Distributed Computing

, Volume 20, Issue 5, pp 343–358 | Cite as

Failure detectors as type boosters

  • Rachid Guerraoui
  • Petr Kouznetsov
Open Access


The power of an object type T can be measured as the maximum number n of processes that can solve consensus using only objects of T and registers. This number, denoted cons(T), is called the consensus power of T. This paper addresses the question of the weakest failure detector to solve consensus among a number k > n of processes that communicate using shared objects of a type T with consensus power n. In other words, we seek for a failure detector that is sufficient and necessary to “boost” the consensus power of a type T from n to k. It was shown in Neiger (Proceedings of the 14th annual ACM symposium on principles of distributed computing (PODC), pp. 100–109, 1995) that a certain failure detector, denoted Ω n , is sufficient to boost the power of a type T from n to k, and it was conjectured that Ω n was also necessary. In this paper, we prove this conjecture for one-shot deterministic types. We first show that, for any one-shot deterministic type T with cons(T) ≤ n, Ω n is necessary to boost the power of T from n to n + 1. Then we go a step further and show that Ω n is also the weakest to boost the power of (n + 1)-ported one-shot deterministic types from n to any k > n. Our result generalizes, in a precise sense, the result of the weakest failure detector to solve consensus in asynchronous message-passing systems (Chandra et al. in J ACM 43(4):685–722, 1996). As a corollary, we show that Ω t is the weakest failure detector to boost the resilience level of a distributed shared memory system, i.e., to solve consensus among n > t processes using (t − 1)-resilient objects of consensus power t.


Correct Process Reduction Algorithm Failure Detector Failure Pattern Shared Object 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


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Copyright information

© Springer-Verlag 2007

Authors and Affiliations

  1. 1.Distributed Programming Laboratory, EPFLLausanneSwitzerland
  2. 2.Max Planck Institute for Software SystemsSarbrückenGermany

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