The World Wide Web

David M. Marcovitz, Ph.D.

What Is the World Wide Web?

The World Wide Web (WWW) is a system for accessing information on the Internet. The Internet is a loosely affiliated interconnected network of computers all around the world. The WWW allows you to access information on some of those computers. Millions of computers are connected to the Internet, and tens of thousands of those computers have information that you can access.

There are two types of computers on the WWW: servers and clients. Servers are computers that provide information, and clients are computers that access the information. Servers run special software that makes the information placed on them available to the clients on the WWW. Clients run special software (called a browser) that can access the information made available on the server. The two most widely used browsers are Netscape Navigator and Internet Explorer.

World Wide Web Addresses

WWW servers all have names. When you want to access information on a server, you need to know the servers name. The name is divided into sections divided by periods. A period is pronounced dot, so the address www.loyola.edu would be pronounced: WWW dot LOYOLA dot E D U

Reading World Wide Web Addresses

To the uninitiated WWW addresses often look like a bunch of letters, dots, and slashes, with very little meaning. With a little guidance, they are not difficult to read. A WWW address is in the form of a Uniform Resource Locator (URL). A URL generally starts with the sequence:

http://

This tells the browser and server that this is a normal web page. Almost all addresses start with this, so if you see an address that leaves this off, don't worry about it. What does http stand for? I can never remember, and you would probably forget as soon as I told you.

The trick to reading WWW addresses is reading them from right to left in order to go from the most general to the most specific. Each part of the address (after the http://) is separated by a period (pronounced dot). So, the main Loyola web server is:

http://www.loyola.edu

This address has three parts: www, loyola, and edu.

Domain Names (The Far Right)

At the far right side of the address is the domain name. This tells you what kind of an institution owns the server. The following are the most common domain names:

EDU EDUcational Institution
COM Private COMpany
NET NETwork Provider
GOV GOVernmental Agency
ORG Nonprofit ORGanization
MIL MILitary Agency

In addition, some addresses from other countries (or from the United States) end in a country code. Here are some examples:

US United States
CA CAnada
UK United Kingdom
DE Germany (DEutschland)
IL IsraeL
ES Spain (ESpaña)

Finally, there are seven new domain names that have been approved in November 2000. These are not yet widely used, but they will be in the near future. They are:

AERO Air Transport Insdustry
BIZ Businesses
COOP Non-profit Cooperatives
INFO Information Services
MUSEUM Museums
NAME Personal Web Sites
PRO Professionsal Services (doctors, lawyers, etc.)

With this information, you can look at the far right side of a WWW address and know what kind of institution owns the server. That doesn't necessarily tell you too much about the information you will find at that server, but sometimes it is a clue. Additionally, some of the addresses are open to anyone while others are really restricted to those who fit the category. For example, anyone can purchase a .ORG domain, regardless of whether or not they are a non-profit organization, but only government agencies can get a .GOV domain.

The trickiest situation is when an address ends in COM. In this case, the address could be for a private company, but the information on that machine could be from individuals, organizations, or schools that pay a fee to rent space on that machine.

Subdomains (Moving to the Left)

The next part of an email address is the subdomain. This is more specific than the domain, and it usually tells you the specific company or organization that provided that owns the address. For example,

www.cso.uiuc.edu

has EDU as the domain, so we know it is an educational institution. Next is UIUC, which stands for University of Illinois at Urbana Champaign. So, we know that the address is an educational institution, and the specific institution is the University of Illinois at Urbana Champaign. In the following address,

www.cup.hp.com

we can see by COM that this is a private company, and HP tells us that the company is Hewlett Packard. Sometimes you will recognize the company or organization and sometimes you won't.

Sometimes that is all. Many address simply have a domain and a subdomain. This could be because the company is small and only has one computer, or it could be because the company has a central server that has links to other servers within the company.

What If There Is More (Moving Further to the Left)

If there are more than two parts to the machine name, then the next part will be more specific. This might be an organization or group within the company. It might be a specific facility within the company. It might be something you can't figure out. But in almost all cases, it is more specific.

For example,

www.cso.uiuc.edu

EDU tells us that this is an educational institution. UIUC tells us that this is at the University of Illinois at Urbana Champaign. CSO tells us that this is the Computing Services Organization (the organization at UIUC that provides most computing facilities).

www.cup.hp.com

COM tells us that this is an private company. HP tells us that this is Hewlett Packard. CUP tells us that this is the Cupertino facility at Hewlett Packard.

If we move all the way to the left, the last part might be the actual machine name. In many, but not all, WWW addresses, the first part is WWW.

Some addresses will have fewer parts (but always at least two for domain and subdomain), and others will have more. When I taught high school, our server had the following address:

www.phs.osceola.k12.fl.us

This address uses country domains (as do many K-12 schools). US tells us that it is in the United States. FL tells us that it is in Florida. K12 tells us that it is a K-12 school. Osceola tells us that it is in Osceola County. PHS tells us that it is at Poinciana High School. WWW tells us that the server is named WWW. Every step from left to right gets a little more specific and gives a little more information.

What About Those Slashes?

If you use a WWW address like the ones above, you will get to the main page on the server. In many cases, that is exactly where you want to go because the information you are seeking will be there, or that main page will have pointers to the other pages that you want to access. Many times, however, you will have an address that has more parts than the ones above. For example:

www.loyola.edu/education/facstaff/marcovitz/interesting.html

In this case, the parts after the server's address are directories and subdirectories on the server. www.loyola.edu tells us that the computer is (from right to left) at an educational institution, the institution is Loyola College, and it is called www. The rest of the address is separated by forward slashes. education is a directory on that computer for the Education Department; facstaff is for Education Department faculty and staff; marcovitz is Dr. Marcovitz's directory (Dr. Marcovitz is a faculty/staff member in the Education Department), and interesting.html is a specific file within that directory.

Capitalization

For the first part of the address, capitalization does not matter. WWW.LOYOLA.EDU, www.loyola.edu, and WwW.LoYoLa.EdU will all be interpreted the same way. However, capitalization after the slash matters on many machines (this depends on the server). If you are given a WWW address, it is best to use the capitalization exactly as it is given to you (at least for the part after the slashes).

Conclusion

You can not usually tell everything about a WWW address by looking at it. Some addresses are confusing and use initials that you won't recognize. However, by breaking it down into parts, it should not look to you like a jumble of random symbols, numbers, and letters.


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This page was prepared by Dr. David M. Marcovitz.

Last Updated: February 14, 2003