CSP: A Practical Process Algebra

We recall our work with Tony Hoare in developing the process algebra form of CSP. The semantics we developed with him, based on sets of observable linear behaviours, led to a very distinctive style of practical application using refinement checking, as embodied in the FDR model checker. We outline the history of FDR, showing how its power has been enhanced over time, and we showcase some major industrial applications to demonstrate its versatility. We show that CSP is a process algebra with firm semantic foundations and a wide range of practical applications. In doing so we pay tribute to Tony’s profound and continuing influence.