Using partial-order methods in the formal validation of industrial concurrent programs

Formal validation is a powerful technique for automatically checking that a collection of communicating processes is free from concurrency-related errors. Although validation tools invariably find subtle errors that were missed during thorough simulation and testing, the brute-force search they perform can result in excessive memory usage and extremely long running times. Recently, a number of researchers have been investigating techniques known as partial-order methods that can significantly reduce the computational resources needed for formal validation by avoiding redundant exploration of execution scenarios. This paper investigates the behavior of partial-order methods in an industrial setting. We describe the design of a partial-order algorithm or a formal validation tool that has been used on several projects that are developing software for the Lucent Technologies 5ESS/sup (R/) telephone switching system. We demonstrate the effectiveness of the algorithm by presenting the results of experiments with actual industrial examples drawn from a variety of 5ESS application domains.