New tools help render simulation systems interoperable

WASHINGTON - In less than five months all military simulation systems must begin complying with the Defense Department`s High Level Architecture (HLA).

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By John Rhea

WASHINGTON - In less than five months all military simulation systems must begin complying with the Defense Department`s High Level Architecture (HLA).

In preparation, leaders of a Canadian company are offering a set of standard software tools known as frameworks to enable simulation industry engineers to convert their object-oriented software to the new architecture by only writing 30 percent new code.

Developing the tools were software engineers at OriginalSim Inc. of Montreal in cooperation with Rational Software Corp. in Santa Clara, Calif.

The HLA is an important part of the next generation of modeling and simulation software that will create a common technical framework to improve interoperability across a wide spectrum of applications and components.

The idea behind the OriginalSim tool is to reuse common building blocks to generate new code automatically for legacy systems, thus saving development time and lifecycle costs, says OriginalSim`s president, Carl Byers. Not writing new code also reduces human error, he adds.

The company`s latest version, OSim 4.0, announced last month, works on Sun and Silicon Graphics workstations and automatically generates C++ code. A follow-on version, to be introduced later this year, will extend this to Windows NT and Java. The frameworks, first released in early 1996, cost about $35,000 and encompass half a million lines of code.

For systems developers, finding an economical method of conversion to HLA is urgent. Development or modification of simulation systems that are not HLA-compliant must cease by Oct. 1. Moreover, all non-compliant systems must be phased out by October 2000.

This order comes from Under Secretary of Defense Paul Kaminski`s directive of 10 Sept. 1996. Kaminski`s order was broad ranging, and included all simulation systems ranging from design and development to training.

Software for simulation traditionally has been written in Fortran and later in C and Ada, but the trend is toward powerful languages with an accompanying requirement that the systems be interoperable across the military services and applications. Another need is to run on multiple workstations.

Simulations originally written to support design efforts could flow "up the food chain" to acquisition and "downstream" to logistics, according to Byers. He estimates that engineers write 15 percent of simulation software in object-oriented code today.

He likens the situation, particularly the reuse of code, to the evolution of computer-aided design and manufacturing, better known as CAD/CAM.

Design and test has replaced training as the principal function of simulation inn what is estimated as a $6 billion annual aerospace and defense simulation market, Byers says.

Military researchers have been particularly active in applying object-oriented programming to the design function, and now this technology is expanding to applications such as health care management and air traffic control simulation.

Officials of the U.S. Air Force Air Mobility Command are using the OSim tool for analysis, while those at the Navy`s Undersea Warfare Center and the Army`s White Sands Missile Range are using it for test and evaluation.

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Training simulations such as the one depicted above from Evans & Sutherland all are to be subject to new compatibility guidelines of the High Level Architecture.

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