The design and performance of component middleware for QoS-enabled deployment and configuration of DRE systems

Quality of service (QoS)-enabled component middleware can help reduce the complexity of deploying and con guring QoS aspects, such as priorities and rates of invocation. Few empirical studies have been conducted, however, to guide developers of distributed real-time and embedded (DRE) systems in choosing among alternative designs and performance optimizations. Moreover, few empirical studies have been conducted to examine the performance and exibility trade-o s between standardsbased and domain-speci c DRE middleware solutions. This paper makes three key contributions to research on QoS-enabled component middleware for DRE systems. First, it describes optimizations applied to an implementation of the OMG's Deployment and Con guration (D&C) of Components speci cation that enable performance trade-o s between QoS aspects of DRE systems. Second, it compares the performance of several dynamic and static con guration mechanisms to help guide the selection of suitable con guration mechanisms based on speci c DRE system requirements. Third, it compares the performance of our static standards-based approach to an avionics domain-speci c approach. Our results show that these optimizations (1) provide developers improved control over key trade-o s between exibility and performance at di erent stages of the DRE system lifecycle, (2) enhance trustworthiness of component-based DRE systems by supporting greater customization of how they are con gured to meet speci c requirements of each application, and (3) o er greater exibility at a reasonable performance cost, compared to a domain-speci c approach.