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Self-stabilizing Systems
In 1973 Dijkstra introduced to computer science the notion of self-stabilization in the context of distributed systems. He defined a system as self-stabilizing when regardless of its initial state, it is guaranteed to arrive at a legitimate state in a finite number of steps.” A system which is not self-stabilizing may stay in an illegitimate state forever. Dijkstra’s notion of self-stabilization, which originally had a very narrow scope of application, is proving to encompass a formal and unified approach to fault tolerance under a model of transient failures for distributed systems. Dijkstra observed that "The complication is that a node’s behaviour can only be influenced by the part of the total system state description that is available in that node: local actions taken on account of local information must accomplish a global objective.” Later he used the following definition for self-stabilization: We call the system “self-stabilizing” if and only if, regardless of the initial state and regardless of the privilege that is selected each time for the next move, at least one privilege will always be present and the system is guaranteed to find itself in a legitimate state after a finite number of moves. While much of the difficulty of achieving self-stabilization, as well as its benefits, arise out of concurrency, it has applications in sequential systems too. [Source: ACM Computing Surveys, Vol. 25, No. 1, March 1993, Marco Schneider]
 

 

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