An initial discussion of XML, Web services, and. NET Frameworks

Application development technology is taking a qualitative leap, radically increasing the productivity of developers, and it opens the door to an application that leads to new concepts.
In the past, developers have been building applications by integrating local system services. In this mode, developers have access to rich development resources and can strictly control the behavior of the application.
Today, developers have largely freed themselves from this pattern and are committed to building N-tier systems with complex structures that integrate numerous applications throughout the network and greatly enhance the value of the application. This allows developers to focus on discovering the unique business value of the software without having to worry about how to build the infrastructure day and night. The joyful situation will come into being: the time that the software puts on the market is shortened greatly, the programmer's programming efficiency is obviously improved, the most fundamental is to develop the quality software.
We are entering a new computing age, the core technology of an internet age is "Extensible Markup Language", XML. XML creates powerful applications that anyone can access and use from anywhere. It greatly expands the function of the application and realizes the uninterrupted transmission of the software. In this large environment, software is not exactly the program that was installed from the CD, but it has evolved into a service that is similar to the caller's ID verification or pay-per-view television, where people can book such services through the communication media.
All this is achieved by combining tightly coupled, highly efficient n-tier computing with a message-oriented, loosely coupled web concept. We refer to this computational style as a Web service, which marks the beginning of a new era in the application development technology of mankind. A Web service is an application that uses standard Internet protocols, such as Hypertext Transfer Protocol (HTTP) and XML, to be functionally programmatic in the Internet and intranet. The Web service can be treated as a component programming on the Web.
In theory, developers can integrate Web services into an application by invoking the Web application Programming Interface (API), just as they would invoke a local service, unlike web API calls that can be sent over the Internet to a service located on a remote system. For example, Microsoft Passport Services enable developers to authenticate an application. Through the Passport Services program, developers can take advantage of the basic structure of the passport to maintain a user database by running Passport to ensure its normal operation, regular backups, and so on.
Loosely coupled distribution of application logic across a network is not an entirely new concept, and the distribution and integration of application logic across the Web is a new concept.
In the past, distributed application logic required the use of distributed object models such as: Microsoft's Distributed Component Object Model (DCOM), the object Management group's Common Object Request Agent architecture (CORBA), or the Sun's Remote method call (RMI). By using this basic structure, developers can still have the rich resources and accuracy to use the local model, and can place services on remote systems.