Mainframe, MVS and zOS Discussion

Hi,

"Version" and "generation" does have their meaning when talking about GDGs. However, when you code HLQ.FIRST.GDG(+1) -- next GENERATION gets created.

No version (V00 to V01 or whatever you can think of) increments/changes happen, whatsoever. Version is still "00". Said that, You can still create the next version BUT neither it's advised nor it will be 'attached' to the GDG-base.

If generation HLQ.FIRST.GDG.G0001V00 is cataloged and you now create and catalog HLQ.FIRST.GDG.G0001V01, this is just another DSN but as the "base" is same, the new entry is cataloged in the location previously occupied by HLQ.FIRST.GDG.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.

In simple words - "Version" and "generation" are two separate entities though they both, in the context of this topic, belong to GDG.

This is a nice information but does that mean version is never used?

Version is used, but rarely. If a generation is built and it is later determined that the data is wrong, a new version may replace that generation for various reasons. Since the new version must be fully specified (the relative generation approach cannot be used), the JCL has to be customized for that one data set.

FWIW -NONE of my clients permit the use of versions for business application datasets.

I too agree with that idea - having version/s confuses you more than it helps - Dick.