This paper describes the software package DSPNexpress 2000, a tool for the quantitative evaluation of systems specified in stochastic Petri nets, the Unified Modeling Language (UML), or other specification languages for discrete-event systems. Linking the DSPNexpress software to commercial UML design packages allows the effective computation of performance measures like throughput and delay for UML system specifications. The unique feature of DSPNexpress constitute numerical solvers or transient and steady-state analysis of generalized-semi Markov processes with exponential and deterministic events, which may be concurrently active. The applicability of the DSPNexpress software for practical performance and dependability projects is demonstrated by an UML specification of an alternating bit protocol. The computational effort required by DSPNexpress for transient and steady-state analysis is plotted for varying model size. Furthermore, a performance curve for a measure of interest is presented.