SURF-2-a tool for modeling and evaluation of dependability measures

SURF-2 is a software tool for evaluating system dependability. It is especially designed for an evaluation based system design approach in which multiple design solutions need to be compared from the dependability viewpoint. SURF-2 allows the user to describe the model behavior using generalized stochastic Petri nets (GSPNs) whose reachability graph is then interpreted as a Markov chain, or enter directly a Markov chain. In the case of GSPNs, it enables the models to be verified in terms of their structural properties. The tool supports the evaluation of different measures of dependability, including pointwise measures, asymptotic measures, mean sojourn times and, by superposing a reward structure onto the behavior model, reward measures such as expected performance or cost. These measures are obtained by processing the Markov chain. SURF-2 can be viewed as a toolbox where each tool can operate independently on objects gathered in a database managed by a supervisory task.