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Gbcast
Gbcast (also known as group broadcast) is a reliable multicast protocol that provides ordered, fault-tolerant (all-or-none) message delivery in a group of receivers within a network of machines that experience crash failure. The protocol is capable of solving Consensus in a network of unreliable processors, and can be used to implement state machine replication. Gbcast can be used in a standalone manner, or can support the virtual synchrony execution model, in which case Gbcast is normally used for group membership management while other, faster, protocols are often favored for routine communication tasks. History Introduced in 1985, Gbcast was the first widely deployed reliable multicast protocol to implement state machine replication with dynamically reconfigurable membership. Although this problem had been treated theoretically under various models in prior work, Gbcast innovated by showing that the same multicasts used to update replicated data within the state machine can also ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paxos (computer Science)
Paxos is a family of protocols for solving consensus in a network of unreliable or fallible processors. Consensus is the process of agreeing on one result among a group of participants. This problem becomes difficult when the participants or their communications may experience failures. Consensus protocols are the basis for the state machine replication approach to distributed computing, as suggested by Leslie Lamport and surveyed by Fred Schneider. State machine replication is a technique for converting an algorithm into a fault-tolerant, distributed implementation. Ad-hoc techniques may leave important cases of failures unresolved. The principled approach proposed by Lamport et al. ensures all cases are handled safely. The Paxos protocol was first submitted in 1989 and named after a fictional legislative consensus system used on the Paxos island in Greece, where Lamport wrote that the parliament had to function "even though legislators continually wandered in and out of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Virtual Synchrony
Reliable multicast is any computer networking protocol that provides a '' reliable'' sequence of packets to multiple recipients simultaneously, making it suitable for applications such as multi-receiver file transfer. Overview Multicast is a network addressing method for the delivery of information to a group of destinations simultaneously using the most efficient strategy to deliver the messages over each link of the network only once, creating copies only when the links to the multiple destinations split (typically network switches and routers). However, like the User Datagram Protocol, multicast does not guarantee the delivery of a message stream. Messages may be dropped, delivered multiple times, or delivered out of order. A reliable multicast protocol adds the ability for receivers to detect lost and/or out-of-order messages and take corrective action (similar in principle to TCP), resulting in a gap-free, in-order message stream. Reliability The exact meaning of ''r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ACM Symposium On Principles Of Distributed Computing
The ACM Symposium on Principles of Distributed Computing (PODC) is an academic conference in the field of distributed computing organised annually by the Association for Computing Machinery (special interest groups SIGACT and SIGOPS). Scope and related conferences Work presented at PODC typically studies theoretical aspects of distributed computing, such as the design and analysis of distributed algorithms. The scope of PODC is similar to the scope of International Symposium on Distributed Computing (DISC), with the main difference being geographical: DISC is usually organized in European locations,DISC in . while PODC has been traditionally held in North America. [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Communications Of The ACM
''Communications of the ACM'' (''CACM'') is the monthly journal of the Association for Computing Machinery (ACM). History It was established in 1958, with Saul Rosen as its first managing editor. It is sent to all ACM members. Articles are intended for readers with backgrounds in all areas of computer science and information systems. The focus is on the practical implications of advances in information technology and associated management issues; ACM also publishes a variety of more theoretical journals. The magazine straddles the boundary of a science magazine, trade magazine, and a scientific journal. While the content is subject to peer review, the articles published are often summaries of research that may also be published elsewhere. Material published must be accessible and relevant to a broad readership. From 1960 onward, ''CACM'' also published algorithms, expressed in ALGOL. The collection of algorithms later became known as the Collected Algorithms of the ACM. CA ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Journal Of The Association For Computing Machinery
The ''Journal of the ACM'' (''JACM'') is a peer-reviewed scientific journal covering computer science in general, especially theoretical aspects. It is an official journal of the Association for Computing Machinery. Its current editor-in-chief is Venkatesan Guruswami. The journal was established in 1954 and "computer scientists universally hold the ''Journal of the ACM'' in high esteem". See also * ''Communications of the ACM ''Communications of the ACM'' (''CACM'') is the monthly journal of the Association for Computing Machinery (ACM). History It was established in 1958, with Saul Rosen as its first managing editor. It is sent to all ACM members. Articles are i ...'' References External links * {{DEFAULTSORT:Journal Of The Acm Academic journals established in 1954 Computer science journals Association for Computing Machinery academic journals Bimonthly journals English-language journals ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Safety And Liveness Properties
Properties of an execution of a computer program—particularly for concurrent and distributed systems—have long been formulated by giving safety properties ("bad things don't happen") and liveness properties ("good things do happen"). A program is totally correct with respect to a precondition P and postcondition Q if any execution started in a state satisfying P terminates in a state satisfying Q. Total correctness is a conjunction of a safety property and a liveness property: * The safety property prohibits these "bad things": executions that start in a state satisfying P and terminate in a final state that does not satisfy Q. For a program C, this safety property is usually written using the Hoare triple \ C \. * The liveness property, the "good thing", is that execution that starts in a state satisfying P terminates. Note that a ''bad thing'' is discrete, since it happens at a particular place during execution. A "good thing" need not be discrete, but the liveness propert ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reliable Multicast
Reliable multicast is any computer networking protocol that provides a '' reliable'' sequence of packets to multiple recipients simultaneously, making it suitable for applications such as multi-receiver file transfer. Overview Multicast is a network addressing method for the delivery of information to a group of destinations simultaneously using the most efficient strategy to deliver the messages over each link of the network only once, creating copies only when the links to the multiple destinations split (typically network switches and routers). However, like the User Datagram Protocol, multicast does not guarantee the delivery of a message stream. Messages may be dropped, delivered multiple times, or delivered out of order. A reliable multicast protocol adds the ability for receivers to detect lost and/or out-of-order messages and take corrective action (similar in principle to TCP), resulting in a gap-free, in-order message stream. Reliability The exact meaning of ''rel ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atomic Broadcast
In fault-tolerant distributed computing, an atomic broadcast or total order broadcast is a broadcast where all correct processes in a system of multiple processes receive the same set of messages in the same order; that is, the same sequence of messages. The broadcast is termed " atomic" because it either eventually completes correctly at all participants, or all participants abort without side effects. Atomic broadcasts are an important distributed computing primitive. Properties The following properties are usually required from an atomic broadcast protocol: # Validity: if a correct participant broadcasts a message, then all correct participants will eventually receive it. # Uniform Agreement: if one correct participant receives a message, then all correct participants will eventually receive that message. # Uniform Integrity: a message is received by each participant at most once, and only if it was previously broadcast. # Uniform Total Order: the messages are totally order ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Consensus (computer Science)
A fundamental problem in distributed computing and multi-agent systems is to achieve overall system reliability in the presence of a number of faulty processes. This often requires coordinating processes to reach consensus, or agree on some data value that is needed during computation. Example applications of consensus include agreeing on what transactions to commit to a database in which order, state machine replication, and atomic broadcasts. Real-world applications often requiring consensus include cloud computing, clock synchronization, PageRank, opinion formation, smart power grids, state estimation, control of UAVs (and multiple robots/agents in general), load balancing, blockchain, and others. Problem description The consensus problem requires agreement among a number of processes (or agents) on a single data value. Some of the processes (agents) may fail or be unreliable in other ways, so consensus protocols must be fault-tolerant or resilient. The processes must p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
State Machine Replication
In computer science, state machine replication (SMR) or state machine approach is a general method for implementing a fault-tolerant service by replicating servers and coordinating client interactions with server replicas. The approach also provides a framework for understanding and designing replication management protocols. Problem definition Distributed service In terms of clients and services, each service comprises one or more servers and exports operations that clients invoke by making requests. Although using a single, centralized server is the simplest way to implement a service, the resulting service can only be as fault tolerant as the processor executing that server. If this level of fault tolerance is unacceptable, then multiple servers that fail independently can be used. Usually, replicas of a single server are executed on separate processors of a distributed system, and protocols are used to coordinate client interactions with these replicas. State machine For the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transmission Control Protocol
The Transmission Control Protocol (TCP) is one of the main communications protocol, protocols of the Internet protocol suite. It originated in the initial network implementation in which it complemented the Internet Protocol (IP). Therefore, the entire suite is commonly referred to as TCP/IP. TCP provides reliability (computer networking), reliable, ordered, and error detection and correction, error-checked delivery of a reliable byte stream, stream of octet (computing), octets (bytes) between applications running on hosts communicating via an IP network. Major internet applications such as the World Wide Web, email, remote administration, and file transfer rely on TCP, which is part of the transport layer of the TCP/IP suite. Transport Layer Security, SSL/TLS often runs on top of TCP. TCP is Connection-oriented communication, connection-oriented, meaning that sender and receiver firstly need to establish a connection based on agreed parameters; they do this through three-way Ha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vanilla (software)
Vanilla software refers to applications and systems used in their unmodified, original state, as distributed by their vendors. This term is often applied in fields such as enterprise resource planning (ERP), e-government systems,Clohessy, Trevor; Acton, Thomas, (2013) "Enterprise Resource Planning for e-Government in the Cloud." Presented at the 2nd International Conference of Informatics and Management Sciences, University of Limerick, pp. 467 – 469. and software development, where simplicity and adherence to vendor standards are more important than expanded functionality. By opting for vanilla software, organizations benefit from lower costs and straightforward maintenance, though the trade-off may include reduced flexibility and customization options. The term "vanilla" has become ubiquitous in computing and technology to describe configurations or implementations that lack customization. In these contexts, it emphasizes simplicity, standardization, and ease of maintenance. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
