Allied Standards Avionics Architecture Council

Allied Standards Avionics Architecture Council, or ASAAC, is an effort to define and validate a set of Open Architecture Standards for Avionics Architecture, particularly in the field of Integrated Modular Avionics.

ASAAC is managed by the UK Ministry of Defence, and many major European Avionics companies participate in the Working group, such as:
* BAE Systems
* GE Aviation Systems (formerly Smiths Aerospace)
* Dassault Aviation
* Thales Group
* EADS
* ESG Elektroniksystem- und Logistik-GmbH

History

The ASAAC project was divided into two phases:
* The first phase was an exploratory phase of the IMA concept.
* The second phase was the elaboration of draft standards. The development was completed in May 2004.
* Next was a demonstration phase, and the publication of a POSIX-based open-source version of the standard

ASAAC initially published provisional standards under the name of Def Stan:
* Def Stan 00 74 [cite web
url=http://www.dstan.mod.uk/data/00/074/01000100.pdf
title=ASAAC Standards Part I - Proposed Standard on Software
publisher=www.assconline.co.uk
accessdate=2008-07-26] : Proposed Standards for Software
* Def Stan 00 75: Proposed Standards for Communications/Networks
* Def Stan 00 76: Proposed Standards for Common Functional Modules
* Def Stan 00 77: Proposed Standards for Packaging
* Def Stan 00 78: Proposed Standards for Architecture

All standards but "Def Stan 00 74" have been withdrawn in July 2007, the MOD and representatives from the Working group considering that it was the only standard "bearing any influence".

Proposed Standards for Software (Def Stan 00 74)

"Def Stan 00 74" is defined in the context of Integrated Modular Avionics. Software components are located on modulescite web
url=http://www-users.cs.york.ac.uk/~mark/papers/ISSC2006.pdf
title=Flexibility and Manageability of IMS Projects
publisher=University of York
accessdate=2008-07-27] .

* Configuration and initialization: The configuration is considered as defined in a series of blueprints describing thread and process allocation, virtual communication channels... However, the standard does not define precisely the grammar or the language of these blueprints. As for initialization, there is no specific API to allow initialization by the low-level Real-time operating system (RTOS) services.
* Access to Datas is abstracted from its actual physical storage.

Links to ARINC 653 and POSIX

The field covered by ASAAC in "Def Stan 00 74" is similar to ARINC 653 (ARINC 653 is a software specification for space and time partitioning in avionics). However, there are differences between the two standards: Some features of ASAAC API, such as file handling, thread managing inside process, or debugging, are not considered in ARINC 653.

However, for the part where the two standards overlap, it is often possible to translate ASAAC interfaces in ARINC 653 API calls (and even in POSIX calls). Approximately 30% of the ASAAC API is covered directly by ARINC 653 and POSIXcite web
url=http://www.assconline.co.uk/asaac/An_Overview_of_the_ASAAC_Standards.ppt
title=An Overview of the ASAAC Standards
publisher=assonline.co.uk
accessdate=2008-08-02] .

For example, the following call defined in ASAAC: receiveBufferwould be translated in ARINC 653 by: RECEIVE_BUFFER()and also in POSIX by: recv()

Links to STANAG 4626

STANAG 4626 is a NATO standardization of the requirements defined by the ASAAC program, proposed by the MOD and the ASAAC Working group.

ee also

* Integrated Modular Avionics
* ARINC 653
* STANAG 4626

References

External links

* [http://www.assconline.co.uk/asaac.asp ASAAC homepage]
* [http://193.116.28.245/documents/BS_Slides-Systems_WG_200705.pdf Presentation of ASAAC Working Group]
* [http://sourceforge.net/projects/asaac-openos/?abmode=1 Open Source OS adaption layer for STANAG 4626]