Engineers and technicians have used mathematical analysis, in the design of fluid power machinery, for as long as this art has been known. As the machinery became more complex, analysis methods have had difficulty in meeting design needs. Some equation sets appropriate for fluid power devices are very difficult to solve with general mathematical methods.Electronic computers now make it possible to solve complex mathematical models. As fluid power analysis has evolved, software has been produced that is appropriate for fluid power analysis. The question then arises, as to how reliable and accurate this software may be.Some previous studies indicate that different types of software produce results that are quite similar in quality, however, quantitative answers may vary slightly (1, 2)*. This study compares the design analysis results for a fluid power attenuator obtained with the HYSAN** software and a previous study reported in the SAE Transactions (3).