Time, Clocks, and the Ordering of Events in a Distributed System, Leslie Lamport, Communications of the ACM, Volume 21, Number 7, pages 558-556, July 1978.  Home/Search   Document Not in Database   Summary   ACM   TOC   Related Articles   Check

....trying to ensure clock synchronization across portable computers is problematic. However, keeping servers clocks reasonably close is desirable so that the induced Write order is consistent with a user s perception of the order in which Writes are submitted. Bayou servers maintain logical clocks [20] to timestamp new Writes. A server s logical clock is generally synchronized with ts real time system clock, but, to preserve the causal ordering of Write operations, the server may need to advance its logical clock when Writes are received during ann entropy. Enforcing a global order on ....

L. Lampoft. Time, clocks, and the ordering of events in a distributed system. Communications of the A CM 21 (7):558-565, July 1978.

....tests remain unavailable. The others are reconfigured into new fail stop processors. 4. Other Approaches to Fault tolerance Our implementation of a k fail stop processor is an application of the state machine approach, a general approach for constructing distributed programs first described in [L178a] and later extended for environments in which failures could occur in [L178b, LI81, S82] Given any program, a distributed version that can tolerate up to k failures can be constructed by running that program on 2k 1 processors connected by a corn munications network in which message origins ....

Lampoft, L. Time, Clocks, and the Ordering of Events in a Distributed System. CACM 1, 7 (July 1978), 558-565.

....paper. SOur protocols can be extended to the case where clocks are only approximately synchronized [14] 6Another approach would be assume that servers are interconnected with redundant broadcast busses [2, 8] We have not pursued this approach. Define to be the potential causality relation [12] on server events el and e2. Thus is the transitive closure of the following relation : el e2 iff both el and e occur at the same server s and el occurs before e, or el is a send event and e is the corresponding receive event. Informally, we say a request m is an update request if it changes ....

Leslie Lampoft. Time, Clocks, and the Ordering of Events in a Distributed System. Communications of the ACM, 21(7):558-565, July 1978.

....[1] use asynchronous message sending and are particulary adapted for mobile platforms thanks to features of message queuing (which ensures a certain reliability) or message ordering (which provides a way to reduce the non determinism) for instance. A common ordering mechanism uses logical time [2] to order events according to the causal order [3] The causal precedence relation induces a partial order on the events of a distributed com putation. It is a powerful concept, which helps to solve a variety of problems in distributed systems like algorithms design, concurrency measurement, ....

L. Lampoft. Time, Clocks, and the Ordering of Events in a Distributed System, 1978.

....are conveyed to the service in the argument label. One way to manage labels is to have the system append them to all messages automatically and merge them whenever messages are received. Using this approach will lead to the well known causal or happened before order defined by Lampon [18]. However, better performance can be achieved if clients control the use of labels explicitly. This explicit approach can lead to smaller messages, since often it will not be necessary to include labels in them; this point is discussed further in Section 5.2. Also, the client has considerable ....

Lainport, L. Time, Clocks, and the Ordering of Events in a Distributed System. Comm. of the ACM 21(7):558-565, July, 1978.

....and the visualization and user interface facilities and the debugging procedure. ALCOM IT Requirements for the simulation of distr. protocols COMPUTER TECHNOLOGY INSTITUTE 7 Synchronization Algorithms 1. The Clock Synchronization Algorithm of L. Lamport Description of the problem Lamport [Lamp78] presented a distributed algorithm for synchronizing a system of logical clocks which can be used to totally order the events. The use of the total ordering is illustrated with a method for solving synchronization problems. The algorithm is also specialized for synchronizing physical clocks. ....

"Time, Clocks, and the ordering of events in a distributed system", Leslie Lamport, Communications of the ACM, July 1978, Vol. 21, No 7, pp. 558-565.

....step times must also be considered. We provide two simulations that show how to transform an algorithm designed in the simple programming model to run in a more realistic distributed system. One of our simulations is an extension of previous results on the use of inaccurate clocks by Lampoft [5], Neiger and Toueg [13] and Welch [17] Our extensions suggest several powerful design techniques for algorithms that are to be run in distributed systems with clocks whose divergence from real time is bounded. We demonstrate these techniques by providing a new algorithm for distributed ....

....define s.A, to be the state of A, such that ( A, tc = cic ana ( A, o = clock. s start(C(A, e) iffs.A, start(A, and s. now = O. 6The requirement that the clock time at which a message is deliv ered is never less than the clock time at which it was sent was first dentified by Lampoft in [5]. The use of buffering to achieve this property was suggested by Welch in [17] and Neiger and Toueg in [la] 125 SESDMSO, j, Effect: b. bii o ( now) RECVMS (i, Precondition: m, t) b 0 t dl now d 2 Effect: o,s : o ( 0 Precondition: m, b, s s.t. t d now Effect: now : now ....

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L. Lampoft, Time, Clocks, and the Ordering of Events in a Distributed System, Communications of the ACM, Vol. 21, Number 7, July 1978.

No context found.

Time, Clocks, and the Ordering of Events in a Distributed System, Leslie Lamport, Communications of the ACM, Volume 21, Number 7, pages 558-556, July 1978.

No context found.

Leslie Lampoft. Time, clocks, and the ordering of events in a distributed system. Communications of the ACM, 21(7):558-565, July 1978.

No context found.

L. Lamppost. Time, clocks, and the ordering of events in a distributed systems. Comm. ACM, 21(7), July, 1978, 558-565.

No context found.

Time, clocks, and the ordering of events in a distributed system. Communications of the ACM, 21(7):558--565. Leasure, B. 1990 (August).

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