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abhisun · Beginner Joined: 20 Nov 2003 Posts: 21 Topics: 9

How much BLKSIZE actually is given by system when we specify BLKSIZE=0 ?

One of my production job is creating a dataset(say D1) with following :-
DCB=(SYS2.DSCB,RECFM=VB,LRECL=6132,BLKSIZE=0)

and one step is copying data from a dataset(say D2, with same attributes as above). But sometimes(say once in thousand runs) the copy step (D2 => D1) abends saying 'record length/type altered'

What I suspect is that the BLKSIZE=0 gives authority to system to decide a suitable BLKSIZE, but due to some problem sometimes the system decides BLKSIZE lower than that of record length & thats where I get an abend( For eg. blksize = 4000 for RECL=6132)

Can someone please assist ?

Thanks!

kolusu · Posted: Mon May 17, 2004 5:01 am Post subject:

abhisun,

As far as I know , the blocksize of a dataset can never be less than the lrecl of the file. So your theory of the blksize causing the problem can be ruled out. You need to provide more details the entire error message along with message number. Anyway check this link which discusses blksize=0

http://www.mvsforums.com/helpboards/viewtopic.php?t=130&highlight=blksize

Hope this helps...

Cheers

Kolusu
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slade · Posted: Tue May 25, 2004 2:18 pm Post subject:

Hi abhisun,

As I recall the lrecl stated in a DD stmt for a V or VB file is the MAX lrecl that can be written to it.

You don't say if the pgm(s) referencing the file are utilities or "home grown" COBOL pgms.

If COBOL pgms, you define the limits of the record in the FD (speciically the RECORD CONTAINS clause. In it you state the minimum rec length and the maximum.

There's also the AWO issue, but that concerns the blksize more than the lrecl. In any event I don't think we have enough info for that right now.

Regards, Jack.