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Berkeley Algorithm
The Berkeley algorithm is a method of clock synchronisation in distributed computing which assumes no machine has an accurate time source. It was developed by Gusella and Zatti at the University of California, Berkeley in 1989. Like Cristian's algorithm, it is intended for use within intranets. The algorithm Unlike Cristian's algorithm, the server process in the Berkeley algorithm, called the ''leader'', periodically polls other ''follower'' processes. Generally speaking, the algorithm is: # A ''leader'' is chosen via an leader election, election process such as Chang and Roberts algorithm. # The ''leader'' polls the ''followers'' who reply with their time in a similar way to Cristian's algorithm. # The ''leader'' observes the round-trip time (RTT) of the messages and estimates the time of each ''follower'' and its own. # The ''leader'' then averages the clock times, ignoring any values it receives far outside the values of the others. # Instead of sending the updated current tim ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Clock Synchronisation
Clock synchronization is a topic in computer science and engineering that aims to coordinate otherwise independent clocks. Even when initially set accurately, real clocks will differ after some amount of time due to clock drift, caused by clocks counting time at slightly different rates. There are several problems that occur as a result of clock rate differences and several solutions, some being more acceptable than others in certain contexts. Terminology In serial communication, clock synchronization can refer to clock recovery which achieves frequency synchronization, as opposed to full phase synchronization. Such clock synchronization is used in synchronization in telecommunications and automatic baud rate detection. Plesiochronous or isochronous operation refers to a system with frequency synchronization and loose constraints on phase synchronization. Synchronous operation implies a tighter synchronization based on time perhaps in addition to frequency. Problems As a result ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |