-----Original Message----- From: IBM Mainframe Discussion List [mailto:ibm-m...@bama.ua.edu] On Behalf Of Patrick O'Keefe Sent: Monday, August 10, 2009 4:15 PM To: IBM-MAIN@bama.ua.edu Subject: Re: Concatenations and blocksizes
On Mon, 10 Aug 2009 15:20:53 -0500, Mark Zelden <mark.zel...@zurichna.com> wrote: >... >"CONCATENATION ENHANCEMENT: Like-attribute concatenation will be >allowed for eligible data sets with different block sizes in any >order; the largest no longer need be first. Eligible data sets are >partitioned or sequential data sets that are DASD-resident, accessed >by QSAM, and for which the system obtained buffer space. >... Interesting wording. "partitioned ... data sets ... accessed by QSAM ..." If they really meant that, wouldn't that restrict this enhancement to a concatenation sequential datasets and/or PDS members? Doesn't a PDS or concatenation of PDSs have to be accessed by BPAM? <SNIP> No. If you take a program that uses a QSAM DCB and point the DD statement to a PDS with member name, it will read that member and treat it as if it were reading a DSORG=PS data set. The QSAM code will detect end of member and treat that as if it were EOD (and I think it even drives your EOV exit if you have one). So if you concatenate a series of DSORG=PS data sets together, you can't concatenate a PDS as a PDS in the middle. Well, maybe you can, if you forced RECFM=U and BUFL=32760. But enjoy the dir blocks followed by ALL the data blocks (as gas or still in use). OTOH, if you concatenate PDSs together as PDS and then stick in a DSORG=PS I would imagine you will get a very interesting ABEND when the FIND or BLDL that you do doesn't find any directory blocks in the DSORG=PS file (you might even get an early ABEND out of OPEN - I haven't tried this trick in a while). Regards, Steve Thompson -- Opinions expressed by this poster may not reflect those held by poster's employer -- ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@bama.ua.edu with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
