On the design of ORBIT

Design of highly complex systems relies on effective utilization of multiple tools. The tools vary with the aspect of the design the user is currently interested in. Also, the approaches used to verify the correctness of the design are different for different domains. Because of the importance of verifying the correctness of the design, there is considerable interest in utilizing the different approaches and tools in a complementary manner to provide higher degrees of assurance. Unfortunately, due to constraints on the model representations and incompatibilities among the various tools, heterogeneous design and analysis is not feasible. The ORBIT project was envisaged to address this problem. ORBIT is an heterogeneous, component-based design and analysis environment. This paper presents the original requirements of this environment, details the various design decisions taken towards satisfying the requirements, and presents an overview of the implementation. In particular it discusses the generic framework used (GRAVITY), the integration of simulation and formal verification within the design process, automatic generation of proof obligations for checking designs, verification of constraints in the designs and work on re-usability using persistent storage.