A Formal Architecture Pattern for Real-Time Distributed Systems

Pattern solutions for software and architectures have significantly reduced design, verification, and validation times by mapping challenging problems into a solved generic problem. In the paper, we present an architecture pattern for ensuring synchronous computation semantics using the PALS protocol. We develop a modeling framework in AADL to automatically transform a synchronous design of a real-time distributed system into an asynchronous design satisfying the PALS protocol. We present a detailed example of how the PALS transformation works for a dual-redundant system. From the example, we also describe the general transformation in terms of intuitively defined AADL semantics. Furthermore, we develop a static analysis checker to find necessary conditions that must be satisfied in order for the PALS transformation to work correctly. The transformations and static checks that we have described are implemented in OSATE using the generated EMF metamodel API for model manipulation.