How to Drive a B Machine

The B-Method is a state-based formal method that describes behaviour in terms of MACHINES whose states change under OPERATIONS. The process algebra CSP is an event-based formalism that enables descriptions of patterns of system behaviour. We present a combination of the two views where a CSP process acts as a control executive and its events simply drive corresponding OPERATIONS. We define consistency between the two views in terms of existing semantic models. We identify proof conditions which are strong enough to ensure consistency and thus guarantee safety and liveness properties.