What are Web Servers?

Web Server Communication

Web servers are one of the endpoints in communication through the World Wide Web. According to its inventor, Tim Berner-Lee, the World Wide Web is “the universe of network-accessible information, an embodiment of human knowledge.” While the latter part of this definition is arguable, the former offers a starting point through which to understand the magnitude of the Web.

The World Wide Web is the global structure of electronically connected information. It refers to the global connections between computers that allow users to search for documents or web pages by requesting results from a web server. These documents are hyper-text based (written in HTML-Hypertext Markup Language), allowing users to travel to other pages and extend their research through links. They are delivered in a standardized protocol, HTTP (Hypertext Transfer Protocol, usually written in lower case letters), making HTML documents intelligible across hardware and software variations.

This information travels through web servers and web browsers. The communication initiates from a user request through a web browser. The request is delivered to a web server in ‘http’ format. The server then processes the request, which can be anything from a general search to a specific task, and returns the results in the same format. The results are written in HTML, which is the language web pages are written in that supports high-speed travel between web pages.

HTML is also essential for displaying many of the interactive features on web pages, such as linking web pages to other objects, like images. An important distinction when defining web servers is between hardware and software. A web server is also a computer program (software) that performs the functions outlined above. This article will provide a basic overview of web servers. It will begin with a brief history, and then define the terms and components of how web server communication works in more detail. The article will conclude with a description of common web server features.

Web Servers History

The World Wide Web was developed by Tim Berners-Lee for his employer CERN or the European Organization for Nuclear Research between 1989-1991. In 1990 he wrote the program for the World Wide Web. This program created the first web browser and HTML editor. It was the first program to use both FTP and HTTP.

FTP is “file transfer protocol” and is used to transfer data over a network. Protocol is the set of standards that defines and controls connection, communication, and the transfer of data between two computer endpoints. It determines the format and defines the terms of transmission.

As previously mentioned, HTTP is the protocol that supports hyper-text documents. Both of these protocols are necessary for communication over the Internet or World Wide Web. The source code for the World Wide Web was made public in 1993, making it available to everyone with a computer. The technology continued to develop and between 1991-1994 extended from communication only between scientific organizations, to universities and, finally, to industry. By 1994, computers could transfer data between each other through a cable linking ports across various operating systems (OSs). Operating systems manage a computer’s hardware and software systems.

The first web server, also written by Berners-Lee, ran on NeXTSTEP, the operating system for NeXT computers. The other technology authored by Berners-Lee that is required for Web communication is URLs (Universal Resource Locators). These are the uniform global identifiers for documents on the Web allowing for easily locating them on the Web. Berners-Lee is also responsible for writing the initial specifications for HTML. The first web server was installed in the United States on December 12, 1991 and at SLAC (Stanford Linear Accelerator Center), which is a U.S. Department of Energy laboratory.

In 1994, Berners-Lee created the World Wide Web Consortium (W3C) to regulate and standardize the various technologies required for Web construction and communication. It was created to insure compatibility between vendors or industry members by having them agree on certain core standards. This insures the ability for web pages to be intelligible between different operating systems and software packages. After 2000, the web exploded. As of March 2007, there exist 110 million web sites on the World Wide Web.