Английский для бакалавров. Зарубина Л.П - 66 стр.

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66
signed to survive a nuclear war. Information sent over the Internet takes the shortest
path available from one computer to another. Because of this, any two computers on
the Internet will be able to stay in touch with each other as long as there is a single
route between them. This technology is called packet switching. Owing to this tech-
nology, if some computers on the network are knocked out (by a nuclear explosion,
for example), information will just route around them. One such packet-switching
network already survived a war. It was the Iraqi computer network, which was not
knocked out during the Gulf War.
Most of the Internet host computers (more than 50%) are in
the United States, while the rest are located in more than 100
other countries. Although the number of host computers can be
counted fairly accurately, nobody knows exactly how many
people use the Internet; there are millions, their number growing
by thousands each month worldwide.
The most popular Internet service is e-mail. Most of the people, having access to
the Internet, use the network only for sending and receiving e-mail messages. How-
ever, other popular services are available on the Internet: reading USENET News, us-
ing the World-Wide Web, telnet, FTP, and Gopher.
In many developing countries the Internet may provide business people with a reli-
able alternative to the expensive and unreliable telecommunication systems of these
countries. Commercial users can communicate over the Internet with the rest of the
world and do it very cheaply. When they send e-mail messages, they only have to pay
for phone calls to their local service providers, not for calls across their countries or
around the world. But who actually pays for sending e-mail messages over the Inter-
net long distances, around the world? The answer is very simple: a user pays his/her
service provider a monthly or hourly fee. Part of this fee goes towards its costs to
connect to a larger service provider. And part of the fee got by the larger provider
goes to cover its cost of running a worldwide network of wires and wireless stations.
But saving money is only the first step. If people see that they can make money
from the Internet, commercial use of this network will drastically increase. For ex-
ample, some western architecture companies and garment centres already transmit
their basic designs and concepts over the Internet into China, where they are re-
worked and refined by skilled – but inexpensive – Chinese computer-aided-design
specialists.
However, some problems remain. The most important is security. When you
send an e-mail message to somebody, this message can travel through many different
networks and computers. The data is constantly being directed towards its destination
by special computers called routers. Because of this, it is possible to get into any of
computers along the route, intercept and even change the data being sent over the
Internet. In spite of the fact that there are many strong encoding programmes avail-
able, nearly all the information being sent over the Internet is transmitted without any
form of encoding, i.e. “in the clear”. But when it becomes necessary to send impor-
tant information over the network, these encoding programmes may be useful. Some
American banks and companies even conduct transactions over the Internet. How-

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