GUARDS: A Generic Upgradable Architecture for Real-Time Dependable Systems

Abstract. The development and validation of fault-tolerant computers for critical real-time applications are currently both costly and time-consuming. Often, the underlying technology is out-of-date by the time the computers are ready for deployment. Obsolescence can become a chronic problem when the systems in which they are embedded have lifetimes of several decades. This paper gives an overview of the work carried out in a project that is tackling the issues of cost and rapid obsolescence by defining a generic fault-tolerant computer architecture based essentially on commercial off-the-shelf (COTS) components (both processor hardware boards and real-time operating systems). The architecture uses a limited number of specific, but generic, hardware and software components to implement an architecture that can be configured along three dimensions: redundant channels, redundant lanes and integrity levels. The two dimensions of physical redundancy allow the definition of a wide variety of instances with different fault-tolerance strategies. The integrity level dimension allows application components of different levels of criticality to co-exist in the same instance. The paper describes the main concepts of the architecture, the supporting environments for development and validation, and the prototypes currently being implemented.