Messaging middleware and Getting started with WebSphere MQ

Message Queuing technology:

is a technique for exchanging information among distributed applications. Message Queuing can reside in memory or on disk, and queues store messages until they are read by the application. With Message Queuing, applications can execute independently-they do not need to know each other's location, or wait for the receiving program to receive this message before proceeding.

Message Middleware Overview:

In distributed computing environments, in order to integrate distributed applications, developers need to provide effective means of communication for distributed applications in heterogeneous network environments. In order to manage the information that needs to be shared, it is important to provide the public information exchange mechanism for the application.

the main methods for designing distributed applications are:

Remote Procedure Call (PRC)--one of the basic standard components of the Distributed computing Environment (DCE);

RPC is the component of DCE and is an application-integrated software standard released by the Open Software Foundation (OSF). RPC mimics a program that uses a function reference to refer to another program's traditional programming method, which is the form of a procedure call, and once invoked, the program's control turns to the called program.

When RPC is implemented, the called procedure can reside in another system, either locally or in a remote place, and is executed. When the called program finishes processing the input data, the result is placed in the return variable of the procedure call back to the calling program. After the RPC is complete, program control returns to the calling program immediately. So RPC mimics the call/return structure of the subroutine, which provides only the synchronous data exchange between the client (the calling program) and the server (called procedure).

Object Transaction Monitoring (OTM)--The combination of object-oriented industry standard and transaction processing (TP) monitoring technology based on CORBA;

The CORBA specification defines the architecture of using object-oriented techniques and methods, the common Client/server programming interface, the guidelines for transmitting and translating data between multiple platforms, the development of a Distributed Application Interface language (IDL), and the client/for the construction of the distribution. The server application provides a broad and consistent pattern.

Message Queuing (MessageQueue)--loosely coupled method for constructing distributed applications.

The messaging team is listed as a loosely coupled method for constructing distributed applications that are implemented synchronously or asynchronously. Message Queuing API calls are embedded in new or existing applications that provide information exchange by sending messages to memory or disk-based queues or reading them out. Message Queuing can be used in an app to perform a variety of functions, such as requiring services, exchanging information, or asynchronous processing.

Middleware is a kind of independent system software or service program, and distributed Application system uses this software to share resources among different technologies, manage computing resources and network communication. It is a key software in the computer system, it can realize the interconnection and interoperability of the application, and can ensure the safe, reliable and efficient operation of the system. The middleware is located between the user application and the operating system and the network software, it provides the common communication means for the application, and is independent of the network and the operating system. Middleware provides developers with an application interface for all environments, and when an application embeds its function calls, it can take advantage of the capabilities of the specific operating system and network environment it runs to perform communication functions for the application.

If there is no message middleware to complete the exchange of information, application developers in order to transfer data, it is necessary to learn how to use the network and operating system software functions, write the appropriate application to send and receive information, and exchange information there is no standard method, each application must be specific programming and multi-platform, Communication of one or more applications in different environments. For example, in order to achieve communication between different host systems on the network, it will require knowledge of how information is exchanged on the network (such as socket programming with TCP/IP), and in order to achieve communication between different processes within the same host, knowledge of the operating system's Message Queuing or named pipes (Pipes) will be required.

There are many types of middleware, such as transaction management middleware (such as IBM's CICS), Web application Server middleware for Java applications (such as IBM's WebSphere Application Server), and message transfer middleware (MOM). It simplifies the transmission of data between applications, shields the underlying heterogeneous operating systems and network platforms, provides consistent communication standards and application development, and ensures reliable, cross-platform information transfer and data exchange in a distributed computing network environment. It is based on the storage-forwarding mechanism of message queue, and provides the unique asynchronous transmission mechanism, which can realize application integration and data exchange based on message transmission and asynchronous transaction processing.

IBM message Middleware MQ is the most market-share messaging middleware product in the industry with its unique security mechanism, simple and fast programming style, excellent stability, scalability and cross-platform, as well as strong transaction processing and messaging capabilities.

MQ has a strong cross-platform, and it supports up to 35 platforms. It supports a variety of mainstream UNIX operating system platforms such as: HP-UX, AIX, SUN Solaris, Digital Unix, Open VMX, SUNOS, NCR Unix, support for various host platforms such as os/390, Mvs/esa, Vse/esa Windows NT Server is also supported. Support for Windows9x/windows nt/windows 2000 and Unix (UnixWare, Solaris) and major Linux versions (Redhat, Turbolinux, etc.) on PC platforms. In addition, MQ supports a variety of other operating system platforms such as: OS/2, as/400, Sequent Dynix, SCO OpenServer, SCO UnixWare, tandem, etc.