Software Engineering Institute

The emerging Society of Automotive Engineers Architecture Analysis and Design Language (AADL) standard is an architecture modeling language for real-time, fault-tolerant, scalable, embedded, multiprocessor systems. It enables the development and predictable integration of highly evolvable systems as well as analysis of existing systems. It supports early and repeated analyses of a system's architecture with respect to performance-critical properties through an extendable notation, a tool framework, and precisely defined semantics. This report discusses the role and benefits of using the AADL in the process of analyzing an existing avionics system. The AADL is used to describe architecture patterns in the system being analyzed and to identify potentially systemic issues in the system. Findings related to timing, scheduling, and fault tolerance and the benefits of the use of the AADL are examined. 

The report also highlights the benefits of working with architecture abstractions that are reflected in the AADL notation, in particular the separation of architecture design decisions from implementation decisions. Such a lightweight architecture analysis is typically followed by a full-scale AADL model of the system with required and actual timing, performance, and reliability figures, and its analysis to determine whether the requirements are met.