Cognitive Web server

In the opinion of many users, the success or failure of a Web website mainly lies in the content and functions provided by it. But the Web server that supports these content and functions is the real hero behind the scenes. According to statistics, there are more than 5 million websites around the world. A Web server is running behind each website. What is a Web server? How does it work ?......
From C/S to Web
The earliest network system was a simple host/Terminal System. All applications were completed by the host, and the terminal only ran the corresponding programs on the server. The arrival of the PC era has greatly improved computer networks and applications, there are fewer and fewer applications for terminal-oriented large hosts. In particular, the rise of network operating systems such as NetWare and Windows NT and the emergence of network database systems have opened up a new network application model-C/S (Client/Server-Client/Server) mode. The C/S mode is a two-layer system. The first layer is to process the logic and business logic on the client, and the second layer is the server systems such as databases running through the network. In the C/S mode, transactions are processed separately to achieve distributed computing of the network. Over a long period of time, it has also helped enterprises implement LAN construction, improved internal business management, and improved work efficiency. However, the C/S mode has obvious limitations in system integration and maintenance, operating interface consistency, and system scalability, therefore, just as the host/terminal network is replaced by a network system in the C/S mode, an updated system mode will also appear in the Internet/Intranet technology environment.
Internet/Intranet based on Web technology has been widely used in recent years. Intranet is an enterprise Intranet based on TCP/IP protocol and with Web as the core, with a low-cost, easy-to-use client browser, you can access your desired data on the enterprise's Web site anytime and anywhere. The consistency of the browser client operation interface avoids the diversity of client programs in the C/S mode. The open and standard connection solutions on the server allow enterprises to easily contact the outside world through the Internet. At the same time, the dynamic and interactive publishing of Web information has fundamentally changed the service quality of enterprises and increased their business opportunities.

Figure 1 Web Layer-3 structure
In the layer-3 Web technology, the database does not directly provide services to each client, but communicates with the Web server to achieve dynamic, real-time, and interactive customer information services. This function is implemented through server applications created by CGI, ISAPI, NSAPI, and Java. As shown in Figure 1.
What is Web Server)
The unique feature of Web technology is hyperlink and multimedia information. Web servers use HTML-HyperText Marked Language to describe network resources and create Web pages for Web browsers to read. HTML documents are characterized by interactivity. Both common text and graphics can be connected to other documents on the server through links in the document, so that customers can quickly search for the information they want. HTML web pages also provide forms for users to fill in and submit to the database through the server application. This type of database generally supports multimedia data.