> -----Original Message----- > From: IBM Mainframe Discussion List > [mailto:[EMAIL PROTECTED] On Behalf Of David Andrews > Sent: Wednesday, May 17, 2006 4:04 PM > To: [email protected] > Subject: Re: Dataset contention on GDG > > > On Wed, 2006-05-17 at 14:07 -0500, McKown, John wrote: > > I think it is so that when a job starts, that the > > relative generation number always maps to the same absolute > generation > > The initiator maintains the "GDG name table" (I think that's it) which > is a series of SWA control blocks queued off the JCT. Each control > block has eyecatcher "GDGN" and holds up to three entries: a > 35-byte GDG > base name and a four-byte base generation number. "+0" refers to this > base generation number throughout the job's execution. > > -- > David Andrews
I am aware of the GDG bias number. However, I think what that is used for is so that if the job creates a +1 (or some other + generation) in a step, it knows to adjust the minus numbers (and zero) in subsequent steps. E.g. after a step creates a +1, that absolute generation is now really +0 according to the catalog. So a later step which references +0 has that number adjusted by the GDG bias number to become, in this case, the -1 generation during catalog lookup. -- John McKown Senior Systems Programmer HealthMarkets Keeping the Promise of Affordable Coverage Administrative Services Group Information Technology This message (including any attachments) contains confidential information intended for a specific individual and purpose, and its content is protected by law. If you are not the intended recipient, you should delete this message and are hereby notified that any disclosure, copying, or distribution of this transmission, or taking any action based on it, is strictly prohibited. ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
