Portal | Manuals | References | Downloads | Info | Programs | JCLs | Mainframe wiki | Quick Ref
IBM Mainframe Computers Forums Index
 
Register
 
IBM Mainframe Computers Forums Index Mainframe: Search IBM Mainframe Forum: FAQ Memberlist Profile Log in to check your private messages Log in
 
BLKSIZE in COBOL and DCB Parameter

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

New User


Joined: 20 May 2008
Posts: 21
Location: bangalore

PostPosted: Sun Jun 29, 2008 5:23 pm    Post subject: BLKSIZE in COBOL and DCB Parameter
Reply with quote

Hi forum,


I have a confusion on how the BLKSIZE is determined.


In SELECT clause it s coded as

BLOCK CONTAINS 0 RECORDS

And DCB parameter contains BLKSIZE=800.

Which block size will be considered here.whether sys determines the effective size or the jcl value is taken.

Please suggest me.
Back to top
View user's profile Send private message

Craq Giegerich

Senior Member


Joined: 19 May 2007
Posts: 1512
Location: Virginia, USA

PostPosted: Sun Jun 29, 2008 8:33 pm    Post subject:
Reply with quote

I hope you have block contains 0 records in the FD and not in the select.

From the Enterprise COBOL Language Reference.

BLOCK CONTAINS 0 can be specified for QSAM files. If BLOCK CONTAINS 0 is specified for a QSAM file, then:

The block size is determined at run time from the DD parameters or the data set label. If the RECORD CONTAINS 0 CHARACTERS clause is specified, and the BLOCK CONTAINS 0 CHARACTERS clause is specified (or omitted), the block size is determined at run time from the DD parameters or the data set label of the file. For output data sets, with either of the above conditions, the DCB used by Language Environment will have a zero block size value. If you do not specify a block size value, the operating system might select a System Determined Block Size (SDB). See the operating system specifications for further information on SDB.
Back to top
View user's profile Send private message
baramesh

New User


Joined: 20 May 2008
Posts: 21
Location: bangalore

PostPosted: Mon Jun 30, 2008 12:05 pm    Post subject:
Reply with quote

Opps Please accept my apologies.And thanks for your time, answering the question
Back to top
View user's profile Send private message
manojtyagi_09

New User


Joined: 30 Oct 2006
Posts: 10

PostPosted: Mon Jun 30, 2008 1:55 pm    Post subject:
Reply with quote

Its always better to write Block contains 0 records/characters in COBOl program. So that u can specify the BLKSIZE in JCL.

Supppose there is a requiremet to change the BLKSIZE due to change in LRECL this will cause only change in BLKSIZE in JCL. if you mention BLOCK contains N records in COBOL program. then it is required to match with BLKSIZE in JCL also it wud be required to change COBOL + JCL both.
Back to top
View user's profile Send private message
robertovon

New User


Joined: 26 Jun 2008
Posts: 1
Location: San Antonio, Texas, USA

PostPosted: Mon Jun 30, 2008 9:34 pm    Post subject: Reply to: BLKSIZE in COBOL and DCB Parameter
Reply with quote

It will use 800.
If you code BLKSIZE=0 in your DCB, the system will dtermine the most efficient block size for space utilization.
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 DUMMY When do I need add a DCB parameter Martylin JCL & VSAM 3 Fri Dec 08, 2017 7:20 am
This topic is locked: you cannot edit posts or make replies. Cobol to fetch the content by using s... arunc55 COBOL Programming 4 Fri Nov 17, 2017 1:25 pm
No new posts VBS and VB, COBOL syntax is the same ... natt.sut COBOL Programming 3 Sun Nov 12, 2017 6:36 am
No new posts COBOL - EXIT statement weird behavior anthony.pangestu COBOL Programming 0 Fri Oct 27, 2017 9:57 am
No new posts IEW2456E error when link-editing a C ... Senthilraj JCL & VSAM 0 Fri Oct 13, 2017 3:12 pm

Facebook
Back to Top
 
Job Vacancies | Forum Rules | Bookmarks | Subscriptions | FAQ | Polls | Contact Us