The Role of a Maintenance Processor for a General-Purpose Computer System

Research and development in fault-tolerant computing has shown that a dedicated processor, called a maintenance processor, can efficiently monitor, control, and maintain the operation of its host computer. This paper presents the general system structure and common functional capabilities of the maintenance processor, and illustrates its utilization with a survey of actual implementations available in the general-purpose computer industry. An analytical model is then presented to evaluate the impact of the maintenance processor on the host system reliability, availability, and serviceability (RAS). Examples given show negligible additional downtime and system failures due to the unavailability of a typical maintenance processor. This observation, plus others included in the paper, strongly indicate that a maintenance processor can be designed and used as the focal point of most system support activities. The approach simplifies the hardware and software structure of the host computer, and improves the total system RAS.