merging large files on tape
Reply with quote

Quote:
but I also believe this would mean I would require to exclusively close each tape file.

please clarify ... EOF processing for concatenated datasets is automatic

Quote:
'TMSS HAS DETECTED 59 TAPE UNITS FOR N******I. THIS NUMBER EXCEEDS STANDARDS. JOB, N******I HAS FAILED.'

the message is clear ... nothing can be done here...
speak to Your support

the usual approach is ....
test with a couple of files to start with
if something fails with messages like the one You got...
it means that the process is not flawed in itself,
but it clashes with some limitations of the supporting software
Back to top
View user's profile Send private message
Vivek Wilson

New User


Joined: 27 Nov 2008
Posts: 26
Location: India

PostPosted: Wed May 26, 2010 10:39 am    Post subject:
Reply with quote

Quote:
please clarify ... EOF processing for concatenated datasets is automatic


If that's the case, then I was mistaken. Forget about this.

I will try out with a couple of files. If that doesn't work out, I can atleast try to find out what the actual limit is.

I Appreciate this Enrico. Muchos Gracias.
Back to top
View user's profile Send private message
gcicchet

Senior Member


Joined: 28 Jul 2006
Posts: 1703
Location: Australia

PostPosted: Wed May 26, 2010 2:42 pm    Post subject:
Reply with quote

Hi,

just be sure that when you invoke IEBGENER it actually uses the SORT program, you will see a huge difference in run time between IEBGENER and SORT.

Are you aware you cannot AFF DDNAME SYSUT2 to DDNAME SYSUT1.

SYSUT1 and SYSUT2 are both opened at the same time by the program and you cannot AFF to an already opened DDNAME.


Gerry
Back to top
View user's profile Send private message
dick scherrer

Site Director


Joined: 23 Nov 2006
Posts: 19270
Location: Inside the Matrix

PostPosted: Wed May 26, 2010 8:09 pm    Post subject:
Reply with quote

Hello,

Quote:
I will try out with a couple of files. If that doesn't work out, I can atleast try to find out what the actual limit is.
If this "doesn't work out", you need to determine why it didn't work and correct the problem. . . You should never spread 50 input files across 50 tape drives. Hopefully, if you tried, the job would be canceled immediately.

If you make sure the sort is used to copy the data, it will run far better than IEBGENER (unless IEBGENER automatically invokes the sort for copying files on your system) or IDCAMS. You may also improve the run time by specifying a high DCB=BUFNO=nn.
Back to top
View user's profile Send private message
Ronald Burr

Active User


Joined: 22 Oct 2009
Posts: 293
Location: U.S.A.

PostPosted: Wed May 26, 2010 8:19 pm    Post subject:
Reply with quote

To "ping pong" tape drives for concatenated input file(s) on 'n' physical drives, just specify UNIT=(TAPE,n) on the first DD statement.
Back to top
View user's profile Send private message
Vivek Wilson

New User


Joined: 27 Nov 2008
Posts: 26
Location: India

PostPosted: Thu May 27, 2010 8:22 am    Post subject:
Reply with quote

Quote:
To "ping pong" tape drives for concatenated input file(s) on 'n' physical drives, just specify UNIT=(TAPE,n) on the first DD statement.


Ping Pong? I didn't get that. Could you clarify Ronald?
Back to top
View user's profile Send private message
gcicchet

Senior Member


Joined: 28 Jul 2006
Posts: 1703
Location: Australia

PostPosted: Thu May 27, 2010 8:38 am    Post subject:
Reply with quote

Hi,

eg. by using UNIT=(TAPE,2)

If the dataset is a multi-volume one, it will mount the first volume to 1 tape drive and the second volume to another tape drive, so when the job has finished with the first volume, it will immediately start processing the second volume and rewind the first volume and then mount the third volume whilst the second volume is being processed and so on.

You should also use this for your output DD.


Gerry
Back to top
View user's profile Send private message
View previous topic :: :: View next topic  
Post new topic   Reply to topic    IBMMAINFRAMES.com Support Forums -> JCL & VSAM All times are GMT + 6 Hours
Page 1 of 1

 

Search our Forum:

Similar Topics
Topic Author Forum Replies Posted
No new posts UNIT=AFF for Easytrieve code gandikk JCL & VSAM 7 Wed Jul 12, 2017 11:42 pm
No new posts XML Parse for large file muralikrishnan_new COBOL Programming 3 Mon Jun 12, 2017 12:50 pm
No new posts getting three output files out of JOI... migusd SYNCSORT 7 Mon Jun 05, 2017 11:30 pm
No new posts Unable to create multiple files using... mbattu COBOL Programming 3 Fri May 05, 2017 5:35 pm
This topic is locked: you cannot edit posts or make replies. Merge two files and update Trailer re... Yashashri JCL & VSAM 1 Thu May 04, 2017 12:54 pm


Facebook
Back to Top
 
Mainframe Wiki | Forum Rules | Bookmarks | Subscriptions | FAQ | Tutorials | Contact Us