Time weaver

摘要

Embedded real-time systems are deployed in a wide range of application domains including transportation systems, automated manufacturing, process control, defense, aerospace, and telecommunications. These systems must satisfy not only logical functional requirements but also para-functional properties such as timeliness, Quality of Service (QoS) and reliability. The cross-cutting behaviors imposed by these para-functional properties and dependencies on operational characteristics (e.g. hardware, OS and middleware platforms used) have traditionally led to hard-to-code, hard-to-understand and hard-to-change software. The net result is that productivity improvements in embedded software development have been miniscule compared to improvements in computing and network technologies. We propose a software-through-models framework for the concurrent construction of behavioral models and executable code. Our framework, which can lead to high degrees of cost-effective reuse of embedded software components, decomposes inter-component relationships with an abstraction named coupler. This decomposition enables the separation of para-functional aspects into multiple semantic dimensions (e.g. timing, event flow, concurrency, fault-tolerance, deployment) that can be modified independent of one another. The impact of changes in one dimension on the realization of other dimensions is automatically projected and managed. Platform dependencies are also captured separately, enabling a code-generation subsystem to re-use the same components across a wide range of heterogeneous platforms and applications. System components can be recursively composed or decomposed. An analyzable software structure is enforced such that the end-to-end timing behavior of the resulting system can be verified. A visual tool called Time Weaver supports the framework and has been used to model avionics systems, automotive systems and signal processing systems. The software can be downloaded from[4].