On Wed, 21 Aug 2013 08:53:25 -0700, Skip Robinson <jo.skip.robin...@sce.com> wrote:
>We're having ongoing 'discussions' with our tape vendor over through-put >performance. Vendor is suggesting that we should be using modern man-size >blocks like 256K. I did some simple testing yesterday to satisfy myself >that--whatever it might take to super-size our tape file blocks--simply >adding > > BLKSIZE=some-large-number > >to a DD card will not cause the creation of very large blocks. After >running such a job with an existing RYO program, the resulting BLKSIZE was >in fact 32K. No error messages, just no big blocks. > >Am I right in asserting that, whatever benefit we might derive from >uber-blocks, we cannot get there by fiddling with JCL? > >. >. >JO.Skip Robinson >Southern California Edison Company >Electric Dragon Team Paddler >SHARE MVS Program Co-Manager >626-302-7535 Office >323-715-0595 Mobile >jo.skip.robin...@sce.com > >---------------------------------------------------------------------- >For IBM-MAIN subscribe / signoff / archive access instructions, >send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN The application/utility being used must also provide LBI support, normally. This condition would be similar to application support for DSNTYPE=LARGE and EAV/EAS, as it stands. For example, IDCAMS REPRO does support LBI, starting at z/OS 2.1, per DOC. And DFDSS ADRDSSU supports it currently, of course short-circuited if someone has BLKSIZE=32760 hardcoded. And, for comparison, SAS 9.2 provided limited support, but only for external tape-directed file access, not SAS databases residing on tape -- that is coming soon. Suggest contacting IBM and ISVs through their support "reference database search" resources on a product by product basis -- and don't get hopes up that all ISVs have done their 'technology support' due-diligence on the customer's behalf. Scott Barry SBBWorks, Inc. ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN
