Computing Systems' Reliability Dynamics

摘要

The size and complexity of computing systems has increased from one single processor to multiple distributed processors, from individual-separated systems to networked-integrated systems, from small-scale program running to large-scale resource sharing, and from local-area computation to global-area collaboration. A computing system today may contain many processors and communication channels and it may cover a wide area all over the world. They combine both software and hardware that have to function together to complete various tasks. They may incorporate multiple states and their failures may be correlated with one another. These factors make the computing system modeling and analysis complicated. It is necessary to specify more precise models, carefully identifying and quantifying aspects usually approximated or ignored at all. In this paper we face the problem of individuating and evaluating the most common dynamic behaviors and dependencies affecting computing systems. We propose some models to represent such aspects in terms of reliability/availability, basing on dynamic reliability block diagrams (DRBD), a new formalism derived from RBD we developed. In this way we want to provide the guidelines for adequately evaluating computing systems' reliability/availability.