Robert Kahn, who helped create the protocols used both on ARPANET and the Internet, attends the 10th Annual Webby Awards.

Scott Wintrow/Getty Images

The End of ARPANET

Between 1969 and 1977, ARPANET grew from a network of four computer sites to one with 111 computers belonging to universities, research facilities and the military. Using satellite links, ARPANET connected computer systems in the continental United States to computers in Hawaii and Europe. Even though the network had grown, few people actually had access to the system. In general, the public remained unaware of ARPANET's existence.

Other ARPANET networks began to go live, including USENET, Ethernet, CSNET and BITNET. The ARPANET Request for Comments 827 established an External Gateway Protocol that made it possible for separate networks to access each other, even though access to ARPANET was still restricted for official use. In 1983, the military section of ARPANET split off from the network; its only connection to the larger network was a few e-mail gateways. The military renamed its smaller network MILNET, which would later become part of the Department of Defense Data Network (DDN) [source: Living Internet].

In 1986, five supercomputer centers formed a network called NSFNET. Before long, NSFNET grew to include several universities in its network. Other networks began to consolidate into larger systems. People referred to this larger collection of networks and gateways as the Internet. While the era of the personal computer began in the late 1970s, the Internet still remained a resource for universities, corporations and the government.

ARPANET's infrastructure was beginning to show its age. The system's IMPs weren't as efficient or powerful as the computer nodes in other networks. Organizations on ARPANET began to transition to other networks, mainly NSFNET. In 1990, DARPA pulled the plug on the ARPANET project. The organization's goals had been met. The United States had a nationwide computer network that not only linked powerful resources together, but also could continue operating if a significant portion of the network stopped working. Even more impressive, this network now spanned the globe, connecting computers from one side of the world to the other.

To learn more about ARPANET and related topics, follow the links on the next page.

Hacking ARPANET

Hacking culture flourished within ARPANET. Most hackers worked to contribute improvements to the system, uploading useful programs, improving existing applications or creating a community where people could talk about programming. Hackers also invented jargon that would carry over into the Internet. Not all hacker activities had positive outcomes -- the distribution of a computer virus led a total system crash in 1980 [source: BBC News]. ARPANET was a big target for hackers like Kevin Poulsen, who was caught gaining unauthorized access to the network in 1983 using the nickname Dark Dante [source: Wired].