Intergiciel

In Data-processing, a intergiciel (in English middleware ) is a Logiciel being used as intermediary of communication between several applications, generally complexes or distributed on a Data-processing network.

Vocabulary

The term middleware comes from the English middle (of the medium) and software (software). Various Francizations were proposed, but their use remains confidential:

the General delegation with the French language and the languages of France (DGLF) recommends the use of software mediator since 1999.
the Québécois Office of the French language (OQLF), as for him, proposes the terms software transition courses and intergiciel .
the terms of software of intermediation and, by abuse software language, drunk (see also Data bus) can be met in the literature.

Description

The middleware offers high level services related to the needs for communication of the applications (real-time, security, serialization, data-processing Transaction, etc)…

It is what one calls a Interprocess communication (English InterProcess Communication , IPC). It comes to be located in OSI model at the top of the Couche of transport (layers 5,6 and 7). The double mission of interfacing of the middleware is:

the process customer or waiter: the management of the calls of functions of the application or the management of the reference of the results.
working of the Given S for their assumption of responsibility by the transport layer.

The two missions are ensured by two distinct components:

the formatted Access protocol ( Format And Protocol , FAP) brings in form the various data to the level of the network.
the Application program interface ( Application Programming Interfaces , API) takes care:

of connections and disconnections with the waiter;
of the definition of the environment of connection (variables of context, buffer zones); and
of the transfer of the requests and the reception of the results (tuple by tuple or in a total way).

The application program interface transmits to the FAP the requests intended for the waiter which will be given the responsability to condition the data with transport by the network. The FAP is specific to each protocol network. The FAP of the customer receives the request and folds in a screen intended for transport on the network. The FAP of the waiter receives the screen, unfolds it and transmits the request to the interface. After treatment, the waiter returns the result of the request to the interface which will transmit to the customer via the FAP of the waiter, then of the customer, either by tuple of result, or in entirety.

Examples of middleware: EAI, LTE, CORBA, HLA, Queue of message, Fire wall, ODBC, NEXUS.

The middleware is located " with-dessous" the applicatif one, " with-dessus" operating system and " entre" two software needing to communicate between them!

For example, the couple + ODBC forms a middleware.

The middleware more sails about it in the architectures known as '' three thirds '' are:

the middleware " directed objects or component distribués" : they are the ORB or Object Request Broker
the middleware " transactionnels" : they are the compromise monitors (like CICS of IBM, Tuxedo of BEA, MTS from Microsoft, JTS of Sun, TopEnd of NCR or Jaguar of Sybase,…)
the middleware " directed messages" : they are MOM (like MQ Series from IBM, JMS of Sun, MSMQ from Microsoft).

A tendency (marketing?) also releases itself towards integration from the middleware " distribués" objects; with the " monitors transactionnels" (case of Tuxedo which amalgamates with the ORB ObjectBroker to constitute the product m3 of BEA, case also of offer COM+ from Microsoft) and to thus form a unit renamed for the occasion: waiter of application. See also EAI.

The access to the data and the services being critical for the companies, the waiters of application is supplemented by a layer of access to the data based on standards such as JDO or SDO.

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