Dynamic system complexity

Abstract

Both operational environment and source code complexity influence the reliability of software systems. The complex modules of software systems often contain a disproportionate number of faults. However, if in a given environment, the complex modules are rarely exercised, then few of these faults are likely to become expressed as failures. Different environments will exercise a system's modules differently. A system's dynamic complexity is high in an environment that exercises the system's complex modules with high probability. It is likely that one or more potential scenarios induce inordinately large dynamic complexity. Identifying these scenarios is the first step in assuring that they receive the testing time that they warrant. The paper presents two metrics which evaluate the dynamic complexity of systems and of subsystems in the intended operational environment. The authors' analyze two software systems using both dynamic metrics. >