Using visualization to maintain large computer systems

The Year 2000 software conversion effort dramatically illustrates how time consuming and costly maintaining large computer systems can become, especially when each system consists of millions of lines of source code. Understanding how a system's components interact is a key factor in implementing portfolio-wide changes, adding new features, and providing ongoing system maintenance. Any help that software developers can get in making existing software systems easier to understand improves developer productivity, enhances software quality, and reduces development cycles, all leading to faster time to market. The paper discusses the Visual Insights code viewer, a visualization application developed specifically to address the problem of working with large amounts of source code. Used within the Lucent Technologies 5ESS Switch development environment, the code viewer has resulted in increased software developer productivity. In addition, a systems integrator currently uses this tool to help understand and correct the Year 2000 date references in customer software.