Download or read book Verification of Fault tolerant Clock Synchronization Systems written by Paul S. Miner and published by . This book was released on 1993 with total page 148 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Validation of a Fault Tolerant Clock Synchronization System written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-08-06 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt: A validation method for the synchronization subsystem of a fault tolerant computer system is investigated. The method combines formal design verification with experimental testing. The design proof reduces the correctness of the clock synchronization system to the correctness of a set of axioms which are experimentally validated. Since the reliability requirements are often extreme, requiring the estimation of extremely large quantiles, an asymptotic approach to estimation in the tail of a distribution is employed. Butler, R. W. and Johnson, S. C. Langley Research Center NASA-TP-2346, L-15799, NAS 1.60:2346 RTOP 505-34-13
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:
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...
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...
Download or read book Formal Verification of a Fault Tolerant Clock Synchronization Algorithm written by John Rushby and published by . This book was released on 1989 with total page 232 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book A Verified Design of a Fault tolerant Clock Synchronization Circuit Preliminary Investigations written by and published by . This book was released on 1992 with total page 106 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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
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...
Download or read book Model Checking a Byzantine Fault Tolerant Self Stabilizing Protocol for Distributed Clock Synchronization Systems written by Mahyar R. Malekpour and published by BiblioGov. This book was released on 2013-08 with total page 40 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report presents the mechanical verification of a simplified model of a rapid Byzantine-fault-tolerant self-stabilizing protocol for distributed clock synchronization systems. This protocol does not rely on any assumptions about the initial state of the system. This protocol tolerates bursts of transient failures, and deterministically converges within a time bound that is a linear function of the self-stabilization period. A simplified model of the protocol is verified using the Symbolic Model Verifier (SMV) [SMV]. The system under study consists of 4 nodes, where at most one of the nodes is assumed to be Byzantine faulty. The model checking effort is focused on verifying correctness of the simplified model of the protocol in the presence of a permanent Byzantine fault as well as confirmation of claims of determinism and linear convergence with respect to the self-stabilization period. Although model checking results of the simplified model of the protocol confirm the theoretical predictions, these results do not necessarily confirm that the protocol solves the general case of this problem. Modeling challenges of the protocol and the system are addressed. A number of abstractions are utilized in order to reduce the state space. Also, additional innovative state space reduction techniques are introduced that can be used in future verification efforts applied to this and other protocols.
Download or read book Mechanical Verification of a Schematic Protocol for Byzantine Fault tolerant Clock Synchronization written by Natarajan Shankar and published by . This book was released on 1991 with total page 93 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: "Schneider [8] generalizes a number of protocols for Byzantine fault tolerant clock synchronization and presents a uniform proof for their correctness. We present a machine checked proof of this schematic protocol that revises some of the details in Schneider's original analysis. The verification was carried out with the EHDM system [7] developed at the SRI Computer Science Laboratory. The mechanically checked proofs include the verification that the egocentric mean function used in Lamport and Melliar-Smith's Interactive Convergence Algorithm [4] satisfies the requirements of Schneider's protocol."
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:
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:
Download or read book A Byzantine Fault Tolerant Self Stabilizing Protocol for Distributed Clock Synchronization Systems written by Nasa Technical Reports Server (Ntrs) and published by BiblioGov. This book was released on 2013-07 with total page 40 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.
Download or read book Formal Techniques in Real Time and Fault Tolerant Systems written by Werner Damm and published by Springer. This book was released on 2003-06-30 with total page 437 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume contains the proceedings of FTRTFT 2002, the International S- posium on Formal Techniques in Real-Time and Fault-Tolerant Systems, held at the University of Oldenburg, Germany, 9–12 September 2002. This sym- sium was the seventh in a series of FTRTFT symposia devoted to problems and solutions in safe system design. The previous symposia took place in Warwick 1990, Nijmegen 1992, Lub ̈ eck 1994, Uppsala 1996, Lyngby 1998, and Pune 2000. Proceedings of these symposia were published as volumes 331, 571, 863, 1135, 1486, and 1926 in the LNCS series by Springer-Verlag. This year the sym- sium was co-sponsored by IFIP Working Group 2.2 on Formal Description of Programming Concepts. The symposium presented advances in the development and use of formal techniques in the design of real-time, hybrid, fault-tolerant embedded systems, covering all stages from requirements analysis to hardware and/or software - plementation. Particular emphasis was placed on UML-based development of real-time systems. Through invited presentations, links between the dependable systems and formal methods research communities were strengthened. With the increasing use of such formal techniques in industrial settings, the conference aimed at stimulating cross-fertilization between challenges in industrial usages of formal methods and advanced research. Inresponsetothecallforpapers,39submissionswerereceived.Eachsubm- sion was reviewed by four program committee members assisted by additional referees. At the end of the reviewing process, the program committee accepted 17 papers for presentation at the symposium.
Download or read book Development and Analysis of the Software Implemented Fault Tolerance SIFT Computer written by and published by . This book was released on 1984 with total page 220 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Formal Techniques Modelling and Analysis of Timed and Fault Tolerant Systems written by Yassine Lakhnech and published by Springer Science & Business Media. This book was released on 2004-09-20 with total page 405 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book constitutes the refereed proceedings of the joint International Conferences Formal Modeling and Analysis of Timed Systems, FORMATS 2004, and Formal Techniques in Real-Time and Fault-Tolerant Systems, FTRTFT 2004, held in Grenoble, France, in September 2004. The 24 revised full papers presented together with abstracts of 2 invited talks were carefully reviewed and selected from 70 submissions. Among the topics addressed are formal verification, voting systems, formal specification, dependable automation systems, model checking, timed automata, real-time testing, fault-tolerance protocols, fail-safe fault tolerance, real-time scheduling, satisfiability checking, symbolic model checking, stochastic hybrid systems, timed Petri nets, and event recording automata.
