In the 1960s, researchers began experimenting with linking computers to each other and to people through telephone hook-ups, using funds from the U.S 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, which had the promise of letting several users share just one communication line. Previous computer networking efforts had required line between each computer on the network, sort of like a train track on which only one train can travel at a time. 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 ARPA Net, 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, protocols, for transferring data between different types of computer networks. These “Internet” protocols made it possoble4 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 ARPN Net 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 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 grows at exponential rates. Some estimates are that the volume of messages transferred through the Met grows 20 prevent 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 U.S moved data at 1.5 million bits per second. That proved too slow for 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 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 fact, by mid-1994, the U.S. government will remove itself from any day –to-day control over the working net, as region l and national providers continue to expand.
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