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Is Blocksize of a file with RECFM=F equal to the LRECL?

 
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niks_jude
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PostPosted: Tue Jan 29, 2008 12:47 pm    Post subject: Is Blocksize of a file with RECFM=F equal to the LRECL?
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Is it necessary that for a file with RECFM=F, the blocksize would be required to be equal to LRECL?

Two thing I would like to mention additionally -
1) I tried the manual but could not find any information about this.
2) I tried RECFM=F PS files with different LRECL without giving blocksize and their Blocksize was equal to the LRECL.
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enrico-sorichetti

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PostPosted: Tue Jan 29, 2008 12:50 pm    Post subject: Reply to: Is Blocksize of a file with RECFM=F equal to the L
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You are asking about recfm F ...
==> record format fixed ...
==> unblocked...
==> LRECL = BLKSIZE

as per specifications

( ==> stands for implies )
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niks_jude
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PostPosted: Tue Jan 29, 2008 1:23 pm    Post subject:
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Ok. So that means the blocksize for a RECFM=V file is the largest LRECL.
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srinathangya

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PostPosted: Tue Jan 29, 2008 1:55 pm    Post subject:
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Hi there.. Whether LRECL and BLKSIZE shud be equal or different depends upon the type of application u r using. Blocks are the unit of information transferred between DASD and buffer. If U r using a sequential file, then it is recommended to have block size to be as big as possible. This reduces the data transfer time. If U r using say an Index file, where, U pick the record depending upon the key value, it is better to go with the LRECL and Blksize the same. If U r unsure better leave LRECL and BLKSIZE with the same value.

Hope i havent said anything wrong :-)
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dick scherrer

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PostPosted: Tue Jan 29, 2008 10:35 pm    Post subject:
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Hello,

Quote:
So that means the blocksize for a RECFM=V file is the largest LRECL.
Yes, however recfm=v is seldom used. Most variable files are VB and then blksize is usually not the largest lrecl.
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Frank Yaeger

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PostPosted: Wed Jan 30, 2008 12:16 am    Post subject:
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Hmmm ... I was under the impression that for a VB file, the BLKSIZE must be at least LRECL+4 to allow for the 4-byte BDW. I thought that was true for RECFM=V as well. Not so for one or both?

I tried some experiments and couldn't actually write records into a file with RECFM=V,LRECL=80,BLKSIZE=80. If I specified that for IEBGENER's SYSUT2 and then used DFSORT to display it, it showed the BLKSIZE as 84.
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dick scherrer

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PostPosted: Wed Jan 30, 2008 12:58 am    Post subject: Reply to: Is Blocksize of a file with RECFM=F equal to the L
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Hello,

Quote:
I was under the impression that for a VB file, the BLKSIZE must be at least LRECL+4 to allow for the 4-byte BDW. I thought that was true for RECFM=V as well. Not so for one or both?
Yup, true for both.

My answer was a bit incomplete icon_redface.gif

d
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