System-level diagnosis is an important technique for fault detection and location in multiprocessor computing systems. Efficient diagnosis is highly desirable for sustaining the original system power. Moreover, effective diagnosis is particularly important for a multiprocessor system with high scalability but low connectivity. Most of the existing results are not applicable in practice because of the high diagnosis cost and limited diagnosability. Over-d fault diagnosis, where d is the diagnosability, has only been addressed using a probabilistic method in the literature. Aiming at these two issues, we propose a hierarchical adaptive system-level diagnosis approach for hypercube systems using a divide-and-conquer strategy. We first propose a conceptual algorithm HADA to formulate a rigorous analysis. Then we present its practical variant IHADA. In HADA and IHADA, the over-d fault problem is inherently tackled through a deterministic method. Three measures for diagnosis cost (diagnosis time, number of tests, and number of test links) are analyzed for the proposed algorithms. It is proved that the diagnosis cost required by our approach is lower than in previous diagnosis algorithms. It is shown that the diagnosis cost for the proposed algorithms depends on the number and location of faulty units in the system and the cost is extremely low when only a small number of faulty units exist. It is also shown that our algorithms are characterized by lower costs than a pessimistic diagnosis algorithm which trades lower diagnosis cost for a lower degree of accuracy. Experimental results on the nCUBE are provided.

Traditional adaptive centralized system diagnosis assumes a fully connected network topology, hence it can not be used in a number of classes of multiprocessor systems, such as meshes. This paper proposes an adaptive system-level diagnosis algorithm for meshes with wraparound, such as Intel Paragon machine. It is proved that the diagnosis cost required by the proposed approach is lower than the known diagnosis algorithms which can be applied to mesh architectures. Also over-d fault problem can be efficiently solved by our method, where d is the diagnosability.

An algorithm for fault diagnosis (detection and location) of baseline interconnection networks in the presence of multiple faults is presented. This algorithm requires 2(1+log/sub 2/ N) tests, where log/sub 2/ N is the number of stages. Multiple fault diagnosis is possible provided: (a) there exists no logically erroneous and unidentified outputs in each faulty switching element and (b) multiple link faults (of the type stuck-at-0 stuck-at-1) do not exist in the network. Fault location is accomplished using an iterative process which checks each stage of the multistage interconnection network. A new functional description of the network is introduced to facilitate fault location.>