Middleware (distributed applications): Difference between revisions

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{{short description|Provides services for the various components of a distributed system}}'''Middleware''' in the context of [[distributed application]]s is [[software]] that provides services beyond those provided by the [[operating system]] to enable the various components of a distributed system to communicate and manage data. Middleware supports and simplifies complex [[distributed application]]s. It includes [[web server]]s, [[application server]]s, messaging and similar tools that support application development and delivery. Middleware is especially integral to modern information technology based on [[XML]], [[SOAP]], [[Web service]]s, and [[service-oriented architecture]].

{{About|distributed applications|middleware in general|Middleware}}

'''Middleware''' in the context of [[distributed application]]s is [[software]] that provides services beyond those provided by the [[operating system]] to enable the various components of a distributed system to communicate and manage data. Middleware supports and simplifies complex [[distributed application]]s. It includes [[web server]]s, [[application server]]s, messaging and similar tools that support application development and delivery. Middleware is especially integral to modern information technology based on [[XML]], [[SOAP]], [[Web service]]s, and [[service-oriented architecture]].

Middleware often enables [[interoperability]] between applications that run on different operating systems, by supplying services so the application can exchange data in a standards-based way. Middleware sits "in the middle" between [[application software]] that may be working on different [[operating system]]s. It is similar to the middle layer of a [[Multitier architecture|three-tier]] single system architecture, except that it is stretched across multiple systems or applications. Examples include [[Enterprise Application Integration|EAI]] software, telecommunications software, [[Transaction Processing System|transaction monitors]], and messaging-and-queueing software.

The distinction between operating system and middleware functionality is, to some extent, arbitrary. While core kernel functionality can only be provided by the operating system itself, some functionality previously provided by separately sold middleware is now integrated in operating systems. A typical example is the [[TCP/IP]] stack for telecommunications, nowadays included in virtually in every operating system.

==Definitions==

SoftwareMiddleware is defined as software that provides a link between separate software applications. MiddlewareIt is sometimes calledreferred to as plumbing because it connects two applications and passes data between them. Middleware allows data contained in one database to be accessed through another. This definitionmakes wouldit particularly useful fitfor [[enterprise application integration]] and [[data integration]] softwaretasks.

ObjectWebIn definesmore abstract terms, middleware as:is "The software layer that lies between the [[operating system]] and applications on each side of a distributed computing system in a network."<ref>{{Cite web|first=Sacha|last=Krakowiak|url=http://middleware.objectweb.org/|title=What's middleware?|accessdateaccess-date=2005-05-06|publisher=ObjectWeb.org|deadurlurl-status=yesdead|archiveurlarchive-url=https://web.archive.org/web/20050507151935/http://middleware.objectweb.org/|archivedatearchive-date=2005-05-07|df=}}</ref>

== Origins ==

Middleware is a relatively new addition to the computing landscape. It gained popularity in the 1980s as a solution to the problem of how to link newer applications to older legacy systems, although the term had been in use since 1968.<ref>{{Cite web|first=Nick|last=Gall|url=http://ironick.typepad.com/ironick/2005/07/update_on_the_o.html|title=OriginUpdate on the origin of the term ''''"middleware"|date=July 30, 2005}}</ref> It also facilitated [[distributed processing]], the connection of multiple applications to create a larger application, usually over a network.

==Use==

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when compared to the operating system and network services.

Middleware offers some unique technological advantages for business and industry. For example, traditional database systems are usually deployed in closed environments where users access the system only via a [[restricted network]] or [[intranet]] (e.g., an enterprise’s internal network). With the phenomenal growth of the [[World Wide Web]], users can access virtually any database for which they have proper access rights from anywhere in the world. Middleware addresses the problem of varying levels of [[interoperability]] among different database structures. Middleware facilitates transparent access to legacy [[database management system]]s (DBMSs) or applications via a [[web server]] without regard to database-specific characteristics.<ref>Peng, C, Chen, S, Chung, J, Roy-Chowdhury, A, and Srinivasan, V. (1998). Accessing

existing business data from the World Wide Web. IBM Systems Journal, 37(1), 115-132.

Retrieved March 7, 2009, from ABI/INFORM Global database. (Document ID: 26217517)

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Databases. Journal of Database Management, 17(4), 20-39,41-46. Retrieved March 7,

2009, from ABI/INFORM Global database. (Document ID: 1155773301).

</ref> In the highly competitive healthcare community, laboratories make extensive use of middleware applications for [[data mining]], [[laboratory information system]] (LIS) backup, and to combine systems during hospital mergers. Middleware helps bridge the gap between separate LISs in a newly formed healthcare network following a hospital buyout.<ref>Bagwell, H. (2008). [http://www.devicelink.com/ivdt/archive/08/07/007.html Middleware: providing value beyond autoverification] {{Webarchive|url=https://web.archive.org/web/20091012130823/http://www.devicelink.com/ivdt/archive/08/07/007.html |date=2009-10-12 }}. IVDT. Retrieved March 3, 2009. .</ref>

March 3, 2009.

{{webarchive |url=https://web.archive.org/web/20091012130823/http://www.devicelink.com/ivdt/archive/08/07/007.html |date=October 12, 2009 }}</ref>

Middleware can help software developers avoid having to write [[application programming interface]]s (API) for every control program, by serving as an independent programming interface for their applications.

For [[Future Internet]] network operation through traffic monitoring in [[Network management|multi-___domain scenarios]], using mediator tools (middleware) is a powerful help since they allow [[Telecommunications service provider|operators]], searchers and [[service providers]] to supervise [[Quality of service]] and analyse eventual failures in [[telecommunication service]]s.<ref>{{Cite web|author=Kai Oswald Seidler |url=http://www.fp7-moment.eu/ |title=MOMENT |publisher=Fp7-moment.eu |access-date= |accessdate=2010-08-19}}</ref>

Finally, e-commerce uses middleware to assist in handling rapid and secure transactions over many different types of computer environments.<ref>Charles, J. (1999). [httphttps://ieeexplore.ieee.org/ielx5Xplore/2/16523/00762786login.jsp?url=%2Fielx5%2F2%2F16523%2F00762786.pdf&authDecision=-203 Middleware moves to the forefront] {{subscription required}}. Technology News. Retrieved March 2, 2009.</ref> In short, middleware has become a critical element across a broad range of industries, thanks to its ability to bring together resources across dissimilar networks or computing platforms.

2009.</ref> In short, middleware has become a critical element across a broad range of industries, thanks to its ability to bring together resources across dissimilar networks or computing platforms.

In 2004 members of the [[European Broadcasting Union]] (EBU) carried out a study of Middleware with respect to system integration in broadcast environments. This involved system design engineering experts from 10 major European broadcasters working over a 12-month period to understand the effect of predominantly software-based products to media production and broadcasting system design techniques. The resulting reports Tech 3300 and Tech 3300s were published and are freely available from the EBU web site.<ref>{{Cite web|url=http://tech.ebu.ch/docs/tech/tech3300.pdf |title=EBU middleware report Tech 3300 |format=PDF |access-date= |accessdate=2010-08-19}}</ref><ref>{{Cite web|url=http://tech.ebu.ch/docs/tech/tech3300s.pdf |title=EBU middleware reports Tech 3300s |format=PDF |access-date= |accessdate=2010-08-19}}</ref>

==Types==

===Message-oriented middleware===

[[Message-oriented middleware]] (MOM) <ref>Curry, Edward. 2004. [http://www.mendeley.com/download/public/1652511/4338215212/cce0f06f047faa57879a1fc36a8e8d6d754d2f6a/dl.pdf "Message-Oriented Middleware"] {{deadDead link|date=JuneJanuary 20172019 |bot=InternetArchiveBot |fix-attempted=yes }}. In Middleware for Communications, ed. Qusay H Mahmoud, 1-28. Chichester, England: John Wiley and Sons. {{doi|10.1002/0470862084.ch1}}. {{ISBN|978-0-470-86206-3}}</ref> is middleware where transactions or event notifications are delivered between disparate systems or components by way of messages, often via an [[enterprise messaging system]]. With MOM, messages sent to the client are collected and stored until they are acted upon, while the client continues with other processing.

; Enterprise messaging system

: An [[enterprise messaging system]] is a type of middleware that facilitates message passing between disparate systems or components in standard formats, often using [[XML]], [[SOAP]] or [[web services]]. As part of an enterprise messaging system, [[message broker]] software may queue, duplicate, translate and deliver messages to disparate systems or components in a messaging system.

; Enterprise service bus

: [[Enterprise service bus]] (ESB) is defined by the [[Burton Group]] <ref name="ms-on-esb">{{Cite web|url=http://msdn.microsoft.com/en-us/library/aa475433(BTS.10).aspx|title=Microsoft on the Enterprise Service Bus (ESB)|date=August 2005|quote=The ESB label simply implies that a product is some type of integration middleware product that supports both MOM and Web services protocols.}}</ref> as "some type of integration middleware product that supports both [[message-oriented middleware]] and [[Web services]]".

===Intelligent middleware===

<ref>"[http://www.cougaarsoftware.com/files/CSI_ActiveEdge.pdf Choosing the Right Middleware] {{webarchiveWebarchive|url=https://web.archive.org/web/20120402121113/http://www.cougaarsoftware.com/files/CSI_ActiveEdge.pdf |date=2012-04-02 }}" </ref>

Intelligent [[Middleware]] (IMW) provides [[real-time intelligence]] and event management through [[intelligent agents]]. The IMW manages the [[real-time processing]] of high volume sensor signals and turns these signals into intelligent and actionable business information. The actionable information is then delivered in end-user power dashboards to individual users or is pushed to systems within or outside the enterprise. It is able to support various heterogeneous types of hardware and software and provides an API for interfacing with external systems. It should have a highly scalable, [[distributed architecture]] which embeds intelligence throughout the network to transform raw data systematically into actionable and relevant knowledge. It can also be packaged with tools to view and manage operations and build advanced network applications most effectively.

==={{Anchor|EMBEDDED}}Content-centric middleware===

Content-centric middleware offers a simple ''provider-consumer'' abstraction through which applications can issue requests for uniquely identified content, without worrying about where or how it is obtained. Juno is one example, which allows applications to generate content requests associated with high-level delivery requirements.<ref>[http://www.dcs.kcl.ac.uk/staff/tysong/files/PhD.pdf Juno] {{webarchiveWebarchive|url=https://web.archive.org/web/20110426045143/http://www.dcs.kcl.ac.uk/staff/tysong/files/PhD.pdf |date=2011-04-26 }} , Gareth Tyson, A Middleware Approach to Building Content-Centric Applications. PhD Thesis, Lancaster University (2010).</ref> The middleware then adapts the underlying delivery to access the content from sources that are best suited to matching the requirements. This is therefore similar to [[Publish/subscribe]] middleware, as well as the [[Content-centric networking]] paradigm.

; Remote procedure calcall

: [[Remote procedure call]] middleware enables a client to use services running on remote systems. The process can be [[Synchronization (computer science)|synchronous]] or [[Asynchrony (computer programming)|asynchronous]].

; Object request broker

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; Embedded middleware

: Embedded middleware provides communication services and software/[[firmware]] integration interface that operates between embedded applications, the embedded operating system, and external applications.

===Policy Appliances===

Policy appliance is a generic term referring to any form of middleware that manages policy rules. They can mediate between data owners or producers, data aggregators, and data users. Among heterogeneous institutional systems or networks they may be used to enforce, reconcile, and monitor agreed information management policies and laws across systems (or between jurisdictions) with divergent information policies or needs. Policy appliances can interact with smart data (data that carries with it contextual relevant terms for its own use), [[intelligent agent]]s (queries that are self-credentialed, authenticating, or contextually adaptive), or [[context awareness|context-aware]] applications to control information flows, protect security and confidentiality, and maintain privacy. Policy appliances support policy-based information management processes by enabling rules-based processing, selective disclosure, and accountability and oversight.<ref>{{Citation |title=Designing Technical Systems to Support Policy: Enterprise Architecture, Policy Appliances, and Civil Liberties |date=2010 |work=Emergent Information Technologies and Enabling Policies for Counter-Terrorism |url=https://doi.org/10.1109/9780470874103.ch22 |access-date=2025-04-28 |publisher=IEEE |isbn=978-0-470-87410-3}}</ref>

Examples of policy appliance technologies for rules-based processing include analytic filters, [[Contextual searching|contextual search]], semantic programs, labeling and wrapper tools, and [[Digital rights management|DRM]], among others; policy appliance technologies for selective disclosure include anonymization, content personalization, subscription and publishing tools, among others; and, policy appliance technologies for accountability and oversight include [[authentication]], authorization, immutable and non-repudiable logging, and audit tools, among others.

===Other===

Other sources{{Citation needed|date=September 2010}} include these additional classifications:

*[[Transaction Processing System|Transaction processing monitors]]{{snd}} provides tools and an environment to develop and [[Software deployment|deploy]] [[distributed application]]s.<ref>{{Cite book|title=Performance-Oriented Application Development for Distributed Architectures: Perspectives for Commercial and Scientific Environments|last=Gerndt|first=Michael|publisher=IOS PR, Inc.|year=2002|isbn=1586032674|___location=|pages=978-1586032678}}</ref>{{Citation needed|date=September 2010}}

*[[Application server]]s{{snd}} software installed on a computer to facilitate the serving (running) of other applications.<ref>{{Cite book|title=Network Dictionary|last=Dong|first=Jielin|publisher=Javvin Press|year=2007|isbn=1602670005|___location=|pages=978-1602670006}}</ref>{{Citation needed|date=September 2010}}

==Integration Levels==

===Data Integration===

*Integration of data resources like files and databases

===Cloud Integration===

*Integration between various cloud services

===B2B Integration===

*Integration of data resources and partner interfaces

===Application Integration===

*Integration of applications managed by a company

==Vendors==

[[IBM]], [[Red Hat]], [[Oracle Corporation]] and [[Microsoft]] are some of the vendors that provide middleware software. Vendors such as [[Axway]], [[SAP AG|SAP]], [[TIBCO]], [[Informatica]], [[Objective Interface Systems]], [[Pervasive Software|Pervasive]], ScaleOut Software and [[webMethods]] were specifically founded to provide more niche middleware solutions. Groups such as the [[Apache Software Foundation]], [[Opensaf|OpenSAF]], the [[ObjectWeb|ObjectWeb Consortium]] (now OW2) and OASIS' [[AMQP]] encourage the development of [[Open-source software|open source]] middleware. Microsoft .NET "Framework" architecture is essentially "Middleware" with typical middleware functions distributed between the various products, with most inter-computer interaction by industry standards, open APIs or RAND software licence. [[Solace Corporation|Solace]] provides middleware in purpose-built hardware for implementations that may experience scale. [[StormMQ]] provides [[Message Oriented Middleware]] as a service.

==See also==

{{Portal|Information technology}}

* [[Comparison of business integration software]]

* [[Middleware Analysts]]

* [[Service-oriented architecture]]

* [[Enterprise Service Bus]]

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==External links==

{{Wiktionary}}

*[http://middleware.internet2.edu/ Internet2 Middleware Initiative] {{Webarchive|url=https://web.archive.org/web/20050723082700/http://middleware.internet2.edu/ |date=2005-07-23 }}

*[http://www.swami.se/ SWAMI - Swedish Alliance for Middleware Infrastructure]

*[https://web.archive.org/web/20040220065312/http://www.omii.ac.uk/ Open Middleware Infrastructure Institute (OMII-UK)]

*[https://web.archive.org/web/20191213122020/https://www.srinsofttech.com/what-are-the-levels-in-the-middleware-integration.html Middleware Integration Levels]

*[http://tech.ebu.ch/docs/tech/tech3300.pdf European Broadcasting Union ([[EBU]]) Middleware report].

*[http://tech.ebu.ch/docs/tech/tech3300s.pdf More detailed supplement to the European Broadcasting Union Middleware report].

*[http://www.ow2.org/ ObjectWeb - international community developing open-source middleware]

{{Authority control}}

[[Category:Middleware| ]]