The Internet is a computer network covering the whole
world. We can use it to search through three billion pages of the WORLD WIDE WEB, or to keep in touch with people by EMAIL. Unlike
other networks, the Internet is not under anyone’s control. It is held
together by a set of standards, or rules, that set out how computers connected
to it should exchange information.
Table 7. HISTORY OF THE INTERNET
| 1963 | Arpanet created to link US research computers |
| 1970 | Packet switching first used |
| 1978 | TCP/IP protocols established for communication and data exchange |
| 1983 | TCP/IP made compulsory, effectively creating the Internet |
| 1990 | World Wide Web protocol created |
Data is sent across the Internet as small packets. Each packet
travels by the best route available, avoiding busy or broken links. Computers
linked to the Internet handle data using agreed protocols (procedures). The
most important are TCP (transfer control protocol) and IP (Internet
protocol).
People on the move or without their own computer can connect to the
Internet at an Internet café. They pay a small fee to use one of the
café’s machines. Public wireless points make it even easier to
get connected. A wireless-enabled computer can access the Internet through a
radio link in the café or another public place. You can also connect to
the Internet through a mobile phone.
CONNECTING TO THE INTERNET
Your computer does not connect directly to the Internet. Usually, it
connects through telephone wires to an Internet service provider (ISP). Your
computer is linked with one of theirs, which has a unique address on the
network. Anything you want to see goes to this address first, then to your
computer.
Email (short for electronic mail) is an electronic postal
service. It was invented in 1971, and works on any computer network but is now
mostly used on the Internet. A message starts from and ends up at a mail client
– the program used to write and read emails on a computer. In between,
it is handled by one or more mail transfer agents. These are computers that
pass the email on until it gets to the electronic mailbox specified by its
email address. An email is not private because it may pass through many
computers before it arrives, giving other people a chance to read it.
The World Wide Web is a collection of billions of files
held in a huge number of computers, all linked to the Internet. The files may
contain words, pictures, sounds, or almost anything else. They are linked to
each other by hypertext – a way of making a word or picture in one file
call up another file anywhere in the world.
Websites such as this are written in a computer language called
hypertext mark-up language (HTML). A computer program called a web browser
translates HTML into a neat layout of text and pictures on your screen. To see
a web page, you type its address into the address box. If you need to find
pages about a particular subject, you can use a search engine. Search engines
keep a constantly updated index of every word in billions of documents. They
produce a list of pages that might be suitable, and you click on any pages you
want to see.
A web address or URL (short for uniform resource locator) tells
the browser where to find a file and how to treat it. A slash (/) marks the
start of the file’s name. The “http” says the information
is to be handled as hypertext.
BIOGRAPHY: TIM BERNERS-LEE British, 1955- MARC ANDREESSEN American, 1971-
The World Wide Web owes its existence to British scientist Tim
Berners-Lee. He worked at a research lab called CERN in Switzerland. Frustrated
by the difficulty of working with information scattered all over the Internet,
he developed hypertext software to link it up. The result was the World Wide
Web, which came into public use in 1991. Marc Andreessen created the first
easy-to-use web browser in 1993.
