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The Jet Propulsion Laboratory (JPL) of Pasadena, California is one of the space program's major players. Managed for NASA by the California Institute of Technology, JPL is the lead US center for robotic exploration of the solar system and its spacecraft have visited all known planets except Pluto. In addition to its work for NASA, JPL conducts research and development projects for a variety of federal agencies. One such project, the Corps Battle Simulation (CBS) recently made the transition from VAX to Red Hat Linux Version 7.0, resulting in a substantial increase in performance at considerably reduced cost.

CBS has been used to train army officers in battle tactics for over 15 years. Previously, it ran on VAX's most powerful computer, a $100,000-plus 7800-series machine. However, due to the steadily increasing intelligence and the addition of new features, CBS reached its limitations on VAX. This made further innovation a struggle and threatened to render the battle simulator obsolete within a few years. As a result, the US Army's Simulation, Training, and Instrumentation Command (STRICOM), in Orlando, Florida asked JPL to port the software to Linux in order to increase functionality while cutting cost.

After spending a man-year reconfiguring CBS source code, then recompiling, testing and debugging, the team benchmarked the system running on Linux with rewarding results. “By porting CBS from VAX to Linux, we have achieved far better performance at a much reduced cost and have lots of extra capacity,” says Jay Braun, a simulation software technologist at JPL.

The additional capacity of Linux gives the CBS system more room to expand. Terrain elevation, for instance, can now be modeled at a very detailed level. Previously, attempting complex line of sight calculations severely taxed VAX capabilities. Now, high-fidelity maps are available on Linux that make simulations more realistic, increasing the accuracy of the battle scenarios.

CBS is running on a $4,000 PC with a 1.2 gigahertz AMD Athlon processor. This Linux machine runs the largest CBS exercise almost four times faster than the most powerful VAX without sacrificing anything in model fidelity. Using the VAX, fidelity had to be reduced in order to allow a simulation to progress at a one-to-one game ratio, i.e., a virtual minute in the simulation requires a real minute of execution time. Under Linux, however, one-to-one scenarios can be achieved at the highest quality levels available.

JPL has also made adjustments so that CBS has a 20-second save time for the largest exercises and three seconds for small exercises. This is an order of magnitude faster than on the old VAX system. Under Linux the application can now represent almost 3GB of virtual address space for each simulation. “That's a big image!” says Braun. “Our model has plenty of features that are pushing the limits of Linux.”

JPL will deliver the ported software in June of 2001. Braun predicts that in the near future, the system will further advance to a two-processor machine that can support additional simulations. JPL is now shifting over to Red Hat Linux 7.1 with the new 2.4 kernel.

No text selections can be copied from this book to the clipboard....No printing is permitted on this book.... This book cannot be lent or given to someone else....This book cannot be given to someone else....This book cannot be read aloud.

—From the “permissions” that accompany Alice in Wonderland, as published by Adobe in its downloadable .pdf format. Alice in Wonderland, written by Lewis Carroll in 1865, has long since passed into the public domain.

Obviously some protection of copyrighted material will, and should be, built into code. But the power to control perfectly the use of copyrighted material should not. The key will be to find a balance. And when companies like Adobe clearly signal that their effort is to find a balance, they deserve the benefit of the doubt.

—Lawrence Lessig, The Industry Standard, March 27, 2001