The role of an asynchronous communication 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 synchrono ...

the transfer of

data Data ( , ) are a collection of discrete or continuous values that convey information, describing the quantity, quality, fact, statistics, other basic units of meaning, or simply sequences of symbols that may be further interpreted for ...

in a system between a

writing Writing is the act of creating a persistent representation of language. A writing system includes a particular set of symbols called a ''script'', as well as the rules by which they encode a particular spoken language. Every written language ...

process and a

reading Reading is the process of taking in the sense or meaning of symbols, often specifically those of a written language, by means of Visual perception, sight or Somatosensory system, touch. For educators and researchers, reading is a multifacete ...

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 Buffer may refer to: Science * Buffer gas, an inert or nonflammable gas * Buffer solution, a solution used to prevent changes in pH * Lysis buffer, in cell biology * Metal ion buffer * Mineral redox buffer, in geology Technology and engineeri ...

between processes (e.g., a

Unix Unix (, ; trademarked as UNIX) is a family of multitasking, multi-user 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 The Secure Shell Protocol (SSH Protocol) is a cryptographic network protocol for operating network services securely over an unsecured network. Its most notable applications are remote login and command-line execution. SSH was designed for Un ...

, 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 valu ...

does not need to be synchronised with the input). If it is necessary to

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'' * '' Inter ...

with the two systems, and make active decisions on how to handle each

packet Packet may refer to: * A small container or pouch ** Packet (container), a small single use container ** Cigarette packet ** Sugar packet * Network packet, a formatted unit of data carried by a packet-mode computer network * Packet radio, a form ...

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

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Description

References

See also