Internet

1 INTERNET

1.1 Whatґs the Internet?

That question is rather difficult to answer because the Internet is so many things to so many different people. It's simply a series of computer networks linked together all over the world, communicating almost all the time with one another.

A single network of computers, is for example, all the computers linked together within our school building. The Internet consists of thousands of these networks communicating together, like a big net or web! University networks connected to government networks connected to business networks connected to private networks - this is the Internet! These computer networks are physically linked together by telephone, radio, cable lines or via satellite. Networks from other continents are interconnected by the large, intercontinental telephone and fibre optic communication lines that run below the ocean floor.

1.2 Size of the Internet

Nobody knows for sure how big the Internet is. It is estimated that there are approximately thirty to thirty-eight million people that are ‘on-line,’ with sites on every continent. In fact, the Internet has grown at an exponential rate since its beginning.

It is the largest network of computers in the world and is growing at about ten percent per month. That means that at the current rate of growth, the Internet-users will double just ten months from today. If you believe current predictions, it will become true that by the year 2010 everyone of the western countries will be connected to the Internet.

1.3 History and Property

The Internet began as ARPANET (Advanced Research Projects Agency - Network), a US military network in the 1960s. The United States military needed a system for its researchers to communicate and share programs with one another over long distances. In other parts of the world, similar networks developed.

Over time, all these separate networks have linked together using a common communication protocol called TCP/IP. Businesses and private individuals then started connecting and eventually the network became known as the Internet. Today, no individual, no corporation and no government owns the Internet - it is owned, operated and maintained by all those who use it.

1.4 Services

1.4.1 E-Mail

Perhaps the first step that many people have tried when using the Internet is E-mail. E-Mail is a method of sending text and pictures to other people on the net. It is an electronic message from a sender to a recipient, (or multiple recipients.) Some people say that an email message is the Internet equivalent of sending a fax. Compared to postal E-mail, (often called ‘snail-mail’ by Internet users), E-mail is probably much faster. But there are several problems with E-mail.

In theory, messages can be sent back and forth immediately (usually within a few seconds), regardless of whether the message is sent to the next building or to the next continent. Nevertheless E-mail messages may sit in the recipient’s electronic mailbox for days or weeks until the user checks them. To be able to send an E-mail message, you must know the E-mail address of the person you want to send the message to.

A person's E-mail address is constructed from the username they use to login to their provider and the computer's Internet host name. By combining the two with an @ sign between, them you have created that user's E-mail address.

1.4.2 World Wide Web

I think it’s advantageous to start with the widely know service named WWW (which means World Wide Web). The World Wide Web makes up a very large percentage of the Internet. Nearly seventy percent of all information searches are handled through the World Wide Web. Information is quickly found in the World Wide Web through typing in key words. The key words are searched through different search engines, such as Infoseek and Lycos, or through search directories, such as Yahoo and Magellan. These search engines look for key words in their databases. The search results from the search engine are then listed and the user can choose from the titles found.

The WWW is a system for publishing text and pictures on the net so they can be accessed at any time by everybody who is interested in. You can compare the WWW with a library without walls, that is open 24 hours