The use of Linux for real-time simulation has become a popular topic of debate. The decision of whether or not to use Linux is a difficult one without actual data on real-time programs common to the simulation/training community. The Air Force Research Laboratory / Mesa Research Site, AFRL/MRS, has ported a demanding but typical computer generated forces program and tested its functionality on several operating systems commonly used in simulation.

Linux is gaining popularity and functionality in the simulation community. However, the demands of hard real-time applications have produced a niche market of very powerful operating systems. While the performance of popular real-time operating systems is good, the cost is high. Users of popular real-time operating systems must pay for the development environment, compilers, technical support, and the operating system including royalties. Linux provides the benefit of being open source and also is generally less expensive than proprietary software. There also is a large Linux user community that is extremely helpful in answering questions that arise. AFRL/MRS was interested in reducing the cost of using proprietary real-time software by using Linux for flight simulation.

AFRL/MRS performed tests using actual simulation code to compare the real-time capabilities of several popular proprietary operating systems typically used in simulations to the performance of a standard Linux distribution. The tests were conducted using the physics based threat generator that is currently being used at AFRL/MRS in their high-fidelity four-ship F-16 simulators.

A second test was performed to determine the behavior of Linux under various simulation frame rates and computational loads.

The results and recommendations of the MRS findings for Linux applicability and durability for real-time simulations are documented in this report