Citing data from a 2005 report created by Venture Data Corp., Mellor, who has published extensively on UML and real-time operating systems, said that 14 percent of embedded systems projects used UML in 2004. The firm said in the report that it expected that number to grow to 25 percent by 2007.

"[Adoption] is lower than I would expect, and I am constantly surprised by that, because the benefits are in many ways very clear," Mellor said.

But, Mellor cautioned, these numbers are highly dependent on how UML users are defined.

"Are you a UML user if you sketch out a few diagrams on class diagrams or slate machines on the back of a beer mat?" Mellor asked.

Mellor said there are three different ways in which UML is used: as a sketching language, a blueprinting language to structure out the precise detail of how software is going to look, or "to describe the behavior of the system as a whole, and translate that into implementation."

The ability to sketch out an idea and communicate it, while not a very sophisticated use of UML, has value, Mellor said. But, he added, people see that as extra work because the model is not executed.

"Many people think of the UML as a sketching language or a blueprinting language, when in fact it can execute," Mellor said.

In order for UML adoption to increase, Mellor said, the industry must do a better job of communicating UML's uses and provide more tooling around the capability of using UML in execution.

"These tools take time to bring up," Mellor said, "and it takes time to bring these tools to market."

UML is a graphical and textual way to describe systems that has been standardized by the Object Management Group.

A full video clip of the interview with Stephen Mellor is available at http://www.eetimes.com/esc/.