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Reliable Distributed Systems, 1993. Proceedings., 12th Symposium on

Date 6-8 Oct. 1993

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Displaying Results 1 - 16 of 16
  • Proceedings of 1993 IEEE 12th Symposium on Reliable Distributed Systems

    Publication Year: 1993
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    Freely Available from IEEE
  • An approach to constructing modular fault-tolerant protocols

    Publication Year: 1993 , Page(s): 105 - 114
    Cited by:  Papers (5)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (992 KB)  

    Modularization is a well-known technique for simplifying complex software. An approach to modularizing fault-tolerant protocols such as reliable multicast and membership is described. The approach is based on implementing a protocol's individual properties as separate microprotocols and then combining selected microprotocols using an event-driven software framework. A system is constructed by composing these frameworks with traditional network protocols using standard hierarchical techniques. In addition to simplifying the software, this model helps clarify the dependencies among properties of fault-tolerant protocols and makes it possible to construct systems that are customized to the specifics of the application or underlying architecture. An example involving reliable group multicast is given, together with a description of a prototype implementation using the SR concurrent programming language View full abstract»

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  • A secure two phase locking protocol

    Publication Year: 1993 , Page(s): 126 - 135
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (904 KB)  

    A secure concurrency control algorithm must, in addition to maintaining consistency of the database, be free from covert channels arising due to data conflicts between transactions. The existing secure concurrency control approaches are unfair to transactions at higher access classes. A secure two-phase locking protocol that is shown to be free from covert channels arising due to data conflicts between transactions and that provides reasonably fair execution of all transactions, regardless of their access class, is presented. A description of the protocol for a centralized database system is given, and the extensions that need to be provided in a distributed environment are discussed View full abstract»

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  • Bayesian analysis for fault location in homogeneous distributed systems

    Publication Year: 1993 , Page(s): 44 - 53
    Cited by:  Papers (4)  |  Patents (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (832 KB)  

    A simple and practical probabilistic comparison-based model, employing multiple incomplete test concepts, for handling fault location in distributed systems using a Bayesian analysis procedure is proposed. This approach is more practical and complete than previous ones since it does not assume any conditions such as permanently faulty units, complete tests, perfect environments, or non-malicious environments. Fault-free systems are handled without overhead; hence, the test procedure may be used to monitor a functioning system. Given a system S with a specific test graph, the corresponding conditional distribution between the comparison test results (syndrome) and the fault patterns of S can be generated. To avoid the complex global Bayesian estimation process, a simple bitwise Bayesian algorithm is developed for fault location in S, which locates system failures with linear complexity, suitable for hard real-time systems View full abstract»

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  • An O(1) quorum consensus protocol tailored for the client/server architecture

    Publication Year: 1993 , Page(s): 98 - 104
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    In a client/server architecture, replicated copies of an object are assigned to different servers (possibly client sites) in order to increase the availability of the database in case some but not all servers fail. A highly efficient, highly reliable quorum consensus protocol, the Quorum Rings protocol (QRP), specifically designed to take advantage of the client/server architecture, is introduced. The high resiliency of QRP is achieved at a very low cost in communication messages. More specifically, the number of communication messages required for a QRP read or write operation is O(1) in normal mode (when there are no failures in the system) and only O(√N) in failure mode (when some but not all servers with replicated objects are faulty). Finally, QRP exhibits the property of graceful degradation: more communication cost is incurred only when the number of failures increases in the system View full abstract»

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  • Rollback based on vector time

    Publication Year: 1993 , Page(s): 68 - 77
    Cited by:  Papers (6)
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    Causality, as made concrete by Lamport's "happened before" relation, is the central underlying basis in the design of optimistic protocols for checkpoint and recovery. After the recovery of a formerly failed process, all events and messages which causally follow the events and messages discarded by restoration of a state checkpoint must be discarded also. The isomorphism between causality and vector time is well-known. That isomorphism is exploited here in order to develop and verify a simple and effective protocol which explicitly uses the causal partial order, through the use of vector time, in order to rollback a computation in response to a process failure View full abstract»

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  • Lazy checkpoint coordination for bounding rollback propagation

    Publication Year: 1993 , Page(s): 78 - 85
    Cited by:  Papers (26)  |  Patents (8)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (716 KB)  

    The technique of lazy checkpoint coordination, which preserves process autonomy while employing communication-induced checkpoint coordination for bounding rollback propagation is proposed. The notion of laziness is introduced to control the coordination frequency and allow a flexible tradeoff between the cost of checkpoint coordination and the average rollback distance. Worst-case overhead analysis provides a means for estimating the extra checkpoint overhead. Communication trace-driven simulation for several parallel programs is used to evaluate the benefits of the proposed scheme View full abstract»

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  • Efficient transparent optimistic rollback recovery for distributed application programs

    Publication Year: 1993 , Page(s): 86 - 95
    Cited by:  Papers (21)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1204 KB)  

    A transparent rollback-recovery method that adds very little overhead to distributed application programs and efficiently supports the quick commit of all output to the outside world is introduced. Each process can independently choose at any time either to use checkpointing alone (as in consistent checkpointing) or to use optimistic message logging. The system is based on a new commit algorithm that requires communication with and information about the minimum number of other processes in the system, and supports the recovery of both deterministic and nondeterministic processes View full abstract»

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  • Using atomic broadcast to implement a posteriori agreement for clock synchronization

    Publication Year: 1993 , Page(s): 115 - 124
    Cited by:  Papers (2)
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    A clock synchronization algorithm was given by P. Verissimo et al. (1989), dubbed a posteriori agreement, a variant of the convergence nonaveraging technique. By exploiting the characteristics of broadcast networks, the effect of message delivery delay variance is largely reduced. In consequence, the precision achieved by the algorithm is drastically improved. Accuracy preservation is near to optimal. A particular materialization of this algorithm, implemented as a time service of the xAMp group communications system, is given here. The algorithm was implemented using some of the primitives offered by xAMp, which simplified the work and stressed its advantages. Performance results for this implementation obtained on two different infrastructures are presented. Timings validate the design choices and clearly show that the algorithm is able to provide improved precision without compromising accuracy and reliability View full abstract»

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  • Some remarks on protecting weak keys and poorly-chosen secrets from guessing attacks

    Publication Year: 1993 , Page(s): 136 - 141
    Cited by:  Papers (3)  |  Patents (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (644 KB)  

    Authentication and key distribution protocols that utilize weak secrets (such as passwords and personal identification numbers) are traditionally susceptible to guessing attacks whereby an adversary iterates through a relatively small key space and verifies the correct guess. Such attacks can be defeated by the use of public key encryption and careful protocol construction. T. Lomas et al. (Proc. of ACM Symp. on Operating Syst. Principles, 1989) investigated this topic and developed a methodology for avoiding guessing attacks while incurring only moderate overhead. Several issues concerning the proposed solution are discussed here, and modifications that remove some of the constraints (such as synchronized time and state retention by the server) and result in simpler and more efficient protocols are suggested View full abstract»

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  • A compositional proof theory for fault tolerant real-time distributed systems

    Publication Year: 1993 , Page(s): 34 - 43
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (716 KB)  

    A compositional network proof theory for specifying and verifying fault tolerant real-time distributed systems is presented. Important in such systems is the failure hypothesis that stipulates the class of failures that must be tolerated. In the formalism presented, the failure hypothesis of a system is represented by a predicate which expresses how faults might transform the behavior of the system. The approach is illustrated by investigating a triple modular redundant system View full abstract»

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  • Processor group membership protocols: specification, design and implementation

    Publication Year: 1993 , Page(s): 2 - 11
    Cited by:  Papers (19)  |  Patents (11)
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    The specification, design and implementation of a set of protocols to solve the processor group membership problem in distributed systems are presented. These group membership protocols were developed as part of a toolkit for building distributed/parallel applications on a cluster of workstations. The group membership service forms the lowest layer in the toolkit, and is the glue which unifies all other layers. The membership service supports three distinct protocols: weak, strong, and hybrid. These protocols differ significantly in the level of consistency and the number of messages exchanged in reaching agreement. The modular implementation of these protocols and the optimization techniques used to enhance their performance are described View full abstract»

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  • Constructing secure distributed systems using components

    Publication Year: 1993 , Page(s): 143 - 152
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    Current hookup theories may impose overstrong security requirements on component systems. To overcome this problem, connectivities of the components may have to be considered in order to appropriately handle their composition. Such a consideration is used here to describe composable security properties. Security requirements are enforced only on some input and output entities of each component with regard to its connectivity, and communication constraints on its others so as to ensure that their entire system can satisfy its security requirement. This enables the system and its components to possess different security properties, i.e., the security property of the system can be logically stronger than security properties of its components View full abstract»

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  • APRICOTS a prototype implementation of a ConTract system: management of the control flow and the communication system

    Publication Year: 1993 , Page(s): 12 - 21
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    The principle of transactions has been proven in the field of database systems. However, there are many fields where classical transactions are not suitable to model the actions of the real world. An approach to extend the principle of transactions is the ConTract model, which weakens some demands of the ACID-principle but at the same time includes other features. An approach to implement a ConTract system is introduced. Especially, the implementation issues of a component for reliable control flow management and of a transaction-oriented communication system are discussed View full abstract»

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  • Using logging and asynchronous checkpointing to implement recoverable distributed shared memory

    Publication Year: 1993 , Page(s): 58 - 67
    Cited by:  Papers (23)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (856 KB)  

    Distributed shared memory provides a useful paradigm for developing distributed applications. As the number of processors in the system and running time of distributed applications increase, the likelihood of processor failure increases. A method of recovering processes running in a distributed shared memory environment which minimizes lost work and the cost of recovery is desirable so that long-running applications are not adversely affected by processor failure. A technique for achieving recoverable distributed shared memory which utilizes asynchronous process checkpoints and logging of pages accessed via read operations on the shared address space is presented. The scheme supports independent process recovery without forcing rollback of operational processes during recovery. The method is particularly useful in environments where taking process checkpoints is expensive View full abstract»

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  • An approach for combinatorial performance and availability analysis

    Publication Year: 1993 , Page(s): 24 - 33
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    The common approach to formulating and solving combined reliability/availability and performance problems is to use Markov reward models. However, the large size of state spaces is a problem that plagues Markovian models. Combinatorial models have been used for modeling reliability and availability of complex systems without paying the price of large Markov models. Yet, assumptions of two-state behavior of components (and that of the system), independence assumptions of component failure behavior, and restrictive repair assumptions decrease the potential of combinatorial models for realistic systems. A combinatorial approach is proposed for the combined performance and availability analysis of coherent repairable systems with multi-state components, allowing inter-dependent component state transitions. Examples showing the usefulness of the approach are presented View full abstract»

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