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
 

 

CREATING NULL FILES using IEBGENER

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

New User


Joined: 23 Jan 2007
Posts: 16
Location: Mysore

PostPosted: Sun Nov 01, 2009 7:16 am    Post subject: CREATING NULL FILES using IEBGENER
Reply with quote

Hi,

How many NULL files we can create using a single IEBGENER step.

Below is my JCL.Here I'm creating 2 null file.

Code:


//PS030    EXEC PGM=IEBGENER     
//*===========================================
//SYSOUT    DD SYSOUT=*                                               
//SYSDUMP   DD SYSOUT=*                                               
//SORTLIST  DD SYSOUT=*                                               
//SYSPRINT  DD SYSOUT=*                                               
//*                                                                   
//SYSUT1   DD DUMMY,                                                 
//            DCB=(RECFM=FB,LRECL=150,BLKSIZE=0)                     
//SYSUT2   DD DSN=OUTPUT.FILE1, 
//            DISP=(NEW,CATLG,DELETE),                               
//            UNIT=STOR,SPACE=(TRK,(1,1),RLSE),                       
//            DCB=(B0.DSCB,RECFM=FB,LRECL=150,BLKSIZE=0)   
//SYSUT3   DD DSN=OUTPUT.FILE2, 
//            DISP=(NEW,CATLG,DELETE),                               
//            UNIT=STOR,SPACE=(TRK,(1,1),RLSE),                       
//            DCB=(B0.DSCB,RECFM=FB,LRECL=150,BLKSIZE=0)               
//SYSIN    DD DUMMY


Thanks,
Rahul
Back to top
View user's profile Send private message

MBabu

Active User


Joined: 03 Aug 2008
Posts: 401
Location: Mumbai

PostPosted: Sun Nov 01, 2009 8:48 am    Post subject:
Reply with quote

IEBGENER isn't doing anything for you in the example (yes it is copying nothing to the sysut1, but the effect of that is -- nothing).

You could get the same effect calling anything, including a program that doesn't even exist. You'd get an S806 abend, but you would still end up with empty OUTPUT.FILE1 and OUTPUT.FILE2 data sets (ignoring the ,,DELETE for the purposes of illustration, of course).

The point is that IEBGENER isn't allocating the files. JES is and they will get allocated whether the program works (or exists) or not. That's how JCL works. So the answer to your question is "as many dd statements as you can specify" which in most cases that is 3273 minus the required IEBGENER statements (sysin,sysprint, and a dummy sysut1) so 3270. Your JCL has a bunch of useless dd statements. IEBGENER doesn'tuse sysout, sysdump, or sortlist and I'm too lazy to lookup sysut3

Also, there is no term "NULL file" in z/OS. In fact, the term "file" itself is ambiguous since in the MVS file system it refers to a ddname (a logical thing) and in the Unix for z/OS file systems it refers to a Unix file (a physical thing)

(that's one answer. Another answer is "as many as you want", since you can use IEBGENER to copy any number of new jobs read from an instream //SYSIN statement to the internal reader. If you use that answer on a test, even though it is correct, you will, and should, fail icon_smile.gif )
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: Mon Nov 02, 2009 3:02 am    Post subject:
Reply with quote

Hello,

Is this homework of some kind?

Quote:
How many NULL files we can create using a single IEBGENER step.
My guess would be "none" as per the info from MBabu - there is no such thing as a "NULL file" in this enviaonment. When one plays in some technical environment they must be sure to use the proper terminology of that environment and not create some of their own. . .

Quote:
Also, there is no term "NULL file" in z/OS.
Nope, but DSN=NULLFILE has survived. . . icon_smile.gif

And would not apply to this . . .

http://publibz.boulder.ibm.com/cgi-bin/bookmgr_OS390/handheld/Connected/BOOKS/iea2b680/12.1.4

Also, i believe you misunderstand how IEBGENER works (or maybe i do). When SYSIN is DUMMY, the content of SYSUT1 is copied to SYSUT2. The content of SYSUT1 is not copied to the other "output" datasets coded in the JCL. So, SYSUT2 will be opened and closed by IEBGENER and the others will not (which can cause problems if the "output" datasets are not sms-managed and some process tries to read them).
Back to top
View user's profile Send private message
MBabu

Active User


Joined: 03 Aug 2008
Posts: 401
Location: Mumbai

PostPosted: Mon Nov 02, 2009 4:53 am    Post subject:
Reply with quote

dick scherrer wrote:

DSN=NULLFILE has survived. . . icon_smile.gif

ha ha -- I stand corrected - thanks Dick icon_smile.gif
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 Append data from two files into a sin... Praveen04 DFSORT/ICETOOL 5 Thu Mar 16, 2017 7:29 pm
No new posts VALIDATE NULL VALUE IN DB2 CASE STATE... useit DB2 5 Thu Feb 09, 2017 4:34 pm
No new posts High CPU consumption Job using IAM fi... aswinir JCL & VSAM 15 Thu Dec 01, 2016 8:28 pm
No new posts Match or compare two files in VB Format anatol DFSORT/ICETOOL 14 Thu Nov 03, 2016 7:41 pm
This topic is locked: you cannot edit posts or make replies. How to use 2 input files in control c... Gunapala CN DFSORT/ICETOOL 23 Thu Oct 13, 2016 3:42 pm


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