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Book A New Fault tolerant Algorithm for Clock Synchronization

Download or read book A New Fault tolerant Algorithm for Clock Synchronization written by Jennifer Lundelius and published by . This book was released on 1984 with total page 29 pages. Available in PDF, EPUB and Kindle. Book excerpt: We describe a new fault-tolerant algorithm for solving a variant of Lamport's clock synchronization problem. The algorithm is designed for a system of distributed processes that communicate by sending messages. Each process has its own read-only physical clock whose drift rate from real time is very small. By adding a value to its physical clock time, the process obtains its local time. The algorithm solves the problem of maintaining closely synchronized local times, assuming that processes' local times are closely synchronized initially. The algorithm is able to tolerate the failure of just under a third of the participating processes. It maintains synchronization to within a small constant, whose magnitude depends upon the rate of clock drift, the message delivery time, and the initial closeness of synchronization. We also give a characterization of how far the clocks drift from real time. Reintegration of a repaired process can be accomplished using a slight modification of the basic algorithm. A similar style algorithm can also be used to achieve synchronization initially. (Author).

Book An Extension to Schneider s General Paradigm for Fault tolerant Clock Synchronization

Download or read book An Extension to Schneider s General Paradigm for Fault tolerant Clock Synchronization written by Paul S. Miner and published by . This book was released on 1992 with total page 60 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book An Efficient Fault tolerant Algorithm for Clock Synchronization

Download or read book An Efficient Fault tolerant Algorithm for Clock Synchronization written by International Business Machines Corporation. Research Division and published by . This book was released on 1983 with total page 21 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book A Verified Design of a Fault Tolerant Clock Synchronization Circuit

Download or read book A Verified Design of a Fault Tolerant Clock Synchronization Circuit written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-07-17 with total page 104 pages. Available in PDF, EPUB and Kindle. Book excerpt: Schneider demonstrates that many fault tolerant clock synchronization algorithms can be represented as refinements of a single proven correct paradigm. Shankar provides mechanical proof that Schneider's schema achieves Byzantine fault tolerant clock synchronization provided that 11 constraints are satisfied. Some of the constraints are assumptions about physical properties of the system and cannot be established formally. Proofs are given that the fault tolerant midpoint convergence function satisfies three of the constraints. A hardware design is presented, implementing the fault tolerant midpoint function, which is shown to satisfy the remaining constraints. The synchronization circuit will recover completely from transient faults provided the maximum fault assumption is not violated. The initialization protocol for the circuit also provides a recovery mechanism from total system failure caused by correlated transient faults. Miner, Paul S. Langley Research Center ALGORITHMS; CIRCUITS; CLOCKS; FAULT TOLERANCE; SYNCHRONISM; CONVERGENCE; PROTOCOL (COMPUTERS); PROVING; SYSTEM FAILURES...

Book An Extension to Schneider s General Paradigm for Fault Tolerant Clock Synchronization

Download or read book An Extension to Schneider s General Paradigm for Fault Tolerant Clock Synchronization written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-07-02 with total page 58 pages. Available in PDF, EPUB and Kindle. Book excerpt: In 1987, Schneider presented a general paradigm that provides a single proof of a number of fault tolerant clock synchronization algorithms. His proof was subsequently subjected to the rigor of mechanical verification by Shankar. However, both Schneider and Shankar assumed a condition Shankar refers to as a bounded delay. This condition states that the elapsed time between synchronization events (i.e., the time that the local process applies an adjustment to its logical clock) is bounded. This property is really a result of the algorithm and should not be assumed in a proof of correctness. This paper remedies this by providing a proof of this property in the context of the general paradigm proposed by Schneider. The argument given is a generalization of Welch and Lynch's proof of a related property for their algorithm. Miner, Paul S. Langley Research Center...

Book Experimental Validation of Clock Synchronization Algorithms

Download or read book Experimental Validation of Clock Synchronization Algorithms written by Daniel L. Palumbo and published by . This book was released on 1992 with total page 30 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book A Survey of Provably Correct Fault tolerant Clock Synchronization Techniques

Download or read book A Survey of Provably Correct Fault tolerant Clock Synchronization Techniques written by and published by . This book was released on 1988 with total page 32 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Fault tolerant External Clock Synchronization

Download or read book Fault tolerant External Clock Synchronization written by Flaviu Cristian and published by . This book was released on 1994 with total page 38 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Validation of a Fault tolerant Clock Synchronization System

Download or read book Validation of a Fault tolerant Clock Synchronization System written by Ricky W. Butler and published by . This book was released on 1984 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Formal Verification of a Fault Tolerant Clock Synchronization Algorithm

Download or read book Formal Verification of a Fault Tolerant Clock Synchronization Algorithm written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-07-24 with total page 226 pages. Available in PDF, EPUB and Kindle. Book excerpt: A formal specification and mechanically assisted verification of the interactive convergence clock synchronization algorithm of Lamport and Melliar-Smith is described. Several technical flaws in the analysis given by Lamport and Melliar-Smith were discovered, even though their presentation is unusally precise and detailed. It seems that these flaws were not detected by informal peer scrutiny. The flaws are discussed and a revised presentation of the analysis is given that not only corrects the flaws but is also more precise and easier to follow. Some of the corrections to the flaws require slight modifications to the original assumptions underlying the algorithm and to the constraints on its parameters, and thus change the external specifications of the algorithm. The formal analysis of the interactive convergence clock synchronization algorithm was performed using the Enhanced Hierarchical Development Methodology (EHDM) formal specification and verification environment. This application of EHDM provides a demonstration of some of the capabilities of the system. Rushby, John and Vonhenke, Frieder Unspecified Center NASA-CR-4239, NAS 1.26:4239 NAS1-17067; RTOP 505-66-21-01...

Book A Byzantine Fault Tolerant Self Stabilizing Protocol for Distributed Clock Synchronization Systems

Download or read book A Byzantine Fault Tolerant Self Stabilizing Protocol for Distributed Clock Synchronization Systems written by National Aeronaut Administration (Nasa) and published by . This book was released on 2020-08-05 with total page 38 pages. Available in PDF, EPUB and Kindle. Book excerpt: Embedded distributed systems have become an integral part of safety-critical computing applications, necessitating system designs that incorporate fault tolerant clock synchronization in order to achieve ultra-reliable assurance levels. Many efficient clock synchronization protocols do not, however, address Byzantine failures, and most protocols that do tolerate Byzantine failures do not self-stabilize. Of the Byzantine self-stabilizing clock synchronization algorithms that exist in the literature, they are based on either unjustifiably strong assumptions about initial synchrony of the nodes or on the existence of a common pulse at the nodes. The Byzantine self-stabilizing clock synchronization protocol presented here does not rely on any assumptions about the initial state of the clocks. Furthermore, there is neither a central clock nor an externally generated pulse system. The proposed protocol converges deterministically, is scalable, and self-stabilizes in a short amount of time. The convergence time is linear with respect to the self-stabilization period. Proofs of the correctness of the protocol as well as the results of formal verification efforts are reported. Malekpour, Mahyar R. Langley Research Center NASA/TM-2006-214322, L-19262 WBS 457280.02.07.07 CLOCKS; SYNCHRONISM; PROVING; FAULT TOLERANCE; CONVERGENCE; EMBEDDING; ALGORITHMS; SAFETY; PROTOCOL (COMPUTERS); PROGRAM VERIFICATION (COMPUTERS); FAILURE

Book Dynamic Fault tolerant Clock Synchronization

Download or read book Dynamic Fault tolerant Clock Synchronization written by International Business Machines Corporation. Research Division and published by . This book was released on 1989 with total page 50 pages. Available in PDF, EPUB and Kindle. Book excerpt: