There is a version of tech history that starts with great men having great ideas. It is tidy, it is well-documented, and it is incomplete. The fuller version starts in the margins; in the notes scribbled alongside someone else’s work, in the rooms where the “clerical” calculations happened, in the jobs considered too tedious for anyone important to bother with. That is where a significant amount of the foundational work actually got done. And it was done, more often than the official history remembers, by women.
This is not a complete record. It is a reminder.
Ada Lovelace (1815–1852): the first algorithm, written in the margins
In the 1840s, an Italian mathematician named Luigi Menabrea wrote an article about Charles Babbage’s Analytical Engine, a mechanical computing machine that existed mostly as a concept and an ambition. Ada Lovelace, mathematician and daughter of Lord Byron, was asked to translate the article into English.
She did. And then she added notes.
Those notes ended up three times longer than the original article. They described, in precise detail, how the Engine could be programmed to calculate Bernoulli numbers, a sequence of steps that is now recognised as the world’s first algorithm written for a machine. More remarkably, Lovelace understood something Babbage himself hadn’t fully articulated: that the Engine’s potential went far beyond calculation. It could, she wrote, compose music, produce graphics, be used for any operation that could be expressed symbolically.
She was describing a general-purpose computer. In 1843.
Her notes were published under her initials (A.A.L.) and were largely forgotten for nearly a century, until Alan Turing referenced them in his own foundational work.
Grace Hopper (1906–1992): the woman who made computers speak human
In the late 1940s, programming a computer meant writing in machine code; long strings of ones and zeros that only the machine could read. Grace Hopper, a mathematician and US Navy officer, thought this was unnecessary. She believed computers could be programmed using words.
She was told it was impossible. Computers, she was informed, could only do arithmetic; they couldn’t understand English.
She built a compiler anyway. A compiler is a program that translates human-readable instructions into machine code, the thing that makes it possible to write code in something resembling a language rather than binary. Her first compiler, A-0, was completed in 1952. The concept she proved possible became the foundation of every programming language that followed, including COBOL, which she co-developed and which still runs significant portions of global banking and government systems today.
When asked later about being told it was impossible, she said she hadn’t known it was impossible, so she went ahead and did it.
Hedy Lamarr (1914–2000): the actress who invented the foundation of wireless communication
Hedy Lamarr was one of the most famous actresses in Hollywood in the 1940s. She was also, quietly, an inventor. During the Second World War, Lamarr co-developed a radio guidance system for torpedoes using frequency-hopping spread spectrum, a method of rapidly switching between radio frequencies to prevent enemies from jamming or intercepting signals. She and composer George Antheil patented the idea in 1942 and offered it to the US Navy.
The Navy declined. The patent eventually expired, unused and uncompensated.
Decades later, engineers working on secure wireless communications developed the same principle independently, and it became the technical foundation of WiFi, Bluetooth, and GPS. By the time Lamarr received any formal recognition, she was in her eighties. She died two years later. The wireless connection you are using right now exists, in part, because of work she was never properly credited for during her lifetime.
Katherine Johnson, Dorothy Vaughan & Mary Jackson: the women NASA couldn’t fly without (active 1950s–1960s)
At NASA in the 1950s, “computer” was a job title. It referred to the people, mostly women, many of them Black women, working in a segregated unit, who performed the complex mathematical calculations that the engineers and astronauts depended on. It was considered clerical work. It was essential work.
Katherine Johnson calculated the trajectories for the first American spaceflight and the Apollo 11 moon landing. When NASA began using electronic computers for orbital calculations, astronaut John Glenn refused to fly unless Johnson personally verified the computer’s numbers. She did. He flew.
Dorothy Vaughan taught herself and her team FORTRAN, an early programming language, when she recognised that electronic computers were going to replace human computers. She became NASA’s first Black supervisor and ensured her entire team had the skills to transition.
Mary Jackson became NASA’s first Black female engineer after fighting, successfully, for permission to take the advanced engineering courses held at a segregated school.
Their names were not on the early reports. Their unit worked in a separate building. Their contributions were classified, overlooked, or attributed elsewhere for decades, until a book and a film finally brought their stories to wider attention.
Joan Clarke (1917–1996): the codebreaker, they underpaid and undernamed
Joan Clarke was one of the most skilled codebreakers at Bletchley Park during the Second World War, part of the team led by Alan Turing, that cracked the Enigma cipher and is estimated to have shortened the war by several years.
She was recruited directly from Cambridge, where she had achieved a double first in mathematics. Cambridge did not award degrees to women at the time. She received a diploma instead.
At Bletchley, she was initially placed in a clerical role because women weren’t supposed to be doing the technical work. She was quickly moved to Hut 8, the naval Enigma section, where she worked directly alongside Turing and became deputy head of the unit. She was paid less than her male colleagues throughout.
After the war, the work at Bletchley remained classified for decades. When it was finally declassified, the story that emerged centred largely on Turing. Clarke’s name appeared in the footnotes.
Honourable mentions
The five women above are not the whole story. They are not even close to the whole story. The history of technology is full of names that didn’t make it into the textbooks; contributions that were absorbed into the work of others, patents that expired unclaimed, discoveries that were rediscovered and renamed. These are just a few more that deserve to be said out loud.
Margaret Hamilton wrote the flight software for NASA’s Apollo missions, code so robust it successfully handled an emergency during the Apollo 11 lunar landing. A photograph of her standing next to a printed stack of her code, as tall as she is, became one of the defining images of the space age.
Radia Perlman invented the Spanning Tree Protocol in 1985, which solved a fundamental problem in network design and made large-scale internet infrastructure possible. She is sometimes called the mother of the internet, a title she accepts with characteristic modesty.
Fei-Fei Li co-created ImageNet, the massive visual database that became the training ground for modern computer vision and triggered the deep learning revolution that drives today’s AI. The AI boom we are living through owes a significant debt to her work.
Reshma Saujani founded Girls Who Code in 2012, which has since reached over 500,000 girls with computer science education, directly addressing the pipeline problem that keeps women underrepresented in the field today.
What the margins were actually worth
The jobs nobody wanted. The clerical work. The translation with added notes. The calculations considered too tedious for the important people in the room. The roles that didn’t come with degrees, or credit, or equal pay, or sometimes even a seat at the table where the decisions were made.
That is where a significant amount of the foundation was laid.
The technology you use today, the wireless connection, the programming languages, the flight software, the AI systems, the internet infrastructure, runs, in part, on work that was done by women who were often paid less, credited less, and remembered less than the men working alongside them.
The history of technology was never only written by the people whose names ended up on the official reports.
It was also written in the margins.
If you liked this post, maybe you’ll also like Voices in the machine: women shaping the future of AI, which looks at the women leading AI and robotics today. If that previous post was about the present, the one you just read is about the foundation they were standing on; whether history remembered to tell them so or not.