ARPANET First Message
The first message was sent over ARPANET, the precursor to the internet
October 29, 1969
The Network That Became the Internet
On October 29, 1969, a message was sent between two computers for the first time over a network called ARPANET. The sending computer was at UCLA, and the receiving computer was at the Stanford Research Institute, about 350 miles away. The intended message was the word "login," but the system crashed after the first two letters were transmitted. The receiving computer got only "lo" before the connection failed. That partial message is now considered one of the most historic transmissions in technology history. ARPANET was funded by the U.S. Department of Defense's Advanced Research Projects Agency, which gave the network its name.
Why ARPANET Mattered
Before ARPANET, computers could not communicate with each other at all. Each machine was a standalone system. ARPANET introduced packet switching, a method of breaking data into small chunks called packets that travel independently across a network and reassemble at the destination. This was far more efficient and resilient than sending data as a single continuous stream. By 1971, ARPANET had 23 connected computers, or nodes, at universities and research institutions. Scientists began using it to share data, and the first email was sent over ARPANET in 1971 by Ray Tomlinson, who also chose the @ symbol to separate usernames from host names.
From Research Tool to Global Network
ARPANET kept growing through the 1970s and was eventually opened to civilian research institutions. In 1983, it adopted the TCP/IP protocol, the same fundamental communication standard that still powers the internet today. ARPANET was officially decommissioned in 1990, by which time the broader internet had taken over its functions. The World Wide Web, invented by Tim Berners-Lee in 1989, made the internet accessible to ordinary people by adding a visual, navigable layer on top of the underlying network. That first stumbling "lo" sent between two university computers in 1969 set in motion a chain of events that now connects billions of people worldwide.