UML and the Tasks Specific to Real-Time Development

The use of UML for developing real-time systems is rapidly gaining attention from the industry. The future release of a response to the OMG RFP for a “UML profile for performance, scheduling and time” [1] will probably boost the acceptance of UML by the real-time development community. The team formed inside OMG’s Real-Time Analysis and Design working group, preparing the response to the above mentioned RFP, is working on identifying the concepts, mechanisms and techniques currently used in real-time systems modeling and analysis. The goal is to introduce in UML all the support needed for capturing (a maximum of) real-time-specific requirements and information in UML models, performing the common real-time development tasks directly on UML models. However, the early stages of the real-time development process involve some very specific tasks, beside the usual analysis and design stages. Examples include: scheduling analysis, formal verification of critical timing properties of the system, and performance evaluation. All these steps should be considered in the definition of the UML profile for real-time, since the supporting concepts needed for performing these tasks on UML models are very different. This contribution argues for a systematic review of all the development steps of real-time systems, in order to include the appropriate supporting concepts in a UML profile for real-time. Similar efforts have been made for other modeling languages, such as SDL [6], which are currently supporting a broader set of development tasks than UML, including scheduling analysis, formal verification of timing properties and performance evaluation. This contribution considers the tasks of formal verification and performance evaluation, and shows how the needed concepts could beneficently be introduced in UML.