Proper noun
ARPANET
(military, networking) Initialism of Advanced Research Projects Agency Network (the world's first operational packet-switching network)
ARPAnet
Alternative spelling of ARPANET
After the ARPANET had been up and running for several years, ARPA looked for another agency to hand off the network to; ARPA's primary mission was funding cutting edge research and development, not running a communications utility. Source: Internet
ARPANET allowed different computers to be connected to allow e-mails to be relayed from computer to computer, with the first ARPANET e-mail being sent in 1971. citation Multics also pioneered instant messaging between computer users in the mid-1970s. Source: Internet
Although Kahn and Cerf started working on the Internet and TCP/IP in 1973, it wasn’t until January 1, 1983 that the ARPANET switched to TCP/IP (known as flag day). Source: Internet
Beginning with his work at Bolt Beranek and Newman (BBN), Kahn discusses his involvement as the ARPANET proposal was being written, his decision to become active in its implementation, and his role in the public demonstration of the ARPANET. Source: Internet
By the 1990s it provided a worldwide networking infrastructure. citation Unlike ARPANET, X.25 was commonly available for business use. Source: Internet
A sense of the difficulty in documenting early developments that led to the internet can be gathered from the quote: "The Arpanet period is somewhat well documented because the corporation in charge – BBN – left a physical record. Source: Internet