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We introduce the notion of stable leader election and derive several algorithms for this problem. Roughly speaking, a leader election algorithm is stable if it ensures that once a leader is elected, it remains the leader for as long as it does not crash and its links have been behaving well, irrespective of the behavior of other processes and links. In(More)
We study the degree of synchrony required to implement the leader election failure detector &#937; and to solve consensus in partially synchronous systems. We show that in a system with <i>n</i> processes and up to <i>f</i> process crashes, one can implement &#937; and solve consensus provided there exists some (unknown) correct process with <i>f</i>(More)
This article determines the weakest failure detectors to implement shared atomic objects in a distributed system with crash-prone processes. We first determine the weakest failure detector for the basic register object. We then use that to determine the weakest failure detector for all popular atomic objects including test-and-set, fetch-and-add, queue,(More)
In the set-agreement problem, n processes seek to agree on at most n−1 different values. This paper determines the weakest failure detector to solve this problem in a message-passing system where processes may fail by crashing. This failure detector, called the Loneliness detector and denoted L, outputs one of two values, " true " or " false " such that:(More)
This paper defines the fault-tolerant mutual exclusion problem in a message-passing asynchronous system and determines the weakest failure detector to solve the problem. This failure detector, which we call the trusting failure detector, and which we denote by T , is strictly weaker than the perfect failure detector P but strictly stronger than the(More)
We study the feasibility and cost of implementing &#937;---a fundamental failure detector at the core of many algorithms---in systems with weak reliability and synchrony assumptions. Intuitively, &#937; allows processes to eventually elect a common leader. We first give an algorithm that implements &#937; in a weak system <i>S</i> where processes are(More)
We determine the weakest failure detectors to solve several fundamental problems in distributed message-passing systems, for <i>all</i> environments -- i.e., regardless of the number and timing of crashes. The problems that we consider are: implementing an atomic register, solving consensus, solving quittable consensus (a variant of consensus in which(More)
At vobis male sit, malae tenebrae Orci, quae omnia bella devoratis: tam bellum mihi passerem abstulistis. [6] Abstract In the population protocol model introduced by Angluin et al. [2], a collection of agents, which are modelled by finite state machines, move around unpredictably and have pairwise interactions. The ability of such systems to compute(More)
We consider the problem of generic broadcast in asynchronous systems with crashes, a problem that was rst studied in 12]. Roughly speaking, given a \connict" relation on the set of messages, generic broadcast ensures that any t wo messages that connict are delivered in the same orderr messages that do not connict may be delivered in diierent order. In this(More)
At the heart of distributed computing lies the fundamental result that the level of agreement that can be obtained in an asynchronous shared memory model where t processes can crash is exactly t + 1. In other words, an adversary that can crash any subset of size at most t can prevent the processes from agreeing on t values. But what about all the other(More)