# Time, clocks, and the ordering of events in a distributed system

@article{Lamport1978TimeCA, title={Time, clocks, and the ordering of events in a distributed system}, author={Leslie Lamport}, journal={Commun. ACM}, year={1978}, volume={21}, pages={558-565} }

The concept of one event happening before another in a distributed system is examined, and is shown to define a partial ordering of the events. [... ] Key Method The use of the total ordering is illustrated with a method for solving synchronization problems. The algorithm is then specialized for synchronizing physical clocks, and a bound is derived on how far out of synchrony the clocks can become. Expand

## 9,619 Citations

Logical time in distributed computing systems

- Computer ScienceComputer
- 1991

The partial ordering of events as defined by their causal relationships, that is, the ability of one event to directly, or transitively, affect another is defined. Its generalized and practical…

Scalable synchronization of clocks in distributed environments

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- 2007

A method of pseudo-synchronization of clocks by making use of the occurrence time of events included in direct "happened-before" relations to approximate the actual clock shift between two clocks using the minimum transmission delay of messages between a pair of hosts.

Dynamic Vector Clocks for Consistent Ordering of Events in Dynamic Distributed Applications

- Computer SciencePDPTA
- 2006

An extension to the concept of vector clocks is presented and examined that is meant to overcome the vector clocks’ great drawback: that the number of processes in the distributed system has to be constant and known in advance.

Logical Time in Distributed Software Systems

- Computer ScienceProgramming and Computer Software
- 2004

An argument is provided that justifies the use of logical time as a mechanism for detecting causal relationships between events and the modifications of the vector clock that reduce the average communication overhead while retaining the property of isomorphism.

An Upper and Lower Bound for Clock Synchronization

- Computer Science, MathematicsInf. Control.
- 1984

Time and State in Asynchronous Distributed Systems

- Computer ScienceWiley Encyclopedia of Computer Science and Engineering
- 2008

Different schemes that implement an abstract notion of time and can be used to order events in a distributed system to address two fundamental problems that arise in distributed systems.

Simulating synchronized clocks and common knowledge in distributed systems

- Computer ScienceJACM
- 1993

Time and knowledge are studied in synchronous and asynchronous distributed systems. A large class of problems that can be solved using logical clocks as if they were perfectly synchronized clocks is…

Event Chain Clocks for Performance Debugging in Parallel and Distributed Systems

- Computer ScienceISPA
- 2004

This algorithm can maintain a global physical clock that reflects both the partial order and the elapsed time of all events occurred, and is suitable for parallel program performance debugging.

An Overview of Clock Synchronization

- Computer ScienceFault-Tolerant Distributed Computing
- 1986

A distributed system consists of a set of processors that communicate by message transmission and that do not have access to a central clock, and the technique that is used to coordinate the notion of time is known as clock synchronization.

Tree clocks: An efficient and entirely dynamic logical time system

- Computer ScienceParallel and Distributed Computing and Networks
- 2007

In the paper at hand a new kind of logical clock concept is presented and examined that is meant to overcome the vector clocks' great drawback: that the number of processes in the distributed system has to be constant and known in advance.

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