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
 

 

How can VSAM file be opened in I-O mode?

 
Post new topic   Reply to topic    IBMMAINFRAMES.com Support Forums -> JCL & VSAM
View previous topic :: :: View next topic  
Author Message
niks_jude
Warnings : 1

Active User


Joined: 01 Dec 2006
Posts: 144
Location: Mumbai

PostPosted: Fri Feb 08, 2008 12:22 pm    Post subject: How can VSAM file be opened in I-O mode?
Reply with quote

How is OPEN I-O possible on empty VSAM file as we have to read once before writing in I-O mode and as we know we cannot do a read on an empty VSAM file.
Back to top
View user's profile Send private message

expat

Global Moderator


Joined: 14 Mar 2007
Posts: 8593
Location: Back in jolly old England

PostPosted: Fri Feb 08, 2008 12:59 pm    Post subject:
Reply with quote

Then you have answered your own question.

This has been discussed before, open in write mode, write dummy record, close, open I-O mode delete dummy record. The file is then initialised.

Why, oh why, most sites do not impose a key '00'X header and key 'FF'X trailer rule when a file is set up I will never know.
Back to top
View user's profile Send private message
niks_jude
Warnings : 1

Active User


Joined: 01 Dec 2006
Posts: 144
Location: Mumbai

PostPosted: Fri Feb 08, 2008 1:06 pm    Post subject:
Reply with quote

Hi Expat,

I just read that you can open an empty VSAM file in I-O mode, when the access mentioned is random or dynamic. If we do a READ in I-O mode, would not it fail?
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: Fri Feb 08, 2008 8:22 pm    Post subject:
Reply with quote

Hello,

Have you coded as Expat suggested?
Quote:
open in write mode, write dummy record, close, open I-O mode delete dummy record. The file is then initialised.
Did it work?

Did you try to issue a read without writing the "dummy record"? What happened?
Back to top
View user's profile Send private message
superk

Moderator Team Head


Joined: 26 Apr 2004
Posts: 4649
Location: Raleigh, NC, USA

PostPosted: Fri Feb 08, 2008 8:34 pm    Post subject:
Reply with quote

expat wrote:
Why, oh why, most sites do not impose a key '00'X header and key 'FF'X trailer rule when a file is set up I will never know.


Every site I've ever worked at did/does.
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
This topic is locked: you cannot edit posts or make replies. Fetching data from BAI File arunsoods JCL & VSAM 1 Wed Jul 19, 2017 4:28 pm
No new posts Write out NODUPS but just from one file Jay Villaverde DFSORT/ICETOOL 8 Fri Jul 14, 2017 12:44 am
No new posts How to add header with Date(YYMMDD) i... Rajan Moorthy DFSORT/ICETOOL 2 Thu Jul 06, 2017 11:44 pm
No new posts How to generate a new unique Input fi... for1ranjith CLIST & REXX 11 Sat Jul 01, 2017 12:09 pm
No new posts Writing a file using online program grvtomar PL/I & Assembler 3 Fri Jun 30, 2017 1:06 pm


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