Mainframe, MVS and zOS Discussion

Hi,

I always thought that GDGs are applicable to flat files only but I have also just seen GDGs for PDS too. When do we use GDG for PDS?

I had also noticed that we cannot specify a member name and a relative GDG number at the same time, is it correct or I got it wrong?

Yes, the JCL Reference manual is clear that you can have (member) or (relative generation number) after the DSNAME, but not both. If you have a PDS GDG base, you have to use absolute generation numbers with the member name. It is rare to need a PDS GDG since specifying the data set name is more complex.

This is new information But why would we use GDG for PDS, if we have use it ever?

I can see a use for PDS generations -- there is a daily process that generates files on a server. Those files are transferred via FTP to the mainframe for updating a DB2 data base. If the file names meet PDS member name standards, I could see using a PDS generation to hold each day's data in case of reruns.

Robert Sample wrote: ↑Thu Feb 01, 2018 6:32 pmI can see a use for PDS generations -- there is a daily process that generates files on a server. Those files are transferred via FTP to the mainframe for updating a DB2 data base. If the file names meet PDS member name standards, I could see using a PDS generation to hold each day's data in case of reruns.

But this can be done using the simple GDG Generations too. Right, that is also possible?