The location and name of the catalog file is shown in the System Catalog field on the page in ES Admin. You can change this field to use a different catalog file.
To maintain a connection with the mainframe environment, you can continue to use MVS data set names in JCL statements and TSO commands. However, these names have no meaning in a non-mainframe environment, so MSS also requires the name of the local file that represents the data set. Both names are included in the catalog entry.