Middleware marks application-independent technologies, which offer services for the switching between applications in computer science, so that the complexity of the underlying applications and infrastructure is hidden (after W. rest among other things: Enterprise Application integration, Wiley, 2001). One knows middleware also as a distribution platform, i.e. when usual computer communication understand minutes (or minutes bundles) on a higher layer than that.

Middleware represents one level in a complex software system, which makes other otherwise decoupled software components possible communication as "Dienstleister "among themselves. Usually this communication takes place with the help of a network, which is made by the middleware for the software components transparency using it. Middleware works at it on a high level within the layer model: Their task is thus not Low level communication for individual bytes (like it for example already an operating system makes available). Middleware organizes the transport of complex data (so-called Messaging), obtains function calls between the components (so-called remote Procedure call), places transaction security over otherwise independent subsystems ago (function as transaction monitor) to etc.

Middleware software is available as standard software of several manufacturers. Technically it makes available to software interfaces and/or services. A software component A, which would like to use the middleware layer, in order to communicate with a software component B, can use these interfaces. Appropriate calls by the middleware software component over a network are passed on (usually common network standard minutes become (nearly always TCP/IP, whereupon constructing usually HTTP, whereupon constructing SOAP, Web services uses among other things). On the receiver side the middleware converts the requirement into a function call to the software B. If necessary it returns "the answer "of the component B at component A on the same way.

As disadvantage of middleware its size and ponderousness can be called. An optimization of the efficiency of these programs is often hardly possible by the programmer.

Middleware categories

A rough partitioning to assist in the understanding:

• Communication-oriented middleware

Here the emphasis lies in the abstraction of network programming.

e.g.: Java of RMI, Web service

• Application orientated middleware

In the center above all the support of distributed applications is located apart from communication.

Examples are both general architectures, and CORBA, J2EE or .NET, and complete operating systems, like e.g.

• MIDP (mobile information DEVICE of profiles), Java based system for mobile telephones,
• MHP (Multimedia Home Platform), Java based system for the interactive television.

Typical middleware products

• CICS of IBM
• SAP Exchange Infrastructure of SAP
• Visibroker (boron country)
• ObjectBroker of BEA of system, Inc., (Object Request broker)
• WebSphere Application server by IBM, (J2EE server)
• MQSeries of IBM
• Transparency inter Process Communication (open SOURCE, originally developed by Ericsson)
• Common Object Request broker Architecture briefly CORBA of the Object management Group (OMG)

See also

Distributed systems, system software, data base system, DCE, CORBA, DCOM, .NET, ODBC, IIOP, RPC, RMI

Related links

• ObjectWeb (English)
• Middleware.org (English) property overview of middleware products

Articles in category "Middleware"

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