2 What Is New In

We present the Stochastic Petri Net Package (SPNP), a versatile modeling tool for performance, dependability, and performability analysis of complex systems. Input models developed based on the theory of stochastic reward nets are solved by e cient and numerically stable algorithms. Steady-state, transient, cumulative transient, time-averaged, and \up-to-absorption" measures can be computed. Parametric sensitivity analysis of these measures is possible. Some degree of logical analysis capabilities are also available in the form of assertion checking and the number and types of markings in the reachability graph. Advanced constructs available such as markingdependent arc multiplicities, guards, arrays of places and transitions, and subnets reduce modeling complexity and enhance power of expressiveness of the package. The most powerful feature is the capability to assign reward rates at the net level and subsequently compute the desired measures of the system being modeled. The modeling description language is CSPL, a C-like language, although no previous knowledge of the C language is necessary to use SPNP.