29 October 1969 · UCLA, Los Angeles, California, USA
ARPANET: the birth of the internet
The first packet-based computer-to-computer message, sent from UCLA to the Stanford Research Institute — the characters "LO" before the system crashed — was the moment ARPANET, the embryo of today's global internet, came alive.
After the 1957 Sputnik shock, the U.S. Department of Defense established the advanced research agency ARPA (later DARPA). Under the shadow of the Cold War, designing a command-and-communications network that could survive nuclear attack was a priority. In the early 1960s the RAND analyst Paul Baran showed how easily centralised telephone networks could be disabled, and proposed "packet switching": breaking messages into small packets and sending them across the network on different paths, then reassembling at the destination. In Britain, Donald Davies developed the same idea independently.
In 1968 ARPA awarded the contract for the first routers — "Interface Message Processors" (IMPs) — to the company BBN. In September 1969 the first IMP was installed at UCLA. The second went to the Stanford Research Institute in October. On the evening of 29 October 1969, UCLA's Charley Kline tried to log in to a Stanford computer remotely. He typed "L" — it arrived. He typed "O" — it arrived. As he started to type "G" the system crashed. The first message sent was "LO" — a historical weight assumed by chance.
By 1971 ARPANET had 15 nodes; in 1973 it gained its first international links (Norway and England). That same year Vint Cerf and Bob Kahn began designing the TCP/IP protocol — the actual communication language of today's internet. In 1983 ARPANET migrated to TCP/IP, which some analysts call "the internet's true birthday." In 1989 Tim Berners-Lee invented the World Wide Web at CERN; the internet stopped being a closed academic-defence network and became a public space of information.
ARPANET was formally decommissioned in 1990; its legacy lives on in the TCP/IP backbone it spawned. Today there are about 5.5 billion internet users worldwide — two-thirds of the planet's population. The two letters sent from one IMP to another in 1969 were the starting signal of the deepest social, economic, and epistemic transformation of the following 55 years.
Location
UCLA, Los Angeles, California, USA · OpenStreetMap →
Sources
- Brief History of the Internet — Internet Society — Internet Society
- ARPANET — Computer History Museum — Computer History Museum
- Paul Baran and the Origins of the Internet — RAND Corporation — RAND Corporation