时控令版协议在分布式系统临界区访问中的应用

分布式系统临界区互斥访问方法大体上有集中式算法、分布式算法和令版环算法三种。本文在简单讨论了这三种方法后，结合在分布式光纤数据接口FDDI中应用的时控令牌协议，对令版环算法进行了改造，使得令版特环一周的时间可以控制在有限范围内，从而为丢失令牌的判断提供了理论依据。模拟实验对改进引起的综合影响进行评价，认为该该改进是可取的。

Application of the Timed-Token Protocol in Visiting the Critical Region of Distributed Systems

On the basis of the known mutual ex clusion methods including centralized,distributed and token ring algorithms for a process to access the critical region in distributed systems,this paper improv es the token ring algorithm using the main idea of the timed-token protocol,whi ch is applied in FDDIs,to provide the theoretic basis for distinguishing the los s of tokens by confining the rotation time of one cycle to a limited range.The e mulation results show that this improvement is acceptable.