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Snapshot Algorithm
A snapshot algorithm is used to create a consistent snapshot of the global state of a distributed system. Due to the lack of globally shared memory and a global clock, this is not trivially possible. Example Several computers work together in a distributed system. Each of them represents a bank account holding a certain amount of money. The participants can transfer money between their accounts by exchanging the messages. Assume the overall balance shall be calculated. Just requesting the balance of each participant can lead to an incorrect result, if one of them just sent a transfer message to another one (and thus has already decreased its own balance), which did not yet receive it. A snapshot algorithm avoids such inconsistencies. Algorithms * Chandy–Lamport algorithm The Chandy–Lamport algorithm is a snapshot algorithm that is used in distributed systems for recording a consistent global state of an asynchronous system. It was developed by and named after Leslie La ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Distributed System
A distributed system is a system whose components are located on different networked computers, which communicate and coordinate their actions by passing messages to one another from any system. Distributed computing is a field of computer science that studies distributed systems. The components of a distributed system interact with one another in order to achieve a common goal. Three significant challenges of distributed systems are: maintaining concurrency of components, overcoming the lack of a global clock, and managing the independent failure of components. When a component of one system fails, the entire system does not fail. Examples of distributed systems vary from SOA-based systems to massively multiplayer online games to peer-to-peer applications. A computer program that runs within a distributed system is called a distributed program, and ''distributed programming'' is the process of writing such programs. There are many different types of implementations for t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chandy–Lamport Algorithm
The Chandy–Lamport algorithm is a snapshot algorithm that is used in distributed systems for recording a consistent global state of an asynchronous system. It was developed by and named after Leslie Lamport and K. Mani Chandy. Leslie Lamport, K. Mani Chandy''Distributed Snapshots: Determining Global States of a Distributed System'' In: ''ACM Transactions on Computer Systems 3''. Nr. 1, Februar 1985.PDF; 1 MB History According t “The distributed snapshot algorithm described here came about when I visited Chandy, who was then at the University of Texas in Austin. He posed the problem to me over dinner, but we had both had too much wine to think about it right then. The next morning, in the shower, I came up with the solution. When I arrived at Chandy's office, he was waiting for me with the same solution.” Definition The assumptions of the algorithm are as follows: * There are no failures and all messages arrive intact and only once * The communication channels are uni ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
