Modern software development has to deal with many
different  aspects and different views of applications. Thus it
needs different  modelling notations and tools to support more and
more phases of the  entire development process. To ensure the
correctness of the models produced,  the tools need to integrate
sophisticated checkers, generators and  transformations. A feasible
approach to ensuring high quality of such add-ins  is to base them
on sound formal foundations. This paper summarizes our  research on
the Refinement of Component and Object Systems (rCOS)  and
illustrates it with experiences from the work on the Common  
Component Modelling Example (CoCoME). This gives evidence that 
the formal  techniques developed in rCOS can be integrated into a 
model-driven  development process and shows where it may be 
integrated in  computer-aided software engineering (CASE) tools 
for adding formally  supported checking, transformation and 
generation facilities.

Keywords: Formal methods, multi-view modelling,  rCOS, 
software design process, tool design, UML