Middleware is a type of computer software that connects software components and applications. It includes a set of services. To facilitate the interaction between multiple software running on one or more machines through the network. The interoperability provided by this technology has promoted the evolution of consistent distributed architectures that are commonly used to support and simplify complex distributed applications, including web servers, transaction monitors, and message queuing software.
Middleware (middleware) is a major category of basic software and belongs to the category of reusable software. As the name suggests, middleware is between the operating system software and the user's application software.
Middleware is the lower layer of application software on top of the operating system, network and database. Its overall function is to provide an operating and development environment for the upper layer of application software to help users develop and integrate flexibly and efficiently. Complex application software. Among the many definitions of middleware, the most commonly accepted one is that expressed by IDC: middleware is an independent system software or service program, and distributed application software uses this software to share resources between different technologies. The software sits on top of the client server's operating system and manages computing resources and network communications.
IDCThe definition of middleware shows that middleware is a type of software, not a kind of software; middleware not only realizes interconnection, but also realizes interoperability between applications ;Middleware is software based on distributed processing, and its most prominent feature is its network communication function.
Middleware is a universal service located between the platform (hardware and operating system) and the application. As shown in Figure 1, these services have standard program interfaces and protocols. For different operating systems and hardware platforms, they can have multiple implementations that comply with interface and protocol specifications.
Figure 1 Conceptual model diagram of middleware
It may be difficult to give a strict definition of middleware, but middleware should have the following characteristics:
① Meet the needs of a large number of applications;
② Run on a variety of hardware and OS platforms;
③ Support distributed computing and provide transparency across networks, hardware and OS platforms Interaction of applications or services;
④Support standard protocols;
⑤Support standard interfaces.
Due to the importance of standard interfaces for portability and standard protocols for interoperability, middleware has become an important part of many standardization efforts. For application software development, middleware is far more important than operating systems and network services. The program interface provided by middleware defines a relatively stable high-level application environment. No matter how the underlying computer hardware and system software are updated, as long as the middleware is By upgrading and updating, and keeping the middleware's external interface definition unchanged, the application software requires almost no modifications, thereby protecting the company's significant investment in application software development and maintenance.
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