The term software CAD suggests a design paradigm and supporting environment centering around wiring-diagram-like graphical representations of software structures which serve as a framework for both human reasoning and...
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The term software CAD suggests a design paradigm and supporting environment centering around wiring-diagram-like graphical representations of software structures which serve as a framework for both human reasoning and automated tools for analysis and code generation. The term revolutionary highlights the fact that adopting the approach in industry would have exactly that effect on the state of the practice. This paper has its roots in a research project at Carleton University, which developed an experimental software CAD environment called the Carleton embedded system design environment (CAEDE), oriented toward embedded systems and ada, to provide a demonstration of the concept and to serve as a research testbed. The major contribution of CAEDE presented in this paper is a demonstration of a visual paradigm which combines semantic depth and syntactic shallowness, relative to ada, in a manner that makes it possible for the embedded system designer to work in terms of abstract machines while still 'thinking ada.' A secondary contribution is the identification of Prolog as a promising approach for supporting tool development in an environment which supports the visual paradigm. We also describe experimental tools for temporal analysis, performance analysis, and the generation of skeleton ada code; however, details are left for future papers. [ABSTRACT FROM AUTHOR]
Distributed execution of a single program is becoming increasingly important for embedded real-time systems. The single program approach to distributed programming allows the advantages of language level software engi...
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Distributed execution of a single program is becoming increasingly important for embedded real-time systems. The single program approach to distributed programming allows the advantages of language level software engineering developments to be fully realized across machine boundaries. This paper examines some of the fundamental issues and tradeoffs involved in the translation and execution of programs written in the ada language and intended for distributed execution. The memory access architecture, binding time and degree of system homogeneity are the three basic dimensions in terms of which target systems can be described. Library subprograms and library packages are identified as natural distributable units of the language. The program to process/memory mapping and the unit of the language to be distributed are the key issues in the distribution of ada. The implications of various alternatives for these are analyzed. [ABSTRACT FROM AUTHOR]
Object-oriented design is a promising new approach for designing software systems to be implemented in ada. The object-oriented approach views a system as a set of objects, each object having a set of well defined ope...
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Object-oriented design is a promising new approach for designing software systems to be implemented in ada. The object-oriented approach views a system as a set of objects, each object having a set of well defined operations, and a transformation function that transforms the objects by performing operations on the objects. The current object-oriented design methodology proposed by Booch is strictly object-oriented, as it concentrates on identifying the objects and the operations on the objects and places little emphasis on the transformation function. This approach is acceptable for smaller systems, but may not be suitable for complex problems, where the transformation function may be fairly complex. For such systems the design methodology should explicitly address the design of the transformation function. In this paper, we propose an extended object-oriented design methodology, which incorporates a top-down, step-wise refinement approach in the object-oriented design methodology in a coherent fashion. The extended object-oriented design methodology also includes a phase of progressive object refinement to support the nesting of objects, that would allow entities in real life that are composed of other subentities to be modeled naturally in terms of nested objects. [ABSTRACT FROM AUTHOR]
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