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Group communication
A multicast operation is more appropriate – this is an operation that sends a single message from one process to each of the members of a group of processes, usually in such a…
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Global Name Service (GNS)
Designed and implemented by Lampson and colleagues at the DEC Systems Research Center (1986) Provide facilities for resource location, email addressing and authentication When the naming database grows from small…
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Synchronizing physical clocks
Two models of synchronization 1) External synchronization 2) Internal synchronization External synchronization: a computer‘s clock Ci is synchronized with an external authoritative time source S, so that: |S(t) - Ci(t)| < D for i = 1, 2, …N over an interval, I of…
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CLOCKS, EVENTS AND PROCESS STATES
Each process executes on a single processor, and the processors do not share memory (Chapter 6 briefly considered the case of processes that share memory). Each process pi in has a state si that,…
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Physical, Logical, and Vector Clocks
Interactions within a Distributed System between 2 processes, P1 and P2. Distributed systems offer us the ability to solve problems we couldn’t possibly solve with a single machine. However, I…
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Global States
It is often desirable to determine whether a particular property is true of a distributed system as it executes. We'd like to use logical time to construct a global view…
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distributed computing
Distributed computing is a model in which components of a software system are shared among multiple computers to improve efficiency and performance. According to the narrowest of definitions, distributed computing…
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Design Issues of Distributed System
The distributed information system is defined as “a number of interdependent computers linked by a network for sharing information among them”. A distributed information system consists of multiple autonomous computers…
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Synchronous vs Asynchronous
The send, receive, and reply operations may be synchronous or asynchronous. A synchronous operation blocks a process till the operation completes. An asynchronous operation is non-blocking and only initiates the operation. The caller could discover completion by some other mechanism discussed later. (Does…
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Message Passing Model of Process Communication
Process communication is the mechanism provided by the operating system that allows processes to communicate with each other. This communication could involve a process letting another process know that some…