May 18, 2026

17 min read

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The programmer whose code underpins the Internet

Sharla Boehm, a math teacher, spent her summers coding. She’d go on to build what would eventually evolve into the Internet

By Katie Hafner, Samia Bouzid, Laura Isensee & The Lost Women of Science Initiative

Courtesy of Tenley Burke (image); Lily Whear (composite)

Sharla Boehm earned a teaching degree from the University of California, Los Angeles, before she channeled her talent for math into computer programming. While working at the RAND Corporation, she built a groundbreaking simulation, originally conceived to strengthen military communications during the cold war. The simulation—and her work—would ultimately lay the foundation for the modern Internet.

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TRANSCRIPT

Archival: What if a warning siren sounds? What should you do? Don’t hesitate. Find cover.

Katie Hafner: In the early 1960s, the United States and the Soviet Union were in a treacherous standoff. Each side was on high alert, with a growing stockpile of nuclear weapons — ready to launch at the first sign of an attack.

U.S. authorities weren’t just worried about how to weather an initial attack. They worried about how they would mount a counterattack if a bomb knocked out communications.

After all, these fragile systems were highly vulnerable to nuclear attack. If one bomb hit just right, all military communications could go down, leaving the entire country essentially defenseless.

So, the U.S. military put scientists to work. Their charge: to invent a communications network that could survive an attack. And on the team was one scientist who created an ingenious computer simulation — using 1960s-era computers.

Doug Rosenberg: As a piece of programming, it’s just unthinkable that she could do what she did. I mean, beyond comprehension.

Katie Hafner: And then, she would all but disappear into history as soon as her work was done.

Katie Hafner: This is Lost Women of Science. I’m Katie Hafner. And today we have the story of Sharla Perrine Boehm, a brilliant computer programmer — and so much more.

The simulation she created in the early 1960s wouldn’t just be offered up as a way to safeguard U.S. communications in the event of a nuclear attack… It was so ingenious that later, long after she left the field, her work would help bring about one of the most world-changing inventions ever: the internet.

But before we start, a mea culpa from me. In 1996, my book, Where Wizards Stay Up Late: The Origins Of The Internet, was published. It's a definitive history of the Arpanet, the network that would eventually evolve into the internet. And I never once mentioned Sharla — never even came across her name. Actually, that can’t be true. She co-authored a major paper, a paper I must have seen, and yet I never thought to ask, “Who is that?” It was always the famous man, her colleague Paul Baran, that I focused on.

And so, I want to make up for that today. And since I’m clearly not the expert when it comes to Sharla Perrine Boehm, I’ve brought in our producer Samia Bouzid to tell us Sharla’s story.

Samia Bouzid: On the night of November 24, 1961, it seemed like the nation’s worst nightmare had come to pass. The ballistic missile early warning systems across the U.S. went dead all at once. At a base in Omaha, officers on overnight duty tried to call communications headquarters in Colorado Springs — but the phone lines were dead too. That could mean one of two things: Either there had been some inexplicably vast communications failure, or the U.S. was under attack.

The officers scrambled to wake up General Thomas Power, the commander in chief of the Strategic Air Command, who immediately ordered nuclear forces on full alert. In the dark, bomber crews guided their planes onto runways. The U.S. was ready to strike.

But minutes later, the Strategic Air Command finally made contact with communications headquarters, by sending radar messages through a bomber that was already in the air. And headquarters reported that there was no attack. It was just a regular, quiet night.

So what happened? It turned out that a single motor at a relay station out in Colorado overheated and caused the entire system outage. It just happened to be the one relay station that all communications passed through.

So here was the United States, one command away from an accidental nuclear war… all because of some janky phone circuits. Clearly, something had to be done.

Paul Baran: This was the height of the Cold War.

Samia Bouzid: This is the co