  Implementing large software, as software analyzers which aim to be used in
industrial settings, requires a well-engineered software architecture in order
to ease its daily development and its maintenance process during its lifecycle.
If the analyzer is not only a single tool, but an open extensible collaborative
framework in which external developers may develop plug-ins collaborating with
each other, such a well designed architecture even becomes more important.
  In this experience report, we explain difficulties of developing and
maintaining open extensible collaborative analysis frameworks, through the
example of Frama-C, a platform dedicated to the analysis of code written in C.
We also present the new upcoming software architecture of Frama-C and how it
aims to solve some of these issues.
