SIERA (System for Implementing and Evaluating Robotic Algorithms) is a multiprocessor system that has been developed at the Laboratory for Engineering Man/Machine Systems (LEMS) at Brown University. It incorporates a tightly coupled bus-based system (the Real Time Servo System) and a loosely coupled point-to-point network (the Armstrong Multiprocessor System). SIERA is capable of controlling many types of commercially available robots because the modular construction of its hardware and software has minimized robot dependencies. Three programming levels are introduced to classify the different ways SIERA can be utilized-for simple robot operation, for robotics research, and for system enhancements. The environment associated with each of these levels provides the necessary programming support and interactive commands. The concepts of servo loops and controller modifications (cmods) are introduced to facilitate programming on the Real Time Servo System. A simple example is presented to illustrate operation of the system.