Problem:

What is the difference between a Re-Org on the IMS tab and one in the IMSDBU utility?

Is there a host equivalent?

Resolution:

There is a slight subtlety here:

- The reorganization via Tools>IMS>Database Utility, IMSDBU,

   reorganizes the actual database.  

- The reorganization via IMS tab>DBD Gens, right click on DBD,

   reorganizes the database gen files (DB definitions).  

So the first handles the IMS database (the actual data) while the second

handles the DBDs that have been genned (the definitions used by the PSBs).

As to the host equivalent of a DBD Re-Org in MFE?

The answer is that it is just like doing a PDS compress to reclaim freespace. MFE keeps its IMS gen information in Indexed files. The Re-Org for MFS, DBD and PSB gen file in MFE keeps the Indexed files at a minimum number of entries. You should only have to re-org the gen files after adding or deleting a large number of entries.