Emergence of an Architectural Topology for

Safety-Critical Real-Time Systems

Mark Nicholson and Alan Burns

Department of Computer Science,
University of York,
Heslington,
York,
YO1 5DD.
Tel: (01904) 432789

Abstract

Constructing a system architecture for a distributed safety-critical real-time control system is a complex task. This complexity results from non-functional as well as functional requirements. One issue of interest to the designer of a system architecture is that of selecting a topology such that dependability and timing characteristics of a system emerge during the design process. A topology is a set of configured hardware and software primitive resources (units). A unit may be a processor, sensor, piece of software, etc. Selecting a topology has hitherto been approached in a very simplistic manner leading to a system topology being set early in the design process.

In this report we investigate one aspect of the topology selection issue in depth; the architectural topology problem in which a number of alternative physical resources are employed to support a logical implementation (an architectural component) of a control

action (Service). We show how a quantitative evaluation of alternative architectural topologies can be used to guide the process of building an architectural topology.

Keywords: Dependability, System Architecture, Design Support, Tools, Genetic Algorithms