Asynchrony (computer programming): Difference between revisions

Revision as of 20:29, 21 December 2017

Revision as of 21:02, 28 December 2017

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{{merge from|Asynchronous method dispatch|date=January 2016}}

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'''Asynchrony''', in [[computer programming]], refers to the occurrence of events independent of the main [[control flow|program flow]] and ways to deal with such events. These may be "outside" events such as the arrival of [[Unix signal|signals]], or actions instigated by a program that take place [[concurrent computing|concurrently]] with program execution, without the program ''blocking'' to wait for results.<ref name="davies">{{cite book |title=Async in C# 5.0 |first=Alex |last=Davies |publisher=O'Reilly |year=2012 |pages=1–2 |url=https://books.google.com/books?id=xT45qhFrVnUC}}</ref> [[Asynchronous I/O|Asynchronous input/output]] is an example of the latter cause of asynchrony, and lets programs issue commands to storage or network devices that service these requests while the [[Central processing unit|processor]] continues executing the program. Doing so provides a degree of [[parallel computing|parallelism]].{{r|davies}}

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| accessdate=19 June 2008

}}</ref> is a set of [[web development]] techniques utilizing many web technologies used on the [[client-side]] to create asynchronous I/O [[Web application]]s.

* [['''Asynchronous method dispatch]]''' (AMD), a data communication method used when there is a need for the server side to handle a large number of long lasting client requests.<ref>[https://web.archive.org/web/20130721031512/http://zeroc.com/doc/Ice-3.3.0/manual/Overview.3.2.html ICE usage of AMD].</ref> Using synchronous method dispatch (SMD), this scenario may turn the server into an unavailable busy state resulting in a connection failure response caused by a [[Computer network|network]] connection request [[Timeout (computing)|timeout]]. The servicing of a client request is immediately dispatched to an available [[thread (computer science)|thread]] from a [[Thread pool pattern|pool of threads]] and the client is put in a blocking state. Upon the completion of the task, the server is notified by a callback. The server unblocks the client and transmits the response back to the client. In case of thread starvation, clients are blocked waiting for threads to become available.

==References==

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[[Category:Computer programming]]

[[Category:Inter-process communication]]

[[Category:Middleware]]

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