Fault detection, isolation, and reconfiguration in the fault tolerant multiprocessor

Abstract

The Fault Tolerant Multiprocessor is a highly reliable computer designed to meet a goal of 10 ~ failures per hour. To a large extent, this level of reliability depends upon the ability to detect and isolate faults rapidly and accurately, purge the faulty module, and dynamically reconfigure the remaining good modules. This paper describes fault detection, isolation, and recovery methodology employed in the Fault Tolerant Multiprocessor. The second part of the paper deals with experimental results obtained by actually injecting faults at the pin level in the Fault Tolerant Multiprocessor. Over 21,000 faults were injected in the central processing unit, memory, bus interface circuits, and error detection, masking, and error reporting circuits of one line replaceable unit of the multiprocessor. Detection, isolation, and reconfiguration times for each fault were recorded. These results were found to be in close agreement with earlier assumptions made in reliability modeling. The experimental results are summarized in this paper.