The Generation data set is in a deferred roll-in status when it is allocated. It becomes part of the rolled in generations during the deallocation phase.
-----Original Message----- From: IBM Mainframe Discussion List [mailto:IBM-MAIN@LISTSERV.UA.EDU] On Behalf Of Tom Marchant Sent: Thursday, November 19, 2015 10:47 AM To: IBM-MAIN@LISTSERV.UA.EDU Subject: Re: Fastest way to read OLDEST GDG entry On Thu, 19 Nov 2015 15:59:37 +0000, J O Skip Robinson wrote: >I haven't experimented with this, but going with NOSCRATCH is likely to >cause big problems with DASD GDGs. A data set residing on an >SMS-managed volume must be cataloged. It has been a long time since I looked at this, but what I remember is that GDGs were a special case. For one thing, with SMS, a data set is cataloged at allocation time, not at step end like it was before. One consequence of that is that is that a generation may be scratched as soon as the new one is allocated, rather than wait until the step ends successfully. Consider a new GDG created with NEW,CATLG,DELETE. Before SMS, the old generation was scratched at the time the new one is cataloged at the end of the step, when the new one is cataloged. As a result, the idea of a generation being rolled in and rolled out was created. The data set is cataloged, but is not cataloged as part of the GDG. -- Tom Marchant ---------------------------------------------------------------------- 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
