Encyclopedia of Algorithms

2008 Edition
| Editors: Ming-Yang Kao

Causal Order, Logical Clocks, State Machine Replication

1978; Lamport
  • Xavier Défago
Reference work entry
DOI: https://doi.org/10.1007/978-0-387-30162-4_65

Keywords and Synonyms

State-machine replication: active replication                

Problem Definition

This entry covers several problems, related with each other. The first problem is concerned with maintaining the causal relationship between events in a distributed system. The motivation is to allow distributed systems to reason about time with no explicit access to a physical clock. Lamport [5] defines a notion of logical clocks that can be used to generate timestamps that are consistent with causal relationships (in a conservative sense). He illustrates logical clocks (also called Lamport clocks) with a distributed mutual exclusion algorithm. The algorithm turns out to be an illustration of state-machine replication. Basically, the algorithm generates a total ordering of the events that is consistent across processes. With all processes starting in the same state, they evolve consistently with no need for further synchronization.

System Model

The system consists of a collection of...

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Recommended Reading

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    Défago, X., Schiper, A., Urbán, P.: Total order broadcast and multicast algorithms: Taxonomy and survey. ACM Comput. Surv. 36, 372–421 (2004)Google Scholar
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    Fidge, C. J.: Logical time in distributed computing systems. IEEE Comput. 24, 28–33 (1991)Google Scholar
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    Lamport, L.: On interprocess communication. Part I: Basic formalism. Distrib. Comput. 1, 77–85 (1986)Google Scholar
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    Lamport, L.: The implementation of reliable distributed multiprocess systems. Comput. Netw. 2, 95–114 (1978)MathSciNetGoogle Scholar
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    Lamport, L.: Time, clocks, and the ordering of events in a distributed system. Commun. ACM 21, 558–565 (1978)zbMATHGoogle Scholar
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    Mattern, F.: Virtual time and global states of distributed systems. In: Cosnard, M., Quinton, P. (eds.) Parallel and Distributed Algorithms, pp.215–226. North-Holland, Amsterdam (1989)Google Scholar
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    Raynal, M., Singhal, M.: Capturing causality in distributed systems. IEEE Comput. 29, 49–56 (1996)Google Scholar
  8. 8.
    Schneider, F.B.: Implementing fault-tolerant services using the state machine approach: a tutorial. ACM Comput. Surv. 22, 299–319 (1990)Google Scholar

Copyright information

© Springer-Verlag 2008

Authors and Affiliations

  • Xavier Défago
    • 1
  1. 1.School of Information ScienceJapan Advanced Institute of Science and Technology (JAIST)IshikawaJapan