asynchronous

Asynchronous communication is transmission of data, generally without the use of an external clock signal, where data can be transmitted intermittently rather than in a steady stream. Any timing required to recover data from the communication symbols is encoded within the symbols. The most significant aspect of asynchronous communications is that data is not transmitted at regular intervals, thus making possible variable bit rate, and that the transmitter and receiver clock generators do not have to be exactly synchronized all the time.

Think of the ways that you communicate with others. There are synchronous methods such as speaking face to face as in a meeting or speaking on the telephone. These methods require all participants to active in the conversation at the same moment all others are active. Traffic is a synchronous method. All drivers active on the roads are engaged at all times. While this gives great flexibility at low volumes, it can lead to stunning levels of chaos once traffic levels rise.

Asynchronous methods of communication include text messaging, email, voice mail, letters, notes, Facebook, and many others. These methods do NOT require all participants to be active simultaneously. Asynchronous methods indeed are the primary form of communication for modern business, but not for software development! Most systems are built not only with the monolithic techniques that I rail against in this wiki, but also using almost solely synchronous methods, even where asynchronous methods are available and would make a better choice! Similar to traffic patterns, asynchronous methods become increasingly more effective compared to synchronous methods as contention for resources increases. You can find many articles here; search for "asynchronous".

With the advent of SQL Service Broker there seems little justification for not de-coupling a SQL application. You may think of this in terms of a workflow or job scheduling application. Each step in the workflow can run independently of the remainder, pushing the next onto the job queue when it finishes rather than calling it synchronously (see Mediator pattern).

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copyright Katherine Elizabeth Lightsey 1959-2013 (aka; my life)

"There are only two symptoms of enlightenment. The first symptom is that you stop worrying, become light-hearted and full of joy. The second symptom is that you encounter more and more meaningful coincidences in your life, more and more synchronicities. This accelerates to the point where you actually experience the miraculous. (quoted by Carol Lynn Pearson in Consider the Butterfly) - Deepak Chopra, Synchrodestiny: Harnessing the Infinite Power of Coincidence to Create Miracles