Modeling and simulation of timing behavior with the Timing Definition Language ( TDL )

Most of the existing modeling methods and tools for embedded application development use levels of abstraction where execution and communication times of computational tasks are not adequately captured. Thus, properties such as time and value determinism, which are crucial for safety-critical real-time systems, cannot be guaranteed when refining the model to move it closer to a target platform. In many cases, the link between the abstract model and its implementation is broken during the refinement process. An additional problem is that the resulting software components are often not portable and composable. The Logical Execution Time (LET) abstraction has been proposed to deal with these issues and to offer a correct-by-construction development that formally guarantees time and value determinism and that delivers portable embedded software components. LET allows the explicit, platform-independent specification of execution times. This chapter deals with the modeling and simulation of safety-critical embedded applications where timing requirements are specified in the Timing Definition Language (TDL) which supports the LET abstraction. TDL provides a programming model for both the time-triggered paradigm and the event-triggered paradigm. TDL components can be automatically deployed to large-scale distributed systems. We present a selection of TDL constructs and sketch the