THE WORLD ATLAS

Technology · 1969–1983

The Internet: ARPANET and TCP/IP

Boelter Hall, UCLA, Los Angeles (USA)

At 10:30 pm on 29 October 1969, UCLA student programmer Charley Kline tried to log in from a computer in Boelter Hall to a computer at the Stanford Research Institute over ARPANET, a network funded by the US Defense Department that broke messages into small "packets"; the remote machine crashed after two characters, so the first message ever sent was "lo", and the login worked about an hour later. During the 1970s Vint Cerf and Bob Kahn designed TCP/IP, a common set of rules that let separate networks join into one "network of networks", and on 1 January 1983, "flag day", ARPANET switched over to it for good, giving the Internet its common language.

See it on the map

Why it mattered

TCP/IP lets any computer network connect to any other, with no central control, so the Internet could grow from four computers in 1969 and 213 in 1981 to a single worldwide system. With the World Wide Web, email and later smartphones running on top of it, an estimated 6 billion people, about three-quarters of humanity, were using the Internet in 2025, transforming how people communicate, learn, shop, work and organise, although 2.2 billion remain offline.

Elsewhere

The World Wide Web, invented at CERN in 1989, is a service that runs on the Internet, not the Internet itself. ARPANET drew on the packet-switching ideas of Paul Baran in the US and Donald Davies in Britain.

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