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In the 1960s, researchers began
experimenting with linking computers to each other and to people through telephone
hook-ups, using funds from the US Defense Department's Advanced Research Projects Agency
(ARPA).
ARPA wanted to see if computers in different locations could be linked using a
new technology known as packet switching. This technology, in which data meant for another
location is broken up into little pieces, each with its own "forwarding address"
had the promise of letting several users share just one communications line. Just as
important, from ARPA's viewpoint, was that this allowed for creation of networks that
could automatically route data around downed circuits or computers.
ARPA's goal was not the creation of today's international computer-using
community, but development of a data network that could survive a nuclear attack. Previous
computer networking efforts had required a line between each computer on the network, sort
of like a one-track train route. The packet system allowed for creation of a data highway,
in which large numbers of vehicles could essentially share the same lane. Each packet was
given the computer equivalent of a map and a time stamp, so that it could be sent to the
right destination, where it would then be reassembled into a message the computer or a
human could use.
As this system, known as ARPANet, grew, some enterprising college students (and
one in high school) developed a way to use it to conduct online conferences. These started
as science-oriented discussions, but they soon branched out into virtually every other
field, as people recognised the power of being able to "talk" to hundreds, or
even thousands, of people around the country.
In the 1970s, ARPA helped support the development of rules, or protocols, for
transferring data between different types of computer networks. These "Internet"
(from "internetworking") protocols made it possible to develop the
world-wide Net we have today that links all sorts of computers across national boundaries.
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By the close of the 1970s, links developed between
ARPANet and counterparts in other countries. The world was now tied together in a computer
web. In the 1980s, this network of networks, which became known
collectively as the Internet, expanded at a phenomenal rate. Hundreds, then thousands, of
colleges, research companies and government agencies began to connect their computers to
this world-wide Net. Some enterprising hobbyists and companies unwilling to pay the high
costs of Internet access (or unable to meet stringent government regulations for access)
learned how to link their own systems to the Internet, even if "only" for e-mail
and conferences. Some of these systems began offering access to the public. Now anybody
with a computer and modem, persistence and a small amount of money and persistence --
could tap into the world.
In the 1990s, the Net continues to grow at exponential rates. Some estimates are
that the volume of messages transferred through the Net grows 20 percent a month. In
response, government and other users have tried in recent years to expand the Net itself.
Once, the main Net "backbone" in the US moved data at 56,000 bits per second.
That proved too slow for the ever increasing amounts of data being sent over it, and in
recent years the maximum speed was increased to 1.5 million and then 45 million bits per
second. Even before the Net was able to reach that latter speed, however, Net experts were
already figuring out ways to pump data at speeds of up to 2 billion bits per second --
fast enough to send the entire Encyclopaedia Britannica across the country in just one or
two seconds. Another major change has been the development of commercial services that
provide internetworking services at speeds comparable to those of the government system.
In fact, what started as a government experiment is now largely a private enterprise. |