Preface to the Second Edition

I have been both pleased and gratified by the success of the first edition of Real-Time UML: Developing Efficient Objects for Embedded Systems. I think the popularity of the first edition is due to both its timeliness and appropriateness of object technology (in general) and the UML (in particular) to the development of real-time and embedded systems. At the time of the publication of the first edition, it was clear that the UML would be a major force in the development of object-oriented systems. However, even its strongest supporters have been surprised by the rapidity and near totality of its acceptance by developers. As one methodologist supporting a different modeling approach expressed it to me, "I ignored the UML and then got hit with a freight train." The UML is wildly successful in the Darwinian sense of the term as well in its technical superiority and has become the most dominant life form in the object ecosphere.

As embedded systems gain in complexity, the old hack-and-ship approaches fail utterly and completely, and occasionally, spectacularly. The complexity of today's systems is driving developers to construct models of the system from different viewpoints, in order to understand and plan the various system aspects. These views include the physical or deployment view, and the logical, or essential, view. Both views must support structural and behavioral aspects. This is what the UML is about and this is why it has been so successful.