Monday, October 26, 2009

Lack of process view of automotive software

When discussing an architectural problem with my colleagues we identified that an initialisation/activation mechanism could be defined either as a method used between logical components or as an initialisation between run-time processes. But we could not propose the second mechanism since it would be impossible to communicate to the developers.

The reason for this is that we are not using a process view at Volvo (or at any other OEM that I have worked with either). With process view I mean the view as defined in the 4+1 paper by P. Kruchten. And I have not seen any other viewpoint used here that would fulfil a similar purpose.
This has some interesting implications:
  • The deployment of functionality is in Kruchten's paper done by assigning logical components to processes and the deploying the processes onto the physical view. Among OEMs the deployment relationship is directly between static logical components and the hardware (i.e. ECUs). So there is no possibility to express concepts as "concurrency", "precedes" or "is activated by".
  • It must be the responsibility of the ECU suppliers to define the process view of their ECU. And to be honest I have no idea if they do since this is not requested nor followed up by OEMs...
  • The fundamental building block in AUTOSAR is the software component (SW-C), which can be called a static logical component if one is not too much of perfectionist with meta-models. The SW-C contains runnable entities which is the entity that is scheduled. But also in AUTOSAR it is the SW-C and not the runnable entities that are deployed to ECUs. I think this is driven by the first item above...
  • Since it is the static SW-C that has the explicit relationship to other ECUs through the defined port and interface mechanisms in AUTOSAR there is no possibility to define a "dynamic" mechanism to "activate", "run simultaneously" or something similar usually defined in a process view (or process architecture).
I was thinking of writing a short paper elaborating on this and relating it to some research papers, but I probably will not. First it is not directly in line with the subject of my thesis. Second there are more pressing things to do. So if anybody else wants to pursue this I would be glad to be a co-author, discussion partner ot at least get mentioned in the acknowledgements.

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