From out of nowhere, the open-source movement is sweeping through the simulation and training industry with all the temperance of a locomotive. Take the Linux® kernel for example. It seemed only a year ago that Linux was considered no more than a hacker's toy or a graduate student's project. But today, Linux is endorsed by nearly every major computer hardware vendor and is found in a wide variety of applications from Web servers to full flight simulators (FFSs).

While known most for the Linux kernel, the open-source movement also includes many other software products, such as real-time operating systems, compilers, libraries, development tools and Web HTTP servers. In fact, the majority of HTTP servers on the Web today are powered by free software.

Yet there are still a lot more questions than answers when dealing with open-source software. As a vendor, how do I differentiate my product? As a software developer, how do I license my product and protect my intellectual property? As an end user, how do I service and maintain my systems? This paper looks beyond the hype and addresses these and other difficult questions that are associated with open source software.

In addition, also addresses both positive and negative common misconceptions about open source software. Finally, it gives examples of how open-source software is being used in simulation and training systems today and provides some lessons learned for those not yet following the open source herd.