CASPA: A Tool for Symbolic Performance and Dependability Evaluation

Symbolic data structures, such as binary decision diagrams (BDD) [1] and variants thereof have proved to be suitable for the efficient generation and compact representation of very large state spaces and transition systems. The key to such compact representation is the exploitation of the compositional structure of a given specification [2], [3]. It is also known that in addition to functional analysis, performance analysis and the verification of performability properties can also be carried out on such symbolic representations [4], [3]. In this note, we describe the current status of our tool CASPA which offers a Markovian stochastic process algebra language for model specification. CASPA uses multi-terminal binary decision diagrams (MTBDD) [5], [6] to represent the transition systems underlying a given process algebra specification. All phases of modelling, from model construction via numerical analysis to the computation of performance measures, are based entirely on this symbolic data structure.