The Enterprise Server Service is essentially the "CONNX Server/Listener" component that normally resides on a non-windows platform, wrapped into a windows  service.  If the data source being accessed resides on windows, normally the CONNX driver will directly load the DLLs necessary to establish a direct connection to the data source, eliminating the need for the Server/Listener architecture that exists for non-windows datasources like VSAM, Adabas, and RMS for example.

 

However, there are sometimes advantages of having the "split stack" architecture, even if all components are on windows.  Some of the advantages include:

• The ability to access 32bit only data sources from a 64bit client.  See 64bit to 32bit ODBC and OLE DB Bridge.

• 3rd party connectivity software (such as the Oracle OCI Client, or the SQL Server Driver) only needs to be installed in a single central location, instead of being installed on every desktop where CONNX resides.  In large organizations, this can significantly reduce configuration headaches of trying to keep everyone's tnsnames.ora in sync for example.

• In the case of Adabas, if Entire Network is required to access a version of database that does not have a Native CONNX Data Server, Entire Network only needs to be installed on a single central server instead of every desktop.