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Distribution and Reusability of Ada Real-Time Applications through Graceful and On-Line Operations

Objective

The objective of DRAGON was to develop methods and provide tools for designing reusable software for distributed real-time applications of a long-lived nature (such as flexible manufacturing systems and space application systems).
Criteria for structuring systems in terms of reusable, target-independent Ada components were investigated in two aspects: formal specifications of module interfaces and operations, and support for distribution and target computer and plant configuration management.
Changes in target architecture and plant dimension and parameters are a major cause of unanticipated software changes, making software hard to reuse: this issue was addressed in the project by structuring the program as distributable units that were completely insensitive to target characteristics.
Provisions for reconfiguration, task migration and modification in non-stop mode require careful analysis of the Ada tasking system: the intended approach was to start from existing formalisations of Ada semantics and then extend them. Reusability was obtained by assembling components and tailoring highly generic ones. A database library of existing components was to be designed.
The objective was to develop methods and provide tools for designing resusable software for distributed real timme applications of a long lived nature (such as flexible manufacturing systems and space application systems). Criteria for structuring systems in terms of reusable, target independent Ada components were investigated in 2 aspects: formal specifications of module interfaces and operations, and support for distribution and target computer and plant configuration management. Changes in target architecture and plant dimension and parameters are a major cause of unanticipated software changes, making software hard to reuse: this issue was addressed in the project by structuring the program as distributable units that were completely insensitive to target characteristics. Provisions for reconfiguration, task migration and modification in nonstop mode require careful analysis of the Ada tasking system; the approach was to start from existing formalizations of Ada semantics and then extend them. Reusability was obtained by assembling components and tailoring highly generic ones. A database library of existing components was designed. The object oriented language DRAGOON was developed, along with a specification of its formal semantics. Preprocessing tools were developed to support the translation of DRAGOON into Ada. Run time support has been provided by the dragoon distributive executive (DDX), which handles interprocess communication between components, dynamic loading of components, and dynamic reconfiguration. The DEMON design method for reusable software was produced. There is a toolset which supports DRAGOON and the DEMON design method. Formal methods work investigated algebraic specification techniques in object oriented environments. The industrial enhancement of a maritime surveillance system was used as a test of the methods and tools developed.
The object-oriented language DRAGOON was developed, along with a specification of its formal semantics. It is like Ada, but its classes incorporate much richer constructs for describing data and methods (including concurrency).
Preprocessing tools were developed to support the translation of DRAGOON into Ada.
Run-time support has been provided by the Dragoon Distributive eXecutive (DDX), which handles inter-process communication between components, dynamic loading of components, and dynamic reconfiguration.
The DEMON design method for reusable software was produced. It is used with a formal specification such as object-oriented Z, and copes with concurrency and distribution. There is a toolset (eg structure editor) which supports DRAGOON and the DEMON designmethod.
Formal methods work investigated algebraic specification techniques in object-oriented environments.
The industrial enhancement of a maritime surveillance system was used as a test of the methods and tools developed in DRAGON. An object-oriented approach was followed.
Exploitation
The project will contribute to the industrial use of Ada and will advance industrial understanding of the problems and opportunities of software reuse.

Coordinator

TXT Ingegneria Informatica SpA
Address
Via Socrate 41
20128 Milano
Italy

Participants (4)

DORNIER SYSTEM GMBH
Germany
Address
An Der Bundesstraße 31
88039 Friedrichshafen
GSI TECSI Software SA
France
Address
6 Cours Michelet
92064 Paris La Défense
UNIVERSITY COLLEGE OF WALES ABERYSTWYTH
United Kingdom
Address
Penglais Campus, Cerediglon
SY23 3BZ Aberystwyth
University of Lancaster
United Kingdom
Address
Bailrigg
LA1 4YW Lancaster