Who Invented the Computer? Paul Baran, Robert Taylor, and ARPANET

Who Invented the Computer? This is the thirtieth installment in our ongoing series.

ARPANET gave birth to the internet.

When it comes to technological innovation, DARPA, the Defense Advanced Research Projects Agency, is second to none. Since its inception in late 1958, a whopping 70 percent of all tech advances are directly attributed to this tiny federal agency.

DARPA’s list of accomplishments is glitteringly impressive. It includes stealth planes and ships, the Global Positioning System, the open-source software TOR, and almost every aspect of modern computing.

Of all the advancements pioneered or prefigured by DARPA, however, the greatest is most certainly the internet. With more than 5 billion daily users, the Internet is the greatest information and communication tool ever devised.

The origin of the internet, like most scientific advances, is the product of multiple minds springboarding off of each other’s previously developed concepts and ideas. The two most important individuals in the creation of the internet are Paul Baran and Robert Taylor.

In 1964 Baran authored a paper setting forth the concept of information transmission over a digital network by breaking it into small packets that would be transmitted along phone lines on the path of least resistance and reassembled at a designated destination. He called the idea “hot-potato switching.”

Unfortunately for Baran, the U.S. military deemed his concept classified and stored it away. Fortunately for the world, it was stored at DARPA.


In the early 1960s, researchers developed “time-sharing,” a method that enabled multiple users to work on a computer at the same time. With time-sharing, the CPU would rapidly switch between different programs, running each one for a brief one-tenth of one second, so fast that users would not notice any pauses in their program.

While multiple users could be on a computer at the same time, there was a catch for remote users — each had to be connected to the CPU through a dedicated phone line. Having to log on to different computers through separate phone lines was too much for Robert Taylor in 1965, when he became the new director of DARPA’s Information Processing Techniques Office.

In Taylor’s office at the Pentagon, he had three terminals connected to three separate, remote time-sharing machines physically located at the Massachusetts Institute of Technology (“MIT”), the University of California, Berkley and the System Development Corporation in Santa Monica, Calif.

ARPANET gave birth to the internet.

Logging onto any of the three systems enabled Taylor to view who was using the systems at the various locations. As he watched the different systems and their user groups, he asked himself, “What if my one terminal was able to connect to all three mainframes and was able to communicate with other users?”

Taylor soon got to work recruiting a team and writing a plan to create a digital network that would link all 16 DARPA-funded universities and research centers without the need for dedicated phone connections between each computer on the network.

DARPA was originally established as a civilian agency called the “Advanced Research Projects Agency” with the acronym “ARPA.” Since it was stationed inside the Pentagon, however, it ended up under the control of the Defense Department and received its new name, the “Defense Advanced Research Projects,” or “DARPA.” By the late 1960s, DARPA was becoming increasingly focused on civilian projects and Taylor decided to reflect the change by naming his network project, “ARPANET.”

Baran’s Hot-potato Switching concept would become an essential component in making Taylor’s continent-spanning network operational. It was dusted off, tossed into the mix, and quickly and more appropriately named “packet-switching.”  

Taylor was unable to stick around to make certain his project was successful. In 1969 the White House asked him to head to Vietnam to establish a military computer center. Since he was certain ARPANET would work, he left the agency.


On Oct. 29, 1969, at 10:30 p.m. PST, UCLA student programmer Charley Kline, using the school’s computer, attempted to log onto the Stanford Research Institute’s (“SRI”) computer at Menlo Park, some 400 miles distant. Alas for Kline, the System crashed after he typed “Lo” instead of the intended word “Login.”  

Still, the message text “LO” was sent and received, providing ARPANET’s proof of concept. One hour later, after SRI’s computer was back up and running, and to the delight of everyone, a full login was successful.

ARPANET’s abilities were at first limited to three functions: Logging into a remote computer, printing to a remote printer, and transferring files between computers. Still, it was a giant leap forward for sharing information and communicating with distant users.

Within two months, University of California, Santa Barbra and the University of Utah connected to ARPANET. By April 1971, more institutes, including one at Oxford, London were part of ARPANET; and by 1976 there were a total of 35 nodes and 63 connected hosts sending academic articles and ideas digitally zipping back and forth across the country.

And We’re Off!

ARPANET gave birth to the internet.

With computer jockeys able to communicate easily with each other, it wasn’t long before ARPANET became the go-to arena for testing networking innovations like TELNET, file transfer protocols, and network control protocols. Virtual discussion groups sprang up as individuals with shared interests met one another online. The first group was SF-Lovers, dedicated to sci fi fans.

Not surprisingly, other computing networks were created and, in 1973, computer scientists Vinton Cerf and Bob Kahn created transmission-control protocol/internet protocol (“TCP/ICP”) to enable networks to communicate with one another.

In 1983, ARPANET was split into two parts: MILNET for the military and a civilian version of ARPANET. As TCP/ICP use became widespread, the word “internet” became the common term when referring to the two networks internetworking.

During the late 1980s, ARPANET’s importance began to decline with the advent of commercial online services like CompuServe, Prodigy, and Usenet. ARPANET was finally shut down in 1989 and formally decommissioned the next year.

Although ARPANET was in operation for only a few decades, it did change the world like no computer development before and ultimately, it opened the door for Tim Berners Lee (who we’ll get to someday) and his wondrous creation of the World Wide Web.

Would you like more insight into the history of hacking? Check out Calvin's other articles about historical hackery:
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GoCertify's mission is to help both students and working professionals get IT certifications. GoCertify was founded in 1998 by Anne Martinez.