Three years ago I posted about the lack of adoption and lack of tool interoperability for XMI:

The OMG has XMI versions 1.0, 1.1, 1.2 and 2.0, with 2.1 under development. Looking on Google, I note that there are 865 XMI files on the web using 1.0, 78 for 1.1, 64 for 1.2, and 34 for 2.0 (released in 2003). That gives some indication of the adoption of XMI as a format, and tallies with my own impression. Everybody was interested when it first came out, but most who actually tried to use it found it lacking. One can always hope the situation improves with newer versions...

So have things improved? In a word, no. Google finds 40 files for 2.1 (released in 2005), and the figures for 1.0 have dropped by over 90%. Now even the most used version, 1.2 from over five years ago, only has 136 files, and the figures decline from there. Yet still people I meet believe that XMI is a useful standard that will solve their problems.

What about tool interoperability then? In an article from the MODELS conference, Lundell et al. tested XMI with 14 UML tools. Obviously, the older tools can't load from the newer tools, but can the newer tools read models from the older tools? That's the important question after all, if you want to use XMI as insurance against your tool being discontinued: will this year's tools load last year's models? Here's the table, see the article for full details:

Looking at the tools supporting the latest version, 2.1, the picture looks darker still. None of these tools were able to import even 2.0. If XMI were really being implemented by these tools to offer interoperability and insurance, why would they drop support for the previous version? That leaves you rather open to claims that the intention is to pretend there is a standard, and then spread FUD by claiming that other tools don't support it. If the only tools that can interoperate are jointly developing the same code base (Eclipse, IBM, Borland), it's hardly impressive if their parallel versions work well together.

In the DSM world, of course, all this is somewhat academic: the tests were of the simplest possible UML Class Diagrams. None of the tools support working with DSM languages from another tool. If you want to move your DSM models from one tool to another, the main cost is the same as the cost of building support for that DSM language in the new tool -- translating the models is easy in comparison. In that area I'd say MetaEdit+ wins hands down: nothing comes close in terms of ease and speed for the metamodeler or features provided automatically for the modeler. But don't listen to me -- listen to our customers, industry gurus and even competitors all saying the same thing.