The role of an
asynchronous communication
In telecommunications, 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 f ...
mechanism (ACM) is to
synchronize
Synchronization is the coordination of events to operate a system in unison. For example, the conductor of an orchestra keeps the orchestra synchronized or ''in time''. Systems that operate with all parts in synchrony are said to be synchronou ...
the transfer of
data
In the pursuit of knowledge, data (; ) is a collection of discrete values that convey information, describing quantity, quality, fact, statistics, other basic units of meaning, or simply sequences of symbols that may be further interpret ...
in a system between a
writing
Writing is a medium of human communication which involves the representation of a language through a system of physically Epigraphy, inscribed, Printing press, mechanically transferred, or Word processor, digitally represented Symbols (semiot ...
process and a
reading
Reading is the process of taking in the sense or meaning of Letter (alphabet), letters, symbols, etc., especially by Visual perception, sight or Somatosensory system, touch.
For educators and researchers, reading is a multifaceted process invo ...
process operating concurrently.
Description
The mechanism by which the ACM performs its tasks varies heavily depending upon the situation in which the ACM is employed. A possible scenario is the writer outputs data at a higher rate than the reader can process it. Without an ACM, one of two things will happen:
*If the system incorporates a
buffer between processes (e.g., a
Unix
Unix (; trademarked as UNIX) is a family of multitasking, multiuser computer operating systems that derive from the original AT&T Unix, whose development started in 1969 at the Bell Labs research center by Ken Thompson, Dennis Ritchie, a ...
shell pipe), then data will accumulate and be processed at the reader's maximum rate. There are some circumstances in which this is a desirable characteristic (e.g. piping a file over
SSH, or if all data in the set is important, and the reader's
output
Output may refer to:
* The information produced by a computer, see Input/output
* An output state of a system, see state (computer science)
* Output (economics), the amount of goods and services produced
** Gross output in economics, the value ...
does not need to be synchronised with the
input).
If it is necessary to
synchronize
Synchronization is the coordination of events to operate a system in unison. For example, the conductor of an orchestra keeps the orchestra synchronized or ''in time''. Systems that operate with all parts in synchrony are said to be synchronou ...
the input of the writer with the output of the reader, then the ACM can
interface
Interface or interfacing may refer to:
Academic journals
* ''Interface'' (journal), by the Electrochemical Society
* '' Interface, Journal of Applied Linguistics'', now merged with ''ITL International Journal of Applied Linguistics''
* '' Int ...
with the two systems, and make active decisions on how to handle each
packet of information. If, for example, maximum synchronization is required, the ACM could be configured to drop packets, and output the newest packets at the reader's maximum speed.
Alternatively, if there is no buffer, some data may be lost. If this is undesirable, the ACM can provide this buffer, or process the data in such a way that minimal information is lost.
References
{{reflist
See also
*
System
*
Rate
Computer-mediated communication
Synchronization