An optimal number of microprocessor units with watchdog processor
A large number of microprocessors (mu Ps) have been widely used in many practical fields. A watchdog processor (WDP) is the most convenient coprocessor to monitor the behavior of a mu P since it is simple and low-priced. This paper considers a system with N mu P units, where each mu P unit consists of mu P and WDP. When errors of a mu P have occurred, a WDP detects them and resets a mu P to an initial state. The reset number is checked at constant time T. If more than K resets have been made at time T, a mu P becomes permanently faulty and one of other mu P units in standby begins to operate. The mean time and the expected cost until system failure are derived. An optimal number N* which minimizes the expected cost is discussed. (C) 2000 Elsevier Science Ltd. All rights reserved.
microprocessors watchdog processor reliability redundancy