
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 the 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.
This system allowed computers to share data and the researchers to exchange electronic mail, or e-mail. In itself, e-mail was something of a revolution, offering the ability to send detailed letters at the speed of a phone call.
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 recognized 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 worldwide Net we have today that links all sorts of computers across national boundaries. 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 worldwide 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 -
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 upon a time the main Net
"backbone" in the U.S. 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 first to 1.5 million and then
to 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 Encyclopedia 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 mid-1994, the U.S. government removed
itself from any day-to-day control over the workings of the Net, as regional
and national providers continue to expand.
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