Thanks to all who responded and enlightened me.
________________________________ From: Mark Zelden <[email protected]> To: [email protected] Sent: Thursday, 28 June 2012 2:27 PM Subject: Re: QUESTION ABOUT REF* On Thu, 28 Jun 2012 10:55:18 -0700, John Dawes <[email protected]> wrote: We are evaluating some volume backup jobs which execute about 45 steps in average and write out to the same output scratch tape.� I noticed that some jobs in particular have each step (from the second to the 45th step) refer to the first step e.g. �//�������� VOL=(,RETAIN,,,REF=*.STEP01.TAPE) I know prior to OS390 this was necessary, however this is no longer done.� I personally code the REF=* to point to the previous step instead of STEP01. My question is, if I refer back to STEP01.TAPE, does the tape rewind back to the position where STEP01 dsn was created and then skips forward to write out the next dsn?� Does coding the previous step��for the REF=* save I/O time or there is no difference at all?� I hope I was able to word my question clearly. � I would appreciate your comments before I embark on changing the jcls. ============================== Pointing to the first step prior to OS/390 wasn't required and it was and is a mistake. You always point to the previous step because if file ends up crossing over to a new output volume you will get an abend on the next step. This subject just came up in the last month or so and I couldn't remember the abend code back then and thought it was A13. This time I looked up A13 and I'm pretty sure that is it. I'd run a test, but all my tapes sizes (tapeless environment) are 40G and it takes quite a while to fill one up. :-) -- Mark Zelden - Zelden Consulting Services - z/OS, OS/390 and MVS mailto:[email protected] Mark's MVS Utilities: http://www.mzelden.com/mvsutil.html Systems Programming expert at http://expertanswercenter.techtarget.com/ ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
