Boris Lublinsky posted a good overview on InfoQ about the online discussions around BPMN 2.0 and it reveals IMO a very profound problem in traditional BPM thinking.
One group wants to give the graphical process modelling notation executable semantics. In that case, a BPMN 2.0 diagram would specify exact (and hopefully portable) semantics and it can be executed on a computer system. On the other hand, some people raise concerns about the simplicity in that approach.
This again shows that today the dual nature of BPM is not enough recognized by BPM vendors. BPM tries to make the bridge between non technical business analysts and the implementation of a business process.
A business process analyis can contain a diagram and it expresses how people and systems work together. Such an analysis is targetted at other people so it can include free text and a diagram. It's description of how things work in the real world. Analysis can be done without even automation. An analysis is always an important input to express the requirements for the automation of a business process. Some analysts use very expressive diagram notations, while others just use boxes and arrows. But even in case a lot of details are expressed in the diagram, they are not necessarily expressing runtime execution semantics in the software sense of the word.
In case a business process is automated with a Business Process Management System (BPMS) , an executable process needs to be created. An executable process serves as input to a BPMS, after which it will be able to execute the process. Executing a process by a BPMS means a combination of monitoring progress and performing automated tasks. Executable processes can also be based around a diagram. But in this case, the diagram is a projection of a software artifact. The executable process will in most cases contain technical details outside the scope of the diagram. Whatever way you look at it, an executable process is software.
There are some aspects that cause some fog around this clear picture. In practice, it turns out that the roles are not that clearly separated. In fact, a lot of business analysts have technical knowledge so they already are able to think in terms of what it means to execute the software. Also, there are different levels of process languages. The more a executable process language targets to be general purpose, the more complex it will be and the more technical it will become.
If a diagram notation (like BPMN) wants to be used for both the analysis as well as the executable process diagram, it should limit the number of details that can be expressed. As analysis details don't match with technical details necessary for making the process executable. The more details that are exposed in the graphical notation, the conflicts will arise because of this dual nature of the process diagram.
More and more vendors start to see that the gap between the analysis process and the executable process can not just be eliminated. But still quite a few target round tripping, which means that the analysis model is kept in sync with the executable model. I have seen multiple vendors come out with features that support this. Still I think that is a waiste of time. Building tools that synchronize automagically between the analysis and the executable diagram is too hard. Using those tools effectively will only succeed in environments with a lot of discipline cause changes in the executable process will often require an analyst to incorporate those changes into the analysis diagram. Furthermore, those tools impose too much assumptions on the analysis language and the executable process language. FWIW, such an approach never did fly with UML Class Diagrams, and I don't see how the situation is different for processes. In fact, in case of UML class diagrams, no-one even thought of automagically synchronizing the analysis class model with the executable classes.
Instead, I think it is much more practical to create an executable process language that can build the executable details around a given diagram structure. That way, the executable process diagram will be very similar to the analysis diagram. The better the executable process, the less the diagram will have to change. But a conversion step cannot just be eliminated. Even if the executable process languages was 'perfect' in keeping the same diagram, some parts in the analysis diagram might not even be automated.
Once a business process gets automated, the diagram in the analysis document can be replaced with the executable process diagram. This has as a consequence that the analysis diagram becomes read-only for the analysts once it has been converted to an executable process.
Instead of embracing the dual nature of BPM, the InfoQ post outlines very well how two opposite camps have formed around analysis and implementation. Previously the focus of BPMN was on analysis only. It's much easier to reach consensus in that more limited scope. Now, the big vendors got involved and expressed a clear vision to make BPMN executable. That opens up the whole discussion of the environment. BPEL clearly chose for an ESB environment based on WSDL. But (just to give another example) jPDL is defined in a Java environment. I don't yet see how you can define an executable process language without selecting a concrete environment in which it operates. This is exactly why we support multiple process languages on our Process Virtual Machine.
The way things are moving now, the move towards executability of BPMN is starting to become clear. But looking further in that direction, I can only see quicksand. As indicated above, the vision of making BPMN executable could quickly be dragged down by many technical "details". It will be interesting to see how that is going to play out, but my fear is that it's not gonna be a smooth ride.
One thing puzzles me, though. Why is everyone talking about a new file format for BPMN 2.0, while there is XPDL ? The WfMC guys did a lot of effort to get XPDL synced up with BPMN and they made a lot of noise about it, so it cannot be an oversight. Still everyone seems to be silent about the possibility of using XPDL as the file format. Does anyone know more about the motivations for this silence ?