Towards a declarative modeling and execution framework for real-time systems

Abstract

Our work is a contribution towards addressing what Thomas Henziger called the grand challenge in embedded software design [5]: "offering high-level programming models that exposes the execution properties of a system in a way that permits the programmer to express desired reaction and execution requirements, permits the compiler and run-time systems to ensure that these requirements are satisfied". In the programming model we describe here, the developer states the permissible timing behavior of the system, a system synthesis step involving both analysis and optimization generates a scheduling solution which at run-time is enforced by the execution environment. With respect to the synchronous programming models, our approach implements a weaker version of time-determinism, still providing a form of timing-predictability sufficient in many applications while remaining closer to mainstay software development practices. This approach is currently being implemented and experimented in the CPAL language development tools and associated runtime environment.

CPAL: high-level abstractions for safe embedded systems

“…The reader is referred to [12] and [2] for a more thorough comparison with other programming languages and, more generally, programming paradigms, especially those belonging to the realm of synchronous approaches.…”

“…"State the what, not the how": the idea is that the developer should state the permissible behavior of the program, and a system synthesis step involving both analysis and optimization generates executable artifacts that guarantee the requirements to be met. The feasibility of this idea with respect to scheduling has been assessed in [2,18] but other dimensions such as power consumption and dependability remains to be studied. A question of particular interest in the targeted application domain of CPAL is how an application can be made sufficiently robust to respect a given safety level (e.g., SIL2) by introducing at the synthesis step fault-tolerant mechanisms such as for instance redundant executions or watchdog mechanisms.…”