Originally published in December, 1998, Falcon 4.0 was the latest iteration of a PC-based simulator of the General Dynamics F-16 Fighting Falcon. One of the features still not duplicated to this day in other flight simulators was the inclusion of a dynamic campaign system that allowed you to fight the tactical air war over North and South Korea in real time.
The Falcon line of games was always plagued by bugs, and patches were fairly common. At some point, the source code for Falcon 4.0 leaked out, and groups of Falcon enthusiasts with coding experience proceeded to continue fixing and developing the Falcon 4.0 engine.
Benchmark Sims is one of those groups. The current release is BMS 4.32, and can be downloaded from their website at www.benchmarksims.org