The Internet is composed of many interconnected computer
networks. Each network may links tens, hundreads, or even thousand of
computers, enabling them to share information with one another and to share
computional resources such as powerful supercomputer and data bases of
information. The has made possible for people all over the world to communicate
with one another effectively and inexpensively. Unlike traditional broadcasting
media, such as radio and television, the Internet does not have a centralized distribution
system. Instead, an individual who has Internet access can communicate directly
with anyone else on the Internet, make information available to others, find
information provided by others, or sell products with a minimum overhead cost.
The Internet has brought new opportunities to government,
business, and education. Governments use the
Internet for internal communication, distribution of information, and
automated tax processing. In addition to offering goods and services online to
customers, businesses use the Internet to interact with other businesses. Many
individuals use the Internet for communicating through eletronic mail (e-mail),
for news and research information, shopping, paying bills, online banking.
Educational institutions use the Internet for research and to deliver courses
material to students.
Use of the Internet has grown termendously since its
inception. The Internet's success arises from its flexibility. Instead of
restricting component networks to a particular manufacturer or particular type,
Internet technology allows interconnection of any kind of computr network No
network is too large or too small, too ast or too slow to be interconnected.
Thus, the Internet includes inexpensive networks that can only connect a few computers
within a single room as well as expensive networks that can span a continent
and connect thousands of computers.
Internet service providers (ISPs) provide Internet access to
customers, usually for a monthly fee. A customers who subscribes to an ISP's
service uses the ISP's network to access the Internet. Because ISPs offer their
services to the general public, the networks they operate are known as public
access networks. In the United States, as in many countries ISPs are private
companies; in countries where telephone service is a government-regulated
monopoly, the government often controls ISPs.
An organization that has many computers usually owns and
operates a private network, called an inranet, which connects all the computers
within the organization. To provide Internet sevice, the organization. To
provide Internet service, the organizations connects its intranet to the
Internet. Unlike public access networks, intranet are restricted to provide
security. Only authorized computers at the organization can connect te the
intranet, and the organization restricts communication between the intranet and
the global Internet. The restrictions allow computers inside the organization
to exchange information but keep the information confidential end protected
from outsiders.
The Internet has doubled in size every 9 to 14 months since
it began in the late 1970s. In 1981 only 213 computers were connected to the
Internet. By 2000 the number had grown to more than 100 million. The current
number of people who use the Internet can only be estimated. One survey found
that there were 61 million Interner users worldwide at the end of 1996, 148
million at the end of 1998, and 407 million by the end of 2000. Today, the
number of Internet users is estimated to be more than 800 million worldwide!
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