Allied Standards Avionics Architecture Council
Encyclopedia
Allied Standards Avionics Architecture Council, or ASAAC, is an effort to define and validate a set of Open Architecture Standards for Avionics
Avionics
Avionics are electronic systems used on aircraft, artificial satellites and spacecraft.Avionic systems include communications, navigation, the display and management of multiple systems and the hundreds of systems that are fitted to aircraft to meet individual roles...

 Architecture, particularly in the field of Integrated Modular Avionics
Integrated Modular Avionics
Integrated modular avionics represent real-time computer network airborne systems. This network consists of a number of computing modules capable of supporting numerous applications of differing criticality levels....

.

ASAAC is managed by the UK Ministry of Defence
Ministry of Defence (United Kingdom)
The Ministry of Defence is the United Kingdom government department responsible for implementation of government defence policy and is the headquarters of the British Armed Forces....

, and many major European Avionics companies participate in the Working group
Working group
A working group is an interdisciplinary collaboration of researchers working on new research activities that would be difficult to develop under traditional funding mechanisms . The lifespan of the WG can last anywhere between a few months and several years...

, such as:
  • BAE Systems
    BAE Systems
    BAE Systems plc is a British multinational defence, security and aerospace company headquartered in London, United Kingdom, that has global interests, particularly in North America through its subsidiary BAE Systems Inc. BAE is among the world's largest military contractors; in 2009 it was the...

  • GE Aviation Systems (formerly Smiths Aerospace)
  • Dassault Aviation
    Dassault Aviation
    Dassault Aviation is a French aircraft manufacturer of military, regional and business jets, a subsidiary of Dassault Group.It was founded in 1930 by Marcel Bloch as Société des Avions Marcel Bloch or "MB". After World War II, Marcel Bloch changed his name to Marcel Dassault, and the name of the...

  • Thales Group
    Thales Group
    The Thales Group is a French electronics company delivering information systems and services for the aerospace, defense, transportation and security markets...

  • EADS
    EADS
    The European Aeronautic Defence and Space Company N.V. is a global pan-European aerospace and defence corporation and a leading defence and military contractor worldwide...

  • ESG Elektroniksystem- und Logistik-GmbH
    Elektroniksystem- und Logistik-GmbH
    ESG is a limited liability company founded in 1967 in Munich. Shareholder partners in the firm are EADS, Rohde & Schwarz, Thales, and Litef. The company, headquartered in a Munich suburb, has offices in Germany, France, USA and China...


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
    POSIX
    POSIX , an acronym for "Portable Operating System Interface", is a family of standards specified by the IEEE for maintaining compatibility between operating systems...

    -based open-source version of the standard


The current ASAAC standard has two parts:
  • Def Stan 00-74: ASAAC Standards Part 1: Standards for Software
  • Def Stan 00-74: ASAAC Standards Part 2: Rationale Report for Software Standards


ASAAC initially published provisional standards in five parts in January 2005:
  • Def Stan 00-74: 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 but Def Stan 00-74 were withdrawn in July 2007, the MOD
Ministry of Defence (United Kingdom)
The Ministry of Defence is the United Kingdom government department responsible for implementation of government defence policy and is the headquarters of the British Armed Forces....

 and representatives from the Working group
Working group
A working group is an interdisciplinary collaboration of researchers working on new research activities that would be difficult to develop under traditional funding mechanisms . The lifespan of the WG can last anywhere between a few months and several years...

 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
Integrated Modular Avionics
Integrated modular avionics represent real-time computer network airborne systems. This network consists of a number of computing modules capable of supporting numerous applications of differing criticality levels....

. Software components are located on modules.
  • Configuration and initialization: The configuration is considered as defined in a series of blueprints
    Configuration file
    In computing, configuration files, or config files configure the initial settings for some computer programs. They are used for user applications, server processes and operating system settings. The files are often written in ASCII and line-oriented, with lines terminated by a newline or carriage...

     describing thread
    Thread (computer science)
    In computer science, a thread of execution is the smallest unit of processing that can be scheduled by an operating system. The implementation of threads and processes differs from one operating system to another, but in most cases, a thread is contained inside a process...

     and process
    Process (computing)
    In computing, a process is an instance of a computer program that is being executed. It contains the program code and its current activity. Depending on the operating system , a process may be made up of multiple threads of execution that execute instructions concurrently.A computer program is a...

     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)
    Real-time operating system
    A real-time operating system is an operating system intended to serve real-time application requests.A key characteristic of a RTOS is the level of its consistency concerning the amount of time it takes to accept and complete an application's task; the variability is jitter...

     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
ARINC 653 is a software specification for space and time partitioning in Safety-critical avionics Real-time operating systems...

 (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
Application programming interface
An application programming interface is a source code based specification intended to be used as an interface by software components to communicate with each other...

, such as file handling
Computer file
A computer file is a block of arbitrary information, or resource for storing information, which is available to a computer program and is usually based on some kind of durable storage. A file is durable in the sense that it remains available for programs to use after the current program has finished...

, thread
Thread (computer science)
In computer science, a thread of execution is the smallest unit of processing that can be scheduled by an operating system. The implementation of threads and processes differs from one operating system to another, but in most cases, a thread is contained inside a process...

 managing inside process
Process (computing)
In computing, a process is an instance of a computer program that is being executed. It contains the program code and its current activity. Depending on the operating system , a process may be made up of multiple threads of execution that execute instructions concurrently.A computer program is a...

, or debugging
Debugging
Debugging is a methodical process of finding and reducing the number of bugs, or defects, in a computer program or a piece of electronic hardware, thus making it behave as expected. Debugging tends to be harder when various subsystems are tightly coupled, as changes in one may cause bugs to emerge...

, 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
POSIX
POSIX , an acronym for "Portable Operating System Interface", is a family of standards specified by the IEEE for maintaining compatibility between operating systems...

 calls). Approximately 30% of the ASAAC API is covered directly by ARINC 653 and POSIX.

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

Links to STANAG 4626

STANAG 4626
STANAG 4626
STANAG 4626 is a NATO standard which define a set of Open Architecture Standards for Avionics Architecture, particularly in the field of Integrated Modular Avionics...

 is a NATO standardization of the requirements defined by the ASAAC program, proposed by the MOD
Ministry of Defence (United Kingdom)
The Ministry of Defence is the United Kingdom government department responsible for implementation of government defence policy and is the headquarters of the British Armed Forces....

 and the ASAAC Working group
Working group
A working group is an interdisciplinary collaboration of researchers working on new research activities that would be difficult to develop under traditional funding mechanisms . The lifespan of the WG can last anywhere between a few months and several years...

.

External links

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