【摘要】 <正> 一、引言分布式系统需要可靠性保证,例如在线支付系统对安全性提出了很高的要求。因此,分布式系统必须提供可靠性机制,支持关键业务。容错技术是分布式系统运行过程中可靠性保证的重要手段,冗余资源是实现容错的根本保证。单一的容错策略仅适用于特定的应用和特定的系统,无法适应系统状态的动态变化,支持广泛的分布式应用。系统的容错模型应该能够智能地根据外部运行环境的变化,选择合适的容错策略,以便在保证系统可靠性的前提下提高系统资源利用率。自适应容错可以在分布式系统中的各个层次中实现。基于操作系统的自适应容错强烈地依赖于特定的操作系统,系统可移植性差;而在应用程序中实现自适应容错又加重了开更多还原

【Abstract】 Distributed computer systems are widely applied to safety-critical systems,such as air traffic control systems,online paying systems and stock exchange systems. Fault tolerance is a main way of assurance of system reliability. However, distributed systems must always operate in highly dynamic environments, so fault tolerance mechanism should provide more intelligence to adapt itself to in response to the changes in system resource,application demands and user requirements. CORBA is a distributed object computing middleware standard. With support of its core,Object Request Broker (ORB),CORBA provides open and standard communication infrastructure for development and deployment of distributed applications. This paper presents a CORBA-based model for adaptive fault tolerance in distributed systems and describes its structure and implementation schemes on top of a CORBA-compliant object middleware,TongBroker. Finally we give our conclusion.更多还原