Web Technology note:- Web Server Concept:

Web Server Concept:

What is a web server?

A Web server is a software program which serves web pages to web users (browsers).
A web server delivers requested web pages to users who enter the URL in a web browser. Every computer on the Internet that contains a web site must have a web server program.
The computer in which a web server program runs is also usually called a "web server". So, the term "web server" is used to represent both the server program and the computer in which the server program runs.

Characteristics of web servers

A web server computer is just like any other computer. The basic characteristics of web servers are:

- It is always connected to the internet so that clients can access the web pages hosted by the web server.
- It has an application called 'web server' running always.

In short, a 'web server' is a computer or  a machine which is connected to the internet/intranet and has a software called 'web server'. The web server program will be always running in the computer. When any user tries to access a website hosted by the web server, it is actually the web server program which delivers the web page which client asks for.

All web sites in the internet are hosted in some web servers sitting in different parts of the world.

Where is my web server ?

When you try to access a web site, you don't really need to know where the web server is located. The web server may be located in another city or country, but all you need to do is, type the URL of the web site you want to access in a web browser. The web browser will send this information to the internet and find the web server. Once the web server is located, it will request the specific web page from the webserver program running in the server. Web server program will process your request and send the resulting web page to your browser. It is the responsibility of your browser to format and display the webpage to you.

How many web servers are needed for a web site?

Typically, there is only one web server required for a web site. But large web sites like Yahoo, Google, and MSN etc will have millions of visitors every minute. One computer cannot process such huge numbers of requests. So, they will have hundreds of servers deployed in different parts of the world so that can provide a faster response.

How many websites can be hosted in one server?

A web server can host hundreds of web sites. Most of the small web sites in the internet are hosted on shared web servers. There are several web hosting companies who offer shared web hosting. If you buy a shared web hosting from a web hosting company, they will host your web site in their web server along with several other web sites for a Fee.

Example of web server application:

1.       IIS

2.       2. Apache

What is a browser?

• Browser is an application, which helps us to view the Web sites and the web content.
• Web sites are located in some remote systems, which needs a special kind of program or an application to access them, such an application is called browser.
• A browser is an application which you can use to retrieve web pages from web sites and view.
• When you type a URL in the browser, the browser will convert it into a web request which web server can understand. Browser will send the request to web server using the HTTP protocol.
• When a web server returns a web page as a Response, the browser will understand the response and display the body of the response to the user in browser.
• In simple terms a browser can be defined as "A software application used to locate and display Web pages"
• You can create your own simple browser application using C++, C#, VB.NET or any other language you like. All you need to know is, how to compose a request which web server can understand, how to parse and display the response from web server and communicate with webserver using HTTP protocol.
• Even though the basic job of browser is just send requests to web server and receive response from the server, modern browser provide several other enhanced features including Back/Forward buttons, save viewed files to disk so that they can be viewed later, cache images so that the same images need not be downloaded again and again etc.
• Internet Explorer, Netspace, Mozilla is some of the popular web browsers currently available in the market.
• Netscape was the most popular web browser till 4-5 years back, but currently more than 90% of the internet users use "Internet Explorer" to browse the websites.