On Windows operating systems, ODBC data sources are typically stored in the system registry. File data sources are an alternative, which are stored as files. File data sources are supported on both Windows and UNIX systems.
In Windows, file data sources typically have the extension .dsn. They consist of sections, each section starting with a name enclosed in square brackets. DSN files are very similar in layout to initialization files.
To connect using a File Data Source, use the FileDSN connection parameter. You cannot use both DSN and FileDSN in the same connection.
One benefit of file data sources is that you can distribute the file to users, so that connection information does not have to be reconstructed on each machine. If the file is placed in the default location for file data sources, it is picked up automatically by ODBC. In this way, managing connections for many users can be made simpler.
Embedded SQL applications can also use ODBC file data sources.