Firebird is an open source SQL relational database management system that runs on Linux, Microsoft Windows, Mac OS X and a variety of Unix. The database forked from Borland's open source edition of InterBase in 2000, but since Firebird 1.5 the code has been largely rewritten | Firebird is an open source SQL relational database management system that runs on Linux, Microsoft Windows, Mac OS X and a variety of Unix. The database forked from Borland's open source edition of InterBase in 2000, but since Firebird 1.5 the code has been largely rewritten |