2. ARCHITECTURE ANALYSIS & DESIGN LANGUAGE (AADL) AS5506
This Architecture Analysis & Design Language (AADL) standard document was prepared by the SAE AS-2C Architecture Description Language Subcommittee, Embedded Computing Systems Committee, Aerospace Avionics Systems Division.  This subcommittee is chaired by Bruce Lewis (bruce.a.lewis@us.army.mil +1-256-876-3224), US Army Aviation and Missile Command (AMCOM) Software Engineering Directorate (SED), Acquisition Technology Division.
The starting point for the AADL standard development was MetaH, an architecture description language and non-commercialized supporting toolset, developed at Honeywell Technology Laboratories under the sponsorship of the US Defense Advanced Research Projects Agency (DARPA) and US Army Aviation and Missile Command (AMCOM).


Foreword
This standard was prepared by the Society of Automotive Engineers (SAE) Avionics Systems Division (ASD) Embedded Computing Systems Committee (AS-2) Architecture Description Language (AS-2C) subcommittee.
This standard addresses the requirements defined in SAE ARD 5296, Requirements for the Avionics Architecture Description Language. 
The starting point for the AADL standard development was MetaH, an architecture description language and supporting toolset, developed at Honeywell Technology Laboratories under DARPA and Army AMCOM sponsorship. 
The AADL standard has been designed to be compatible with real-time operating system standards such as POSIX and ARINC 653.
The AADL standard provides explicit support for extensions to the core language through the property extension mechanism for defining and integrating new properties and property sets. It also includes annex subclauses for the definition and integration of complementary sublanguages. 
The AADL standard is aligned with Object Management Group (OMG) Unified Modeling Language (UML) through profiles for AADL as defined in the annexes. 
The AADL standard includes a specification of an AADL-specific XML interchange format.
The AADL standard provides guidelines for users to transition between AADL models and program source text written in Ada 95 (ISO/IEC 8652/1995 (E)) and  C (ISO/IEC 9899:1999).
Introduction
The SAE Architecture Analysis & Design Language (referred to in this document as AADL) is a textual and graphical language used to design and analyze the software and hardware architecture of performance-critical real-time systems.  These are systems whose operation strongly depends on meeting non-functional system requirements such as reliability, availability, timing, responsiveness, throughput, safety, and security.  The AADL is used to describe the structure of such systems as an assembly of software components mapped onto an execution platform.  It can be used to describe functional interfaces to components (such as data inputs and outputs) and performance-critical aspects of components (such as timing).  The AADL can also be used to describe how components interact, such as how data inputs and outputs are connected or how application software components are allocated to execution platform components.  The language can also be used to describe the dynamic behavior of the runtime architecture by providing support to model operational modes and mode transitions.  The language is designed to be extensible to accommodate analyses of the runtime architectures that the core language does not completely support.  Extensions can take the form of new properties and analysis specific notations that can be associated with components.
The AADL was developed to meet the special needs of performance-critical real-time systems, including embedded real-time systems such as avionics, automotive electronics, or robotics systems.  The language can describe important performance-critical aspects such as timing requirements, fault and error behaviors, time and space partitioning, and safety and certification properties. Such a description allows a system designer to perform analyses of the composed components and systems such as system schedulability, sizing analysis, and safety analysis. From these analyses, the designer can evaluate architectural tradeoffs and changes. 
Since the AADL supports multiple and extensible analysis approaches, it provides the ability to analyze the cross cutting impacts of change in the architecture in one specification using a variety of analysis tools.  The AADL specification language is designed to be used with analysis tools that support the automatic generation of the source code needed to integrate the system components and build a system executive.  Since the models and the architecture specification drive the design and implementation, they can be maintained to permit model driven architecture based changes throughout the system lifecycle.
Information and Feedback
The website at http://www.aadl.info is an information source regarding the SAE AADL standard. It makes available papers on the AADL, its benefits, and its use. Also available are papers on MetaH, the technology that demonstrated the practicality of a model-based system engineering approach based on architecture description languages for embedded real-time systems.
The website provides links to three SAE AADL related discussion forums:
    • The SAE AADL User Forum to ask questions and share experiences about modeling with SAE AADL,
    • The AADL Toolset User Forum to ask questions and share experiences with the AADL Open Source Toolset Environment, and
    • The SAE Standard Document Corrections & Improvements Forum that records errata, corrections, and improvements to the current release of the SAE AADL standard.
The website provides information and a download site for the Open Source AADL Tool Environment.  It also provides links to other resources regarding the AADL standard and its use. 
Questions and inquiries regarding working versions of annexes and future versions of the standard can be addressed to info@aadl.info.
Informal comments on this standard may be sent via e-mail to errata@aadl.info. If appropriate, the defect correction procedure will be initiated. Comments should use the following format:
          !topic Title summarizing comment
          !reference AADL-ss.ss(pp)
          !from Author Name yy-mm-dd
          !keywords keywords related to topic
          !discussion
          text of discussion
where ss.ss is the section, clause or subclause number, pp is the paragraph or line number where applicable, and yy-mm-dd is the date the comment was sent. The date is optional, as is the !keywords line.
Multiple comments per e-mail message are acceptable. Please use a descriptive “Subject” in your e-mail message.
When correcting typographical errors or making minor wording suggestions, please put the correction directly as the topic of the comment; use square brackets [ ] to indicate text to be omitted and curly braces { } to indicate text to be added, and provide enough context to make the nature of the suggestion self-evident or put additional information in the body of the comment, for example:
          !topic [c]{C}haracter
          !topic it[']s meaning is not defined
Architecture Analysis & Design Language (AADL) Standard Document