On Wed, 2006-02-15 at 16:29 -0500, Bruce Black wrote:
> > What does ISMF say about your default device geometry?
> I am pretty sure that the SMS default geometry only affects space
> calculations, converting CYL and TRK requests to bytes, and does not
> affect SDB
I think Bob Rutledge has nailed the discrepancy. He pointed out to me
that in "Using Datasets":
"Each block in an extended-format data set has a
32-byte suffix, which is added by the system.
Your program does not see this suffix, but you
might need to consider it when you calculate
disk space requirements."
I retested SDB for non-SMS, SMS and SMS-EF, with the result:
LRECL BLK (non-SMS) BLK (SMS) BLK (EXT)
6991 27964 27964 27964
6992 27968 27968 6992
6999 27996 27996 6999
7000 7000 7000 7000
So extended-format datasets are blocked differently by SDB, likely due
to that 32-byte suffix. Yes, 8 != 32, but there is other block overhead
and a block has to fit in an integral number of cells. See:
http://publibz.boulder.ibm.com/cgi-bin/bookmgr_OS390/BOOKS/AM3U1001/B.1.1?SHELF=AM311903&DT=19930630180527&CASE=
--
David Andrews
A. Duda and Sons, Inc.
[EMAIL PROTECTED]
----------------------------------------------------------------------
For IBM-MAIN subscribe / signoff / archive access instructions,
send email to [EMAIL PROTECTED] with the message: GET IBM-MAIN INFO
Search the archives at http://bama.ua.edu/archives/ibm-main.html
