Aligning the FACE and AADL Standards for System Development
A joint tooling and standardization endeavor between Adventium Labs and the Carnegie Mellon University (CMU) Software Engineering Institute (SEI) is making significant strides in aligning and accelerating combined use of the Future Airborne Capability Environment (FACE™) Technical Standard and the Architecture Analysis and Design Language (AADL). Adventium Labs wrote the AADL Annex for the FACE Technical Standard (https://www.sae.org/standards/content/as5506/4/) and the SEI validated the annex by automating translation from a FACE data model to AADL. The training video below shows the FACE Data Model to AADL Translator in action.
Adventium and the SEI both support the U.S. Army’s Joint Multi-Role (JMR) Mission System Architecture Demonstration (MSAD) Capstone program. “JMR MSAD has been a catalyst for tool maturation,” says Adventium’s Dr. Steve Vestal, “it allows us to put new analysis tools in the hands of users and get rapid, detailed feedback.”
This rapid feedback was critical to the success of the AADL Annex for the FACE Technical Standard, according to Adventium’s Tyler Smith who was the lead author of the document. “The SEI didn’t wait until the FACE annex was finalized to start working on tools. They started implementing the translator after we sent them our first draft. We worked closely with them, trading issue reports and recommendations so that when the FACE annex was approved by the standard committee in June of 2019, the tooling was already mature.”
Figure 1 FACE Technical Standard and AADL Overlap
The annex highlights the fact that the FACE and AADL are complimentary standards, as shown in Figure 1. Both standards came about in recent years due to new industry pressures for lower cost and early detection of problems.
AADL is a SAE International aerospace standard (AS) system model specification language (AS5506C) that supports various types of performance and safety analysis. The FACE Technical Standard defines a Reference Architecture intended for the development of portable software components targeted for general purpose, safety, and/or security purposes. The AADL Annex for the FACE Technical Standard Edition 3.0 (AS5506/4) provides guidelines for the integrated use of AADL and FACE Technical Standard data specifications and components.
The roots of AADL lie in the Defense Advanced Research Projects Agency (DARPA) Domain-Specific Software Architectures (DSSA) program. One of the results was an architecture description language for the domain of embedded computer systems called MetaH. MetaH evolved and solidified into the AADL international standard.
The FACE Technical Standard provides a means to describe Units of Conformance (UoCs) or Units of Portability (UoP) and the data they exchange. AADL provides the capability to model a cyber-physical system constructed from FACE UoCs and extended with hardware and operational properties. AADL supports modeling software structures such as data types and threads, hardware bindings, and environmental context to facilitate analysis of the interactions between system components in and between the hardware and software domains. AADL and the FACE Technical Standard overlap in their capacity to describe certain system features, but focus on different system characteristics and on highlighting different classes of errors. AADL is particularly good at detecting errors that only manifest in integrated computing systems. For example, AADL analyses can detect conditions like total memory exceeded, fully loaded processors fail to meet all deadlines, or unhandled error propagation flows.