A Timed Multitasking Architecture for Distributed Embedded Systems

Abstract

Abstract — The paper presents a software architecture for Distributed Timed Multitasking- a new model of computation that can be used to engineer open, and the same time, predictable embedded systems. Systems are composed from components (actors) that communicate transparently by exchanging labeled messages (signals) over a real-time network. Actors may be viewed as real-time tasks with event-triggered input/output signal drivers. The latter are executed atomically at precisely specified time instants, resulting in the elimination of transaction I/O jitter. Drivers are actually integrated into a middleware component- the Timed Communication Bus, which provides for complete separation of computation and communication, as well as transparent interaction between embedded actors, independent of their allocation on network nodes. The Communication Bus has been conceived as a subsystem of a distributed timed multitasking kernel whose architecture and operation are discussed as well. Index Terms — Distributed hard real-time systems, componentbased design, embedded actors, signal-based communication, timed multitasking, semi-static cyclic scheduling I