The key elements in the study of chemical reaction transients are generation of forcing functions, rapid measurement of process variables and reliable computer control system. A multicomponent reaction involving propene metathesis was studied under computer control. The real-time control of the inlet gas concentrations to a Berty reactor, reactor temperature measurement and control, and acquisition of reactor effluent composition via rapid analysis in a gas chromatograph are described. The time intervals for servicing the interfaced devices were generated by hardware interrupts. The multitasking computer control program with interrupt servicing was written in FORTH.