Research on concurrent systems requires modelling, simulation and evaluation in many settings. We describe a design for Interchangeable Simulation and Implementation (ISI, pronounced easy), an approach that enables the simultaneous modelling, simulation and evaluation of highly concurrent process based systems.

We describe how ISI can been used to design and evaluate techniques used in storage systems. Our key insight is that, while the simulation of systems could be implemented as regular discrete event simulation, the benefits of designing it as the highly concurrent process based system that it is — with the full data and control flow in mind — enables seamless interchangeability between discrete and real time simulation.