Paul.. I've never paid that close of attention to say if it is "CLOSE"D or "FREE"D. All I remember is when the job that was creating a new generation completed other jobs could "access" the GDG by the relative generation.
As for writes/creation I never tried to use the full name. I only did it for reads. I'm not sure how the system would handle the roll in process. Thanks.. Paul Feller AGT Mainframe Technical Support -----Original Message----- From: IBM Mainframe Discussion List [mailto:IBM-MAIN@LISTSERV.UA.EDU] On Behalf Of Paul Gilmartin Sent: Tuesday, September 12, 2017 16:07 To: IBM-MAIN@LISTSERV.UA.EDU Subject: Re: GDG +1 dynamic allocation collision between two concurrent jobs On Tue, 12 Sep 2017 15:40:16 -0500, Tom Marchant wrote: >>> >>What does a relative generation number greater than +1 mean? > >If you create a Generation Data Set with JCL using +1 in one step, >and want to refer to it in a subsequent step in the job, you >reference it as +1. If you want to create another GDS for the same >GDG, you would specify +2. > OK. If a job uses +2 but never mentions +1, is an error reported? What if the step that creates +1 is skipped by COND or IF? >In a subsequent job, assuming no other GDS created for that GDG, >these same data sets would be -2 and -1. > Then I'd have expected -1 and 0. But I'm often wrong. Fencepost errors and all. On 2017-09-12, at 14:30, Feller, Paul wrote: >I think someone mentioned WAD. If I remember correctly when using the +1 the >system does an enqueue on the BASE as part of the process. The enqueue is not >release until the file is closed. I believe this is done to insure proper >"roll in" of the new generation. > "CLOSE"d or "FREE"d? >I believe this same behavior happens when you are reading a GDG by the +1 or >+0 or whatever. Any new allocation of the GDG will fail or hang until the >other job closes the file it is reading. For reads I have gotten around this >by doing the allocation using the full dataset name. > Would that not also work for writes? Or can a generation be written only once? The OP mentioned BPXWDYN. Can the "full data[ ]set name" be found by BPXWDYN(INFO ...) or BPXWDYN( ALLOC RTDSN(...) ...)? -- gil ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN
