The notation used for the COMET/RTE method is the Unified Modeling Language (UML), supplemented with the Systems Modeling Language (SysML) and Modeling and Analysis of Real-Time Embedded Systems (MARTE). This chapter provides a brief overview of these three related visual modeling notations.

The Object Management Group (OMG) maintains UML and SysML as standards. The UML notation has evolved since it was first adopted as a standard in 1997. A major revision to the standard was the introduction of UML 2.0 in 2003. Since then there have been further minor changes, and the latest version of the standard is UML 2.4. The versions of the standard before UML 2 are referred to as UML 1.x, and the current version is generally referred to as UML 2. SysML is based on UML 2, using some parts of UML 2 and extending it in other areas for systems modeling. MARTE is a more recent UML profile for real-time embedded systems. Each of these notations is of a significant size, and it is therefore beneficial for the real-time system modeler to pick and choose carefully among the multitude of diagrams and stereotypes provided by these notations.

The UML notation has grown substantially over the years and supports many diagrams. SysML and MARTE extend the modeling notations further. The approach taken in this book is to use only those parts of the UML and SysML notation that provide a distinct benefit to the design of real-time embedded systems, and to use the parts of MARTE that can be most usefully blended with UML and SysML for the design of these systems. This chapter describes the main features of the UML, SysML, and MARTE notations that are particularly suited for real-time design using the COMET/RTE method. The purpose of this chapter is not to be a full exposition of UML, SysML, and MARTE, because several detailed books exist on these topics, but rather to provide a brief overview of each. The main features of each of the diagrams used in this book are briefly described, but lesser-used features are omitted.

MODEL-DRIVEN ARCHITECTURE WITH SYSML AND UML

In the OMG's view, “modeling is the designing of software applications before coding” (OMG 2015). The OMG promotes model-driven architecture as the approach in which UML models of the software architecture are developed prior to implementation.