A design tool for large scale fault-tolerant software systems

In order to assist software designers in the application of fault-tolerance techniques to large scale software systems, a computer-aided software design tool has been proposed and implemented that assess the criticality of the software modules contained in the system. This information assists designers in identifying weaknesses in large systems that can lead to system failures. Through analysis and modeling techniques based in graph theory, modules are assessed and rated as to the criticality of their position in the software system. Graphical representation at two levels facilitates the use of cut set analysis, which is our main focus. While the task of finding all cut sets in any graph is NP-complete, the tool intelligently applies cut set analysis by limiting the problem to provide only the information needed for meaningful analysis. In this paper, we examine the methodology and algorithms used in the implementation of this tool and consider future refinements. Although further testing is needed to assess performance on increasingly complex systems, preliminary results look promising. Given the growing demand for reliable software and the complexities involved in the design of these systems, further research in this area is indicated.