File used by various database client programs to connect to a database; describes properties, such as the data source name and directory, the connection driver, the server address, user ID, and a password; used by ODBC drivers to connect to a specified database, such as a SQL Server or Microsoft Access database.
DSN files are typically stored in a plain text files. However, some client database programs use entries in the Windows registry instead of DSN files.
The ODBC Data Source Administrator included in Windows can be used to create DSN files. It can be found within the Windows Control Panel under Administrative Tools, or in the Start Menu by selecting Programs → Administrative Tools → Data Sources (ODBC).
PCB (printed circuit board) design file created by OrCAD, a program used for designing PCBs; saves the circuit schematic and is often one of several files included in a OrCAD project (.OPJ file); references "symbols," which are the electronic components used to make up the design (stored in .OLB files).