1. A method of simulating a system having a software component and a hardware component, said method comprising the steps of: (i) generating with a test controller a software stimulus for said software component and a hardware stimulus for said hardware component, said software stimulus and said hardware stimulus being associated so as to permit verification of correct interaction of said software component and said hardware component; (ii) modelling operation of said software component in response to said software stimulus using a software simulator; and (iii) modelling operation of said hardware component in response to said hardware stimulus using a hardware stimulator; wherein (iv) said hardware simulator and said software simulator are linked to model interaction between said hardware component and said software component; and (v) said software stimulus is passed to said software simulator by issuing a remote procedure call from said test controller to said software simulator.