The three standards

The Web is made up of three standards: The Uniform Resource Locator (URL), which specifies how each page of information is given a unique "address" at which it can be found; Hyper Text Transfer Protocol (HTTP), which specifies how the browser and server send the information to each other, and Hyper Text Markup Language (HTML), a method of encoding the information so it can be displayed on a variety of devices. Berners-Lee now heads the World Wide Web Consortium, which develops and maintains these standards and others that enable computers on the Web to effectively store and communicate all kinds of information.

Pronunciation of "www"

Most English-speaking people pronounce the 9-syllable letter sequence www used in some domain names for websites as "double U, double U, double U", but many shorter pronunciations can be heard: "triple double U", "double U, double U" (omitting one W), "dub, dub, dub", "hex u", etc. Some languages do not have the letter w in their alphabet (for example, Italian), which leads to some people pronouncing www as "vou, vou, vou." Perhaps a shorter pronunciation will become standard usage in the future.

Depending on how the domain and web server is set up, a www website can often be accessed without mentioning the "www.", as long as the ".com" or other appropriate top-level domain is appended. Even this is not always necessary as some browsers will automatically try adding "www." and ".com" to typed URIs if a web page isn't found without them.

30. “Web server”

The term web server can mean one of two things:

1. a computer responsible for serving web pages, mostly HTML documents, via the HTTP protocol to clients, mostly web browsers;

2. a software program that is working as a daemon serving web documents.

Every web server (sense 1) is running a web server program (sense 2).

The most common web or HTTP server programs are:

• Apache HTTP Server from the Apache Software Foundation

• Internet Information Services (IIS) from Microsoft

• Zeus Web Server from Zeus Technology (http://www.zeus.com/)

• Sun ONE from Sun Microsystems (formerly Netscape's iPlanet nee Enterprise)

• Xerver a free open source GNU GPL web server

The most commonly-used web server program, Apache, with over 67% of market share as of October 2004, is available from the Apache Software Foundation.

Common features

Although web server programs differ in detail, they all share some basic common features. Every web server program operates by accepting HTTP requests from the network, and providing an HTTP response to the requester. The HTTP response typically consists of an HTML document, but can also be a raw text file, an image, or some other type of document.

Usually these documents are stored on the web server's local file system. Both URLs and local filenames have a hierarchical structure, and the server maps the URL onto the local file system in a simple way. When web server software is installed and configured, the server administrator specifies a local pathname as the root from which the server software should locate files. For example, suppose we are configuring server software to provide HTTP service on a server whose domain name is example.funnycorp.com. We might set the server software's root directory to /home/public/web/. Then, if a web user enters the URL http://example.funnycorp.com/lips/raspberry.html, the web server software running on the host example.funnycorp.com will retrieve the requested content from the file /home/public/web/lips/raspberry.html

Server

In computing, a server is:

• A computer software application that carries out some task on behalf of users. This is usually divided into file serving, allowing users to store and access files on a common computer; and application serving, where the software runs a computer program to carry out some task for the users. This is the original meaning of the term. Web, mail, and database servers are what most people access when using the internet.

• The term is now also used to mean the physical computer on which the software runs. Originally server software would be located on a mainframe computer or minicomputer. These have largely been replaced by computers built using a more robust version of the microprocessor technology than is used in personal computers, and the term "server" was adopted to describe microprocessor-based machines designed for this purpose. In a general sense, server machines have high-capacity (and sometimes redundant) power supplies, a motherboard built for durability in 24x7 operations, large quantities of ECC RAM, and fast I/O subsystem employing technologies such as SCSI, RAID, and PCI-X or PCI-Express.

Usage

Sometimes this dual usage can lead to confusion, for example in the case of a web server. This term could refer to the machine which stores and operates the websites, and it is used in this sense by companies offering commercial hosting facilities. Alternatively, web server could refer to the software, such as the Apache HTTP server, which runs on such a machine and manages the delivery of web page components in response to requests from web browser clients.