25 May 2011

Architectural views in practice

My research is not really focused on identifying the “best” architectural views for in-vehicle software. But as a side effect to the studies I am presently doing I got to think about three views that could actually make a difference in how well large projects succeeds (or fails). I have thought about the need of addiitonal views, but cannot think of an immediate need of more.

Integration is always an in issue in large projects that has some form of iterative development. With the increasing inter-dependencies between various parts of the system it is almost impossible to know what should be integrated when, for example what can actually be tested. There actually is already an architectural view defined that addresses this concern, the anatomy. I would describe the anatomy as visualisation of the complete system seen from an integration perspective, for example if a feature depends on a MOST interface it is no use to test it if the interface is not implemented. The visual picture means everybody should have the same understanding of the “.
The anatomy should dictate the order of development, delivery schedules and integration order. And the progress should be measured in how much of the anatomy is implemented, not in customer features. There is a relationship between customer features and the anatomy, but it is not one-to-one. you can read more about “Integration Centric Development and Anatomies” in a PowerPoint presentation or the article “Manifesting Shared Affordances in System Development – the System Anatomy” by L. Taxén and J. Lilliesköld.

The second view is the systems view, i.e. how the complete system is decomposed in smaller parts. I prefer to see this view as equivalent to the development view in Kruchten’s 4+1 views, i.e. it is aligned with the development teams. One can discuss if the system decomposition follows the organisation, as predicted by Conway’s law. The other extreme is that the development teams follow the most “logical” decomposition, i.e. ECUs, which is the most common unit to be outsourced to suppliers in the automotive domain.

The functional content of a vehicle is often defined by a list of customer features, which can be quite long, and this in itself can be considered an architectural view that concerns for example the business project, the marketing department and the end customer.
What is important for the development project is the relationship between this feature list and the two other views, i.e. what systems/development teams are responsible to implement the features and how the features relate to the anatomy. I don't know if these two relationships/mapping between views should be considered as separate views, which would make the total number of views 3+2.