Abstract. Model Driven Engineering (MDE) received a lot of attention in the last years, both from academia and industry. However, there is still a debate on which basic concepts form the foundation of MDE. The Model Driven Architecture (MDA) from the OMG does not provided clear answers to this question. This standard instead provides a complex set of interdependent technologies. This paper is the first of a series aiming at defining the foundations of MDE independently from a particular technology. A megamodel is introduced in this paper and incrementally refined in further papers from the series. This paper is devoted to a single concept, the concept of model, and to a single relation, the RepresentationOf relation. The lack of strong foundations for the MDA ’ 4-layers meta-pyramid leads to a common mockery: "So, MDA is just about Egyptology?!". This paper is the pilot of the series called "From Ancient Egypt to Model Driven Engineering". The various episodes of this series show that Egyptology is actually a good model to study MDE. 1

these concepts related? It is striking to see that, though MDE is supposed to be about precise modelling, MDE core concepts are usually described in natural language or at best, using sketchy "à-la " UML diagrams. These diagrams are very often inconsistent and too vague to reason about. Most of the time, they are neither validated, not even used by their authors. When precise descriptions are provided, it is only to describe a

Abstract. Despite the recent interest for Model Driven Engineering approaches, the so-called four-layers metamodelling architecture is subject to a lot of debate. The relationship that exists between a model and a metamodel is often called instanceOf, but this terminology, which comes directly from the object oriented technology, is not appropriate for the modelling of similar meta-pyramids in other domains. The goal of this paper is to study which are the foundations of the meta-pyramids independently from a particular technology. This paper is actually the second episode of the series "From Ancient Egypt to Model Driven Engineering". In the pilot episode, the notion of megamodel was introduced to model essential Model Driven Engineering concepts. The notion of models was thoroughly discussed and only one association, namely RepresentationOf was introduced. In this paper the megamodel is extended with one fundamental relation in order to model the notion of languages and of metamodels. It is shown how Thotus the Baboon helped Nivizeb the priest in designing strong foundations for meta-pyramids. The secrets of some ancient pyramids are revealed. 1

Software evolution-in-the-large is a challenging issue. While most research work concentrates on the evolution of "programs", large scale software evolution should be driven by much higher levels of abstraction. Software architecture is an example of such abstraction. The notion of co-evolution between architecture and implementation has been identified and studied recently. This paper claims that other abstraction dimensions should also be taken into account, leading to what we call the 3D software space. This conceptual framework is used to reason about evolution-in-the-large phenomena occurring in industry. The meta dimension, which constitutes the core of the MDA approach, is considered as fundamental. This paper makes the distinction between appliware and metaware and put the lights on meta-model and model co-evolution. Conversely to the MDA approach which makes the implicit assumption that meta-models are neat, stable and standardized, in this paper meta-models are considered as complex evolving software artefacts that are most often recovered from existing metaware tools rather than engineered from scratch. In fact, we identified the notion of meta-model and model co-evolution in the context of the evolution of a multimillion LOC component-based software developed by one of the largest software companies in Europe.

Tool adoption is a major issue in software engineering. In the last decades many ideas and tools have been developed in laboratories but only a few of them had a direct impact on software industry. This paper presents the results of a ten-years collaboration between the LSR-IMAG laboratory and Dassault Systmes, one of the major software companies in Europe. Two scenarii in tool adoption are described. The first one describes the successful adoption of a configuration management tool, the second one describes issues in deploying reverse architecting tool in the company.