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bhaskar_kanteti
Active User
Joined: 01 Feb 2007
Posts: 123
Location: Hyderabad
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Hi,
how to define and read a unformatted file in cobol program. I will be getting the file as U type. ie. Unformatted.
when i seen the properties of this U file, the LRECL is 0.
How to define in file section. How to handle this unformatted file in cobol program. Is it different from FB and VB.
Help me in this regard. |
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murmohk1
Senior Member
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Joined: 29 Jun 2006
Posts: 1436
Location: Bangalore,India
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Bhaskar,
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| how to define and read a unformatted file in cobol program. |
Refer 'RECORDING-MODE' and 'read' statements in the COBOL manual. |
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dick scherrer
Moderator Emeritus
Joined: 23 Nov 2006
Posts: 19243
Location: Inside the Matrix
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Hello,
If the file is "unformatted", how will you process it?
What kind of data will/does it contain?
What does the data look like if you view it in tso/ispf or some other editor? |
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stodolas
Active Member
Joined: 13 Jun 2007
Posts: 631
Location: Wisconsin
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U doesn't mean unformatted, it means the blocking for the file is unknown. If the records actually have a layout but have unknown blocking, you would have to read a byte stream and look for indicators that you have read a whole record.
Things just don't deal well with U though. |
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Phrzby Phil
Senior Member
Joined: 31 Oct 2006
Posts: 1049
Location: Richmond, Virginia
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| Dick's question is the key - what are you doing with this file? |
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mmwife
Super Moderator
Joined: 30 May 2003
Posts: 1592
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Hi Bhaskar,
Whoever created this file holds the key to processing it. If you don't know the name of the pgm that created the file, search the JCL/sourcelib(s) at your site to find it.
Then study the code. It will tell you how to acess the data in the file. Then do what you need to do.
PS. The blocks in the file can be either fixed length (as in a PDS directory) or variable in length, but will not contain RDWs or BDWs as V/VB files do. |
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mmwife
Super Moderator
Joined: 30 May 2003
Posts: 1592
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While we're waiting for Bhaskar to reply...
Steve said:
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| you would have to read a byte stream and look for indicators that you have read a whole record. |
Actually, U records can be processed very much like V recs:
Use the same RECORD VARYING.... DEPENDING ON .... clause in the FD or multiple 01 rec descriptions.
READ the file and chk the DEPENDING ON field for the length of the block.
Fill the DEPENDING ON field before issuing each WRITE.
The only difference between V and U is that U recs use the same length in the pgm and JCL, and, there's no block (or is it rec?) w/format U. |
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enrico-sorichetti
Superior Member
Joined: 14 Mar 2007
Posts: 10886
Location: italy
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| Quote: |
| The only difference between V and U is that U recs use the same length in the pgm and JCL, and, there's no block (or is it rec?) w/format U. |
record format undefined, blksize xxxxx
at every read or write operation up to xxxxx bytes are going to transferred
from/to the external medium
from an I/O point of view the logical record is always a full block..
there is no guarantee at all that each block(record) will be of the same size |
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stodolas
Active Member
Joined: 13 Jun 2007
Posts: 631
Location: Wisconsin
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| If it is just a big XML stream you could be fine too. Then who cares what the layout of the data is, just use the cobol XML PARSE. |
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mmwife
Super Moderator
Joined: 30 May 2003
Posts: 1592
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Enrico,
You quoted my post and then commented. I'm not sure of what you disagreed. |
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dick scherrer
Moderator Emeritus
Joined: 23 Nov 2006
Posts: 19243
Location: Inside the Matrix
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Hi Guys,
Maybe i'm still in the fog, but i read it as additional clarification rather than a difference. . .
If i'm still in the fog, shine a light my way. . .  |
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mmwife
Super Moderator
Joined: 30 May 2003
Posts: 1592
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Agreement is usually prefaced with: "To expand on Jack's EXCELLENT comments, ......" 
I think Enrico may have thought that I was saying that all blocks(recs) in a fmt U file are the same. What I meant was that fmt U recs, unlike fmt V recs, don't use a n RDW. |
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dick scherrer
Moderator Emeritus
Joined: 23 Nov 2006
Posts: 19243
Location: Inside the Matrix
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| Quote: |
| Agreement is usually prefaced with: "To expand on Jack's EXCELLENT comments, ......" |
heh heh heh. . .
d |
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enrico-sorichetti
Superior Member
Joined: 14 Mar 2007
Posts: 10886
Location: italy
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Hi Jack,
I was not disagreing
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| ... there's no block (or is it rec?) w/format U. |
I was lazy not to quote the exact fragment I wanted to comment on...
I have always, in my loong years of IT practicing, spoken about
blocks when seen from the point of view of the data management
records when seen from the point of view of the program
maybe was the question mark which made me try to clarify |
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mmwife
Super Moderator
Joined: 30 May 2003
Posts: 1592
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Hi Enrico,
The reason I used the "?" is that I noticed COBOL prohibits the use of the "BLOCK CONTATNS ..." clause for fmt U files, but on the other hand, in the JCL, the DD stmt requires "BLKSIZE= ..." when creating one.
I'm easily confused. |
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