ASSC and C

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ASSC and C
Clive Lee

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ASSC Mission Objective

• To enhance and exploit the role which standards
  play in the development and use of avionic
  systems, to the advantage of the MoD and it
  commercial suppliers

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Role of the ASSC

• The ASSC will endeavour to
• provide expert advice on the application of
  existing standards and technologies
• provide clarification of opinion on the technical
  content of proposed national and international
  avionics standards
• influence the standardisation processes, for the
  good of the MoD and it suppliers, and the
  avionics industry as a whole
• encourage the harmonisation of military and civil
  approaches to the definition and use of avionics
  standards
• promote knowledge transfer and closer working
  relationships between the civil and military
  sectors.

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ASSC and Software Technology

• Over the years, ASSC has increased its effort to
  aid the exploitation of software technology in
  avionic systems.

• Example Projects
• Real Time Operating Systems for Avionic Systems
• Technical Guidance for selection of RTOSs
• Allied Standard Avionics Architecture Council
  (ASAAC)
• Software considerations in Integrated Modular
  Architectures
• Guidance to Configure logic of complex
  electronic hardware to provide avionic functions
  e.g. CPLD, FPGAs

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Object Oriented Software Technology

• Collection of S/w Design and Programming
  Techniques
• Mature technology with basic ideas and techniques
  with Thirty/Forty Years history
• Success in Commercial Environment in last 25
  Years
• Success in standardisation of UML in 1990
• OO Languages inc. Smalltalk, C, Java, Ada
  2005(?)

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Object Oriented Software in Avionics

• OO Software Processes have been introduced, used
  and accepted for over 10 years in military
  avionics by the major developers such as BAE
  Systems, but not for High Integrity projects.
• Slow Progress made towards High Integrity
  acceptance
• NASA produced OOTiA (OO Techniques in Aviation)
  2004
• NASA collected over 100 technical concerns (not
  addressed)
• DO-178C has group looking at OO Techniques.
• Many High Integrity projects have rejected the
  use of OO technology because of the perceived
  risks in certification

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Programming Language Selection

• A major issue in any High Integrity software
  development is the selection of the programming
  language and the argument that the coding process
  has not introduced any errors e.g. due to
  insecurities or ambiguities in the language.
• The motivation behind the ASSC support for the
  C project is to extend the use OO technology
  into High Integrity projects by providing rule to
  support the use of an OO language.
• The reason for the choice of C is shown on
  following slide rotated.

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Languages
An Empirical Study of Programming Language
Trends, Software , May/June 2005
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Object Oriented Issues

• Java has only started to be used in real-time and
  safety related applications Aonix has just
  released its first safety critical Java but doe
  not expect significant sales for 5 years
• Java aside C is the most widely used language
  claiming to be an object oriented programming
  language.

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Summary

• ASSC supports avionics systems
• It has increasingly supported software technology
• The benefits of Object Oriented software
  technology have not been realised in safety
  critical developments
• The inability to justify of the use of a suitable
  language has restricted the application of Object
  Oriented software technology in these
  developments
• The C project may provide an acceptable
  argument for the use of C.