J. Xu, F. Di Giandomenico, A. Bondavalli and S. Chiaradonna
University of Newcastle upon Tyne. 1997.
Most existing studies assume that a fixed amount of hardware and system resources is bound statically to a given architecture. However, in a general purpose distributed system multiple unrelated applications may compete for system resources such as processors, memories and communication devices, thereby exhibiting highly dynamic system characteristics. Our architectural solutions are directed at such systems and thus have an important concern with adaptation - adaptive execution of redundant programs so as to minimize hardware resource consumption and to shorten the response time, as much as possible, for a required level of fault tolerance. In comparison with static architectures, the analytical results under some realistic scenarios show that adaptive (i.e. dynamic) designs generally make more efficient use of available resources without compromising dependability. Dynamic architectures often have a longer worst-case response time, but in some application scenarios they may have a higher probability of making a timely response than static designs.