Mainframe, MVS and zOS Discussion

Hi,

This is asked in an interview that consider a GDG like G0001V00: when would you change the version from 00 to 01? My answer was, I have never done it but obviously the interviewer was looking for some better answer...appreciate if someone can help me in this.

Hi Abhay

Please check this link

viewtopic.php?f=62&t=1740

when would you change the version from 00 to 01?

When you need to replace a generation and cannot merely delete the generation and rerun the program that created the generation (for whatever reason -- such as more recent generations have been added to the GDG base). You must specify DSN=A.B.C.GxxxxV01 (that is, you CANNOT use (+1) to specify the new version -- you must give the full data set name including the generation number and V01), along with the usual data set characteristics.

This is usually not required however in a rare case as Robert has described, you might do this and you should properly document it. OTOH, if generation HLQ.SLQ.G0001V00 is cataloged and you now create and catalog HLQ.SLQ.G0001V01, this is just another DSN but as the "base" is same, the new entry is cataloged in the location previously occupied by HLQ.SLQ.G0001V00. The old entry is removed from the catalog, to make room for the newer version, and may or may not be scratched depending on what limit processing options are specified for the GDG base.