Connected Data Objects
Before getting started with CDO, the developer must convert their model to CDO. However, not all models can be converted to CDO native models – and some developers simply don't like to convert their models. If, for whatever reason, you cannot use a native CDO model, then you can activate legacy mode and use pure EMF objects with the CDO repository. The CDO team ask the developer to bear in mind that native mode is still recommended, to get the most out of CDO scalability and performance. The CDO team also report that the legacy mode is slower, in most cases, than native mode.
CDO legacy support is configurable, and turned off by default. For more information on running the legacy mode feature, please see Martin Fluegge's blog postj.