1. Introduction to Architecture Session Marseilles September 1999
John Harvey
CERN / LHCb

2. Importance of Software Architecture
Booch : “Development of complex software systems should be architecture-driven”
Architecture specifications provide a blueprint for everyone to follow
facilitate communication between developers
developers know how to contribute their pieces
Architectures can be designed to accommodate new requirements or changes in technology
adaptable - more resilient to change
flexible and extensible - they must evolve in an incremental fashion
Implemented via frameworks that can be reused for different data processing applications
ensure architecture is respected
solve standard computing tasks once….must do a lot and be configurable
provide clean interface for end user - must be easy to understand and use

3. Goals of Architecture Session
Raise awareness of the importance of firstly specifying the software architecture before building large software systems
Introduce the vocabulary explaining the meaning of commonly used terms
Introduce through examples common architectural patterns (styles)
Illustrate the important architectural features that have impact on quality
Introduce through examples architectures in use in HEP today
Illustrate the scope of the architecture
conceptual view illustrating logical structure
concrete view illustrating the physical structure (packaging, building releases, impact on performance…)
Exchange opinions on what constitutes a good architecture
as our data processing needs are so similar a good architecture for one experiment should be applicable elsewhere
Identify important issues that need to be addressed and concrete actions that should be taken

4. The goals of the session are not to…..
Solve technical issues
Choose the best technical solution
Scope does not cover very specific application domains such as the data acquisition system

5. Architecture Study Group
Setup end June 1999 as a technical forum to study the issue of software architecture ..
.. and to help prepare for this workshop
Membership :
Alberto Aimar, John Apostolakis, Rene Brun, Dirk Duellmann, John Harvey, Vincenzo Innocente, Pere Mato, RD Schaffer, David Stickland, Lassi Tuura
Christian Arnault, Federico Carminati, Fons Rademacker, Craig Tull, Pierre vande Vyvre
Met seven times during the summer - informal
Results of deliberations kept on a web site
copies of slides and bibliography of relevant published material and web sites
URL :
Interest to continue after the workshop
come back to in the discussion