This smells like the default geometry in DFSMS is set to a 3380 instead of a
3390. Option 8 in ISMF will allow display of the CDS Base which will show the
defaults being used. Ensure Bytes/track is 56664 (3390 track size).
Cliff McNeill
________________________________
W dniu 23.03.2021 o 09:10, David Staudacher pisze:
> I've looked over all the IBM-MAIN posts referring to AVGREC and don't see
> that anyone has ever brought this up before.
> I've read the relevant manuals, so I'm familiar with AVGREC syntax and how
> it's supposed to work.
> My concern is how to explain the differences in size allocation using
> BLKS/TRK/CYL allocation and what *should be* the AVGREC equivalent, according
> to the reference manuals (e.g. z/OS 2.4 MVS JCL Reference "AVGREC Parameter"
> http://ibm.com/support/knowledgecenter/SSLTBW_2.4.0/com.ibm.zos.v2r4.ieab600/xddavgr.htm
> )
> The discrepancies are consistent across multiple z/OS systems at different
> sites, so I'm certain it is not site-specific.
> Case 1 - SPACE=(TRK,1),DCB=(RECFM=FB,LRECL=80,BLKSIZE=27920)
> With these specs and a 3390 (emulated) Device Type, the file will hold
> *exactly* 698 records.
> These 698 records are then copied to a second file allocated using these
> specs:
> AVGREC=U,SPACE=(80,698),DCB=(RECFM=FB,LRECL=80,BLKSIZE=27920),DISP=(,CATLG)
> But instead of occupying 1 track, the new file occupies 2 tracks. Why?
> Case 2 - SPACE=(TRK,1),DCB=(RECFM=F,LRECL=27920)
> Basically same as above - still 1 track - except now with only 2 records.
> And again, if these 2 records are copied to second file using
> AVGREC=U,SPACE=(27920,2),DCB=(RECFM=F,LRECL=27920),DISP=(,CATLG)
> the new file occupies 2 tracks instead of 1. Why?
> So far, I've run many test cases copying existing files to new files using
> AVGREC and in every case, when the existing allocation is completely full,
> the size allocated to the copy is *always* larger than what is necessary to
> accommodate the input file. In the case of a 100 cylinder input file, the
> excess allocation is over 13 cylinders!
> I have no explanation for this behavior, so I'm hoping someone here will.
>
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