Introduction to the Internet and the World Wide Web

Introduction

This tutorial gives a brief but hopefully enlightening introduction to the Internet. We discuss what it actually is, where it came from and, most importantly, what you can do with it. At the end there are a number of useful and interesting Web sites for you to browse through, and a quiz to test your browsing skills.

What is the Internet?

The internet is a computer's equivalent to the telephone system. It comprises two basic parts:

Lots of computers

Lots of wires connecting them together.

Like the telephone system there are also lots of exchanges; computers dedicated to routing messages to the right computer; these are largely invisible to the computer users.

The main point about the Internet is that it's very messy. There are wires everywhere, built by different people at different times, and they're all connected together in lots of different places.

The Internet provides a way for computers all over the world to `talk' to each other. Of course, computers talk a different language to humans - they talk in numbers, but it's still talking. The important thing is that they all talk the same language. Most computers talk a language called TCP-IP these days; those that don't need to have a translator!

Figure: How we talk

In some ways, the Internet is like the postal system, because messages are sent in packets. Each packet must have the address of the receiving computer, the address of the sending computer (so the receiving computer knows who to reply to), and then the message being sent. Like the postal system, packets can get delayed at busy times, and even lost!

And in other ways, the Internet is like the road system. Computers are interconnected in many different ways, with some major trunk routes which take heavy traffic, and some windy country lanes which serve only a few people. Some areas are well-planned out, like Milton Keynes, and some are a bit of a nightmare (I'm thinking of the M25); however, to my knowledge, there are no one-way roads in the Internet. The point is that if there are `roadworks' on one route, or if a town is closed all day for a street carnival, messages can easily be re-routed another way, although there is likely to be a short delay. There's no AA on the Internet though, so let's hope your computer messages never need towing away.

In a short while, we'll discover just what computers talk about, but first let's have a quick look at how the Internet was born.

Where did the Internet come from?

This is a very short history lesson; it's interesting because in order to understand how the Internet ended up as it did today, you need to look at when it was born and how it grew.

It all started in America. In the sixties, the US Government were very worried about being blown to smithereens by nuclear attack from the Russians. In those days there were only a few, very big, computers (they used to fill whole rooms), and a well-placed strike could wipe out the whole US military strategy computer system. They decided to build a `decentralized' computer system - several slightly smaller computers all connected together, so that if any one machine was trashed, the others would still be OK and the system as a whole would still function. It also meant that they could play Network DOOM!

And that's how it started. More and more computers were connected to this initial network (called ARPANET) and things grew. Initially, only the military had access, but later anyone was allowed to connect on at any point. Other networks were developing at the same time in other countries and when these joined on, the size of what was by then know as the Internet shot up. The bigger the Internet gets, the faster it grows. In 1969 there were four computers connected. Twenty years later, in 1989, there were 160,000. Last July there were 6.5 million and in the last six months this figure has increased to 9.5 million. At this rate, every man, woman and child in the world will have their own personal connection in about 10 years time!

Figure: Internet hosts

What does the Internet do?

The Internet itself doesn't really do anything exciting in itself; it just transmits sequences of numbers from computer to computer across the world. It's what you do with it that counts.

Here's a list of the main things people do with the Internet:

Personal communication

E-mail is an electronic version of the postal service. Type a message on your screen, enter the address of a friend, hit the `send' button and away it goes. The message is zapped across the world to its destination and placed in the recipient's electronic mailbox. Unlike the postal service (known as snail-mail to computer users), e-mails arrive in minutes, if not seconds. Luckily, junk e-mail has not yet hit the Internet.

When a more interactive form of communication is needed, you can hold an interactive `talk' session with someone. The screen splits in two. What you type appears in the top half and what the other person types appears in the bottom half. It's not as easy as using a telephone, but it's certainly a lot cheaper.

Remote working

This was the original intended use of the Internet. So long as you have a suitable password, you can `log in' to any machine on the Internet and use all its facilities. You might want to use a Cray MkII supercomputer to do some number crunching for you, or you may be working as part of a team spread all over the country (or world). Many people in the computer industry now work from home in this way.

Newsgroups (USENET)

Unbeknown to the general public, (USENET) is a collection of over 3000 discussion groups (newsgroups) where people worldwide exchange information, hold debates and generally gossip. Each newsgroup is dedicated to a particular topic, with names like com.amiga.games or rec.music.blur. Anyone can `post' a message on any newsgroup, airing their opinion on a subject or offering an answer to a question asked in an earlier posting. And everyone who reads that newsgroup will read what you write.

One of the biggest problems with newsgroups is `flaming' - people's opinions differ and when controversial viewpoints are posted, they inevitably start a flame war; this is essentially a slanging match between two or more people which gets very tedious for everyone else, but can sometimes be great fun to watch!

Getting information

This is fast becoming the predominant use of the Internet, and it's in this context that the Internet is referred to as the World Wide Web (or Cyberspace, or the Information Superhighway); people have gone Web-crazy; downloading text, pictures, computer programs and now even virtual reality scenes from all over the world.

It works like this. Everyone who is connected to the Internet sets aside an area of their system for outside access. In this area they place information (in computer files) that they want to be available on the Web. To access all this stuff all you need is a browser on your own machine, and a list of useful addresses. You type the address into your browser; it sends a message to the remote machine, requesting the file to be sent to you. Depending on the type of file, you can then read it, look at it, play it (it might be a game) or whatever.

Most files these days are HTML files; this is what you view when you use Mosaic or Netscape. HTML stands for HyperText Markup Language; the important bit is the `hypertext'. Hypertext is like normal text except that it usually looks more exciting (with nice fonts, icons and graphics) and, more importantly, it contains links to other related hypertexts. When you read one Web `page' there are usually at least ten links to follow. These might point to Web pages at different sites, in other countries even.

And because everyone everywhere is adding new Web pages every minute of every day, the amount of stuff out there is immense, and it keeps growing and growing. Any topic, any subject - news, share prices, the weather forecast, music, sports and so on and so on - you name it, somebody's written it. It's all too easy to spend hours and hours just `surfing' the Web, following links to new places, following more links and so on. The number of times you think, "I'll just follow one more, and then I'm stopping..."

A World Wide Web Quiz

Here's where you get to test your Web-browsing skills. Below is a list of questions, the answers to which can be found somewhere on the Web. You'll find some links to useful Web pages in the `links' section of the Summer School Web page. For some of the answers you may need to use a search engine; ask the helpers for more details.

To attempt the quiz, open another browser window so you don't have to keep returning here and then go surfing for the answers. Fill them in as you find them on the form below, then when you have them all, fill in your name and hit the `submit' button to send the answers to us.

Have fun!

1) What's on BBC1 tonight at 7.30pm?

2) Will it rain in Leeds tomorrow?

3) What's at number 37 in the singles chart this week?

4) How much is a bottle of Chilean Chardonnay wine?

5) What was the number of the National Lottery bonus ball this week?

6) What's the name of the road that goes round Holyrood Park in Edinburgh?

7) Who's at the top of the Premier Football League?

8) What's the headline in the Telegraph today?

9) What film is showing at the Rex cinema in Elland this week?

10) What's the phone number of a plumber in the LS12 area?

11) What's the top speed of a BMW 518i?