The first ARPANET IMP log. The initials "CSK" in the log stand for Charles S. Kline, a student programmer at UCLA who was the first person to log in to a remote host via the military system. Image courtesy of UCLA

Oct. 29 (UPI) -- Tuesday marks the 50th anniversary of a milestone event that helped shape the modern Internet -- the first-ever computer linkup and the first electronic message sent over the U.S. Defense Department system, known then as ARPANET.

On Oct. 29, 1969, student programmers Charley Kline at the University of California-Los Angeles and Bill Duval at Stanford Research Institute transmitted the letters "LO" over an early network funded by the Advanced Research Projects Agency -- its acronym lending to the network's name.


"It was inadvertent, but it turned out to be prophetic and powerful that the message we delivered was 'LO,' as in 'lo and behold,'" said UCLA professor Leonard Kleinrock, who was hired to head the project.

What did the message mean?

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Kleinrock, a longtime computer networking expert, said Kline had attempted to type the word "login," but the system crashed after he typed the first two letters.

About an hour later, the team attempted the process again and successfully completed the login to connect the two locations in Los Angeles and Stanford, Calif., creating one of the earliest forms of the vast, globally connected network we use today. It's widely known today as the "first Internet connection."

The U.S. government started the ARPANET project in 1962 as a means to invest in computer research -- and as a response to the Soviet Union's historic launch of the first space satellite, Sputnik, five years earlier. It was one of the first packet-switching networks and the first to use the TCP/IP protocol.

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Marc Weber, curatorial director of the Computer History Museum's Internet History Program, told UPI that ARPA was funding programs throughout the country at the time, but researchers were unable to log into computers at different sites.

"The initial idea was just to save money and increase collaboration by having resource sharing where people at each ARPA site could log in and use the computers at other sites," he said. "The immediate need was resource sharing, the larger goal was to pioneer accessible network sharing."

Limited computer networking existed at the time, but it was prohibitively expensive due to the large, custom machines of the day.

Kleinrock said he envisioned ARPANET could capture the "spirit of community" by using computers to allow people to communicate with each other, remotely.

On that day in 1969, the Kline-Duval team became the first to connect two different kinds of general-purpose computers, a pioneering moment now recognized as a milestone event in the founding of the Internet.

"Bill and Charley were the first two users of the kind of networks we use today," Weber said. "On Oct. 29, 1969, there were two users of this general-purpose heterogeneous computer networks; now there's like 4 billion. And it went up from two exponentially for many decades until now."

ARPANET was decommissioned in 1990 but it laid the foundation of what would grow into the modern Internet. The World Wide Web, the information system that powers the modern Internet, was founded a year earlier by British scientist Tim Berners-Lee.