Star tool: reengineering for Ada and C

The aerospace industry has a tremendous investment in legacy software that is embedded in mission-critical systems. Often, this software is hosted on obsolete computers, was designed with older paradigms, such as structured analysis, and is coded in older languages, such as C and Ada 83. At the same time, customers for legacy systems want more system performance, reduced software maintenance costs, but minimal software upgrade risk. To accomplish this, legacy software must be modified to run on new, more powerful COTS processors. It is also desirable to enhance the software´s reusability and maintainability by making it more object-oriented, while not breaking it in the process. For several years, Raytheon has been working with Dr. William Griswold at the University of California at San Diego, on the development of a unique reengineering tool that produces graphical representations of source code called Star Diagrams. Experiments at Raytheon with this tool have shown it to be extremely valuable for understanding legacy software and facilitating the task of modifying code to perform on new, open system platforms. This paper describes the Star tool, Raytheon´s experience using it, and lessons learned about reengineering and reusing legacy software in an open system environment