"Steve Mellor has long been active in this kind of work and has recently used the term Executable UML [Mellor and Balcer]. Executable UML is similar to MDA but uses slightly different terms. Similarly, you begin with a platform-independent model that is equivalent to MDA's PIM. However, the next step is to use a Model Compiler to turn that UML model into a deployable system in a single step; hence, there's no need for the PSM. As the term compiler suggests, this step is completely automatic."