Constructing distributed real-time systems with DROL real-time objects

In this paper, the semantics of inter-object communication protocols supported by the distributed real-time programming language DROL that is an extension of C++ based on the Distributed Real-time Object (DRO) model is described. A characteristic common to these protocols is the introduction of a new notion, least suffering. The least suffering assures users of notification of network faults within a required timing constraint and rapid recovery from them. Thus, this notion allows users to construct real-time applications on widely distributed environments. It is impossible for previously proposed real-time programming languages to do it. Through the description of application programs and the discussion of their behavior, we show the effectiveness of the least suffering.