Case Studies
SUCCESS STORY - STOOD for software development within Airbus A340 program
The HOOD method and the STOOD development tool have been selected to various design software applications for the Airbus A340
- Embedded software: strategic systems software for A340 electrical flight control system (CDVE) and communication system (A.I.M.S.-F.A.N.S.).
- Code generators: dedicated application to process formalized system requirements in order to produce corresponding embedded software.
- Testing tools: software
applications running in test cabs including advanced user interfaces for some of them.
High level constraints
These developments must comply with civilian aviation recommendation specified by DO178-B/ED12-B (related to software for certification of flight systems and equipments), at the levels A, B and C (highest criticity). In addition, these applications need to be divided into several sub systems for which development may be sub-contracted, and for which development may be sub-contracted, and for which maintenance will have to be done for several decades.
Consequently, design method and relevant tool must enforce:
- A high level of quality for developed software
- The ability to perform long term maintenance
- A proper integration within an existing software development environment
- An appropriate answer to requirements from various application areas.
Benefits for development process
HOOD for static design : a HOOD design process brings support for the basic principles of Object-Oriented methods and also provides a more general modular approach, based on abstract data types (to keep the application architecture stable) and control flows (to represent task and task interactions defined during dynamic design step), instead of functions only. This abstraction principle, associated with the encapsulation mechanism, is an efficient way of securing data access, to masterize changes and to localize and measure the effect of these modifications. The modular breakdown principle leads to a hierarchy of abstraction levels,bringing a better understanding and localization of design information, and highlighting key elements at each level. All these principles can be ensured regardless of the implementation language.
HOOD for dynamic design : although HOOD4 handles dynamic properties, they are not precise enough to show the overall view of real time behaviour, in terms of graphical description and for an early validation of the architecture. Due to the fact that no “ standardized” method provides a complete solution to this problem, we use a home made customized method, that is not supported by a tool. Consistency between static and dynamic design representations needs to be achieved.
STOOD CASE Tool : Thanks to its code and documentation generators, its coherence checking tools, its user interface (that is user friendly but is still being improved) and its batch command files interface, STOOD can be easily included within a general purpose development environment framework.
Benefits for final realizations
The use of the HOOD method with STOOD as its supporting tool ensures that a proper quality of software development is
given for static design and coding tasks. We can positively state that regardless of the target language outputs of these tasks are coherent. The main software engineering principles are thus enforced.
The reactivity and availability of STOOD tool helped Aerospatiale to find efficient solutions to fit actual projects requirements. Improved by positive feedback from various development contexts, and by its customization capabilities, the STOOD tool is now part of the standard software environment framework for Aerospatialethat is recommended for all the developments.
Project summary
Projects: Ground and embedded software for Airbus A340
Customer : Aerospatiale Matra Airbus
Planning: 1989 to 20x0
Size: 150 000 lines of code
Development company: Aerospatiale Matra Airbus
Development platforms: Sun/Solaris, Vax/VMS and Windows/NT
Development team : 50 STOOD users
Technical choices :
Dynamic design : no tool
Static design : HOOD method and STOOD tool
Target Languages :
-Ada83 and Ada95 for 680x0 and Sun/Solaris targets
-C and assembler for Lynx
-OS/80486, Coldfire, 80x86, DSP targets
-Pascal, C++, and C for Windows 3.1 and NT targets
TNI-Valiosys
Email :
stood@tni-valiosys.com
Aerospatiale Matra Airbus
Mr Patrick Farail -Methods Development Engineer
Email : patrick.farail@airbus.aeromatra.com
Phone : +33 5 61 93 66 28 – Fax : +33 5 61 93 03 54
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