Vacuum tube innovation of 1946 crossword clue

THE

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INNOVATORS

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ALSO BY WALTER ISAACSON

Steve Jobs American Sketches

Einstein: His Life and Universe A Benjamin Franklin Reader

Benjamin Franklin: An American Life Kissinger: A Biography

The Wise Men: Six Friends and the World They Made (with Evan Thomas) Pro and Con

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HOW A GROUP OF HACKERS, GENIUSES, AND GEEKS CREATED THE DIGITAL

REVOLUTION

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First published in Great Britain by Simon & Schuster UK Ltd, 2014 A CBS COMPANY

Copyright © 2014 by Walter Isaacson

This book is copyright under the Berne Convention. No reproduction without permission.

All rights reserved.

The right of Walter Isaacson to be identified as the author of this work has been asserted by him in accordance with sections 77 and 78 of the Copyright, Designs and Patents Act, 1988.

Simon & Schuster UK Ltd 1st Floor

222 Gray’s Inn Road London WC1X 8HB

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Simon & Schuster Australia, Sydney Simon & Schuster India, New Delhi

A CIP catalogue record for this book is available from the British Library

Excerpts from “All Watched Over by Machines of Loving Grace” from The Pill Versus the Springhill Mine Disaster by Richard Brautigan. Copyright © 1968 by Richard Brautigan. Reproduced by permission of Houghton Mifflin Harcourt Publishing Company. All rights reserved.

Photo research and editing by Laura Wyss, Wyssphoto, Inc., with the assistance of Elizabeth Seramur, Amy Hikida, and Emily Vinson, and by Jonathan Cox.

Interior design by Ruth Lee-Mui

ISBN: 978-1-47113-879-9 Ebook: 978-1-47113-881-2

The author and publishers have made all reasonable efforts to contact copyright-holders for permission, and apologise for any omissions or errors in the form of credits given. Corrections may be made to future printings.

Printed and bound by CPI Group (UK) Ltd, Croydon, CR0 4YY

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http://www.simonandschuster.co.uk
CONTENTS

Illustrated Timeline Introduction

CHAPTER 1

Ada, Countess of Lovelace CHAPTER 2

The Computer CHAPTER 3

Programming CHAPTER 4

The Transistor CHAPTER 5

The Microchip CHAPTER 6

Video Games CHAPTER 7

The Internet CHAPTER 8

The Personal Computer CHAPTER 9

Software CHAPTER 10

Online CHAPTER 11

The Web CHAPTER 12

Ada Forever

Acknowledgments Notes

Photo Credits

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Index

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THE

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INNOVATORS

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1800

1843

Ada, Countess of Lovelace, publishes “Notes” on Babbage’s Analytical Engine.

1847

George Boole creates a system using algebra for logical reasoning.

1890

The census is tabulated with Herman Hollerith’s punch-card machines.

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1931

Vannevar Bush devises the Differential Analyzer, an analog electromechanical computer.

1935

Tommy Flowers pioneers use of vacuum tubes as on-off switches in circuits.

1937

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Alan Turing publishes “On Computable Numbers,” describing a universal computer.

Claude Shannon describes how circuits of switches can perform tasks of Boolean algebra.

Bell Labs’ George Stibitz proposes a calculator using an electric circuit.

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Howard Aiken proposes construction of large digital computer and discovers parts of Babbage’s Difference Engine at Harvard.

John Vincent Atanasoff puts together concepts for an electronic computer during a long December night’s drive.

1938

William Hewlett and David Packard form company in Palo Alto garage.

1939

Atanasoff finishes model of electronic computer with mechanical storage drums.

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Turing arrives at Bletchley Park to work on breaking German codes.

1941

Konrad Zuse completes Z3, a fully functional electromechanical programmable digital computer.

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John Mauchly visits Atanasoff in Iowa, sees computer demonstrated.

1952

1942

Atanasoff completes partly working computer with three hundred vacuum tubes, leaves for Navy.

1943

Colossus, a vacuum-tube computer to break German codes, is completed at Bletchley Park.

1944

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Harvard Mark I goes into operation.

John von Neumann goes to Penn to work on ENIAC.

1945

Von Neumann writes “First Draft of a Report on the EDVAC” describing a stored-program computer.

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Six women programmers of ENIAC are sent to Aberdeen for training.

Vannevar Bush publishes “As We May Think,” describing personal computer.

Bush publishes “Science, the Endless Frontier,” proposing government funding of academic and industrial research.

ENIAC is fully operational.

1947

Transistor invented at Bell Labs.

1950

Turing publishes article describing a test for artificial intelligence.

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1952

Grace Hopper develops first computer compiler.

Von Neumann completes modern computer at the Institute for Advanced Study.

UNIVAC predicts Eisenhower election victory.

1954

1954

Turing commits suicide.

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Texas Instruments introduces silicon transistor and helps launch Regency radio.

1956

Shockley Semiconductor founded.

First artificial intelligence conference.

1957

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Robert Noyce, Gordon Moore, and others form Fairchild Semiconductor.

Russia launches Sputnik.

1958

Advanced Research Projects Agency (ARPA) announced.

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Jack Kilby demonstrates integrated circuit, or microchip.

1959

Noyce and Fairchild colleagues independently invent microchip.

1960

J. C. R. Licklider publishes “Man-Computer Symbiosis.”

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Paul Baran at RAND devises packet switching.

1961

President Kennedy proposes sending man to the moon.

1962

MIT hackers create Spacewar game.

Licklider becomes founding director of ARPA’s Information Processing Techniques Office.

Doug Engelbart publishes “Augmenting Human Intellect.”

1963

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Licklider proposes an “Intergalactic Computer Network.”

Engelbart and Bill English invent the mouse.

1972

1964

Ken Kesey and the Merry Pranksters take bus trip across America.

1965

Ted Nelson publishes first article about “hypertext.”

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Moore’s Law predicts microchips will double in power each year or so.

1966

Stewart Brand hosts Trips Festival with Ken Kesey.

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Bob Taylor convinces ARPA chief Charles Herzfeld to fund ARPANET.

Donald Davies coins the term packet switching.

1967

ARPANET design discussions in Ann Arbor and Gatlinburg.

1968

Larry Roberts sends out request for bids to build the ARPANET’s IMPs.

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Noyce and Moore form Intel, hire Andy Grove.

Brand publishes first Whole Earth Catalog.

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Engelbart stages the Mother of All Demos with Brand’s help.

1969

First nodes of ARPANET installed.

1971

Don Hoefler begins column for Electronic News called “Silicon Valley USA.”

Demise party for Whole Earth Catalog.

Intel 4004 microprocessor unveiled.

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Ray Tomlinson invents email.

1972

Nolan Bushnell creates Pong at Atari with Al Alcorn.

1973

1973

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Alan Kay helps to create the Alto at Xerox PARC.

Ethernet developed by Bob Metcalfe at Xerox PARC.

Community Memory shared terminal set up at Leopold’s Records, Berkeley.

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Vint Cerf and Bob Kahn complete TCP/IP protocols for the Internet.

1974

Intel 8080 comes out.

1975

Altair personal computer from MITS appears.

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Paul Allen and Bill Gates write BASIC for Altair, form Microsoft.

First meeting of Homebrew Computer Club.

Steve Jobs and Steve Wozniak launch the Apple I.

1977

The Apple II is released.

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1978

First Internet Bulletin Board System.

1979

Usenet newsgroups invented.

Jobs visits Xerox PARC.

1980

IBM commissions Microsoft to develop an operating system for PC.

1981

Hayes modem marketed to home users.

1983

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Microsoft announces Windows.

Richard Stallman begins developing GNU, a free operating system.

2011

1984

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Apple introduces Macintosh.

1985

Stewart Brand and Larry Brilliant launch The WELL.

CVC launches Q-Link, which becomes AOL.

1991

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Linus Torvalds releases first version of Linux kernel.

Tim Berners-Lee announces World Wide Web.

1993

Marc Andreessen announces Mosaic browser.

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Steve Case’s AOL offers direct access to the Internet.

1994

Justin Hall launches Web log and directory.

HotWired and Time Inc.’s Pathfinder become first major magazine publishers on Web.

1995

Ward Cunningham’s Wiki Wiki Web goes online.

1997

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IBM’s Deep Blue beats Garry Kasparov in chess.

1998

Larry Page and Sergey Brin launch Google.

1999

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Ev Williams launches Blogger.

2001

Jimmy Wales, with Larry Sanger, launches Wikipedia.

2011

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IBM’s computer Watson wins Jeopardy!

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INTRODUCTION

HOW THIS BOOK CAME TO BE

The computer and the Internet are among the most important inventions of our era, but few people know who created them. They were not conjured up in a garret or garage by solo inventors suitable to be singled out on magazine covers or put into a pantheon with Edison, Bell, and Morse. Instead, most of the innovations of the digital age were done collaboratively. There were a lot of fascinating people involved, some ingenious and a few even geniuses. This is the story of these pioneers, hackers, inventors, and entrepreneurs—who they were, how their minds worked, and what made them so creative. It’s also a narrative of how they collaborated and why their ability to work as teams made them even more creative.

The tale of their teamwork is important because we don’t often focus on how central that skill is to innovation. There are thousands of books celebrating people we biographers portray, or mythologize, as lone inventors. I’ve produced a few myself. Search the phrase “the man who invented” on Amazon and you get 1,860 book results. But we have far fewer tales of collaborative creativity, which is actually more important in understanding how today’s technology revolution was fashioned. It can also be more interesting.

We talk so much about innovation these days that it has become a buzzword, drained of clear meaning. So in this book I set out to report on how innovation actually happens in the real world. How did the most imaginative innovators of our time turn disruptive ideas into realities? I focus on a dozen or so of the most significant breakthroughs of the digital age and the people who made them. What ingredients produced their creative leaps? What skills proved most useful? How did they lead and collaborate? Why did some succeed and others fail?

I also explore the social and cultural forces that provide the atmosphere for innovation. For the birth of the digital age, this included a research ecosystem that was nurtured by government spending and managed by a military-industrial-academic collaboration. Intersecting with that was a loose alliance of community organizers, communal-minded hippies, do-it-yourself hobbyists, and homebrew hackers, most of whom were suspicious of centralized authority.

Histories can be written with a different emphasis on any of these factors. An example is the invention of the Harvard/IBM Mark I, the first big electromechanical computer. One of its programmers, Grace Hopper, wrote a history that focused on its primary creator, Howard Aiken. IBM countered with a history that featured its teams of faceless engineers who contributed the incremental innovations, from counters to card feeders, that went into the machine.

Likewise, what emphasis should be put on great individuals versus on cultural currents has long been a matter of dispute; in the mid-nineteenth century, Thomas Carlyle declared that “the history of the world is but the biography of great men,” and Herbert Spencer responded with a theory that emphasized the role of societal forces. Academics and participants often view this balance differently. “As a professor, I tended to think of history as run by impersonal forces,” Henry Kissinger told reporters during one of his Middle East shuttle missions in the 1970s. “But when you see it in practice, you see the difference personalities make.”1 When it comes to digital-age innovation, as with Middle East peacemaking, a variety

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of personal and cultural forces all come into play, and in this book I sought to weave them together.

The Internet was originally built to facilitate collaboration. By contrast, personal computers, especially those meant to be used at home, were devised as tools for individual creativity. For more than a decade, beginning in the early 1970s, the development of networks and that of home computers proceeded separately from one another. They finally began coming together in the late 1980s with the advent of modems, online services, and the Web. Just as combining the steam engine with ingenious machinery drove the Industrial Revolution, the combination of the computer and distributed networks led to a digital revolution that allowed anyone to create, disseminate, and access any information anywhere.

Historians of science are sometimes wary about calling periods of great change revolutions, because they prefer to view progress as evolutionary. “There was no such thing as the Scientific Revolution, and this is a book about it,” is the wry opening sentence of the Harvard professor Steven Shapin’s book on that period. One method that Shapin used to escape his half-joking contradiction is to note how the key players of the period “vigorously expressed the view” that they were part of a revolution. “Our sense of radical change afoot comes substantially from them.”2

Likewise, most of us today share a sense that the digital advances of the past half century are transforming, perhaps even revolutionizing the way we live. I can recall the excitement that each new breakthrough engendered. My father and uncles were electrical engineers, and like many of the characters in this book I grew up with a basement workshop that had circuit boards to be soldered, radios to be opened, tubes to be tested, and boxes of transistors and resistors to be sorted and deployed. As an electronics geek who loved Heathkits and ham radios (WA5JTP), I can remember when vacuum tubes gave way to transistors. At college I learned programming using punch cards and recall when the agony of batch processing was replaced by the ecstasy of hands-on interaction. In the 1980s I thrilled to the static and screech that modems made when they opened for you the weirdly magical realm of online services and bulletin boards, and in the early 1990s I helped to run a digital division at Time and Time Warner that launched new Web and broadband Internet services. As Wordsworth said of the enthusiasts who were present at the beginning of the French Revolution, “Bliss was it in that dawn to be alive.”

I began work on this book more than a decade ago. It grew out of my fascination with the digital-age advances I had witnessed and also from my biography of Benjamin Franklin, who was an innovator, inventor, publisher, postal service pioneer, and all-around information networker and entrepreneur. I wanted to step away from doing biographies, which tend to emphasize the role of singular individuals, and once again do a book like The Wise Men, which I had coauthored with a colleague about the creative teamwork of six friends who shaped America’s cold war policies. My initial plan was to focus on the teams that invented the Internet. But when I interviewed Bill Gates, he convinced me that the simultaneous emergence of the Internet and the personal computer made for a richer tale. I put this book on hold early in 2009, when I began working on a biography of Steve Jobs. But his story reinforced my interest in how the development of the Internet and computers intertwined, so as soon as I finished that book, I went back to work on this tale of digital-age innovators.

The protocols of the Internet were devised by peer collaboration, and the resulting system seemed to have embedded in its genetic code a propensity to facilitate such collaboration. The power to create and transmit information was fully distributed to each of the nodes, and any attempt to impose controls or a hierarchy could be routed around. Without falling into the teleological fallacy of ascribing intentions or a personality to technology, it’s fair to say that a

43

system of open networks connected to individually controlled computers tended, as the printing press did, to wrest control over the distribution of information from gatekeepers, central authorities, and institutions that employed scriveners and scribes. It became easier for ordinary folks to create and share content.

The collaboration that created the digital age was not just among peers but also between generations. Ideas were handed off from one cohort of innovators to the next. Another theme that emerged from my research was that users repeatedly commandeered digital innovations to create communications and social networking tools. I also became interested in how the quest for artificial intelligence—machines that think on their own—has consistently proved less fruitful than creating ways to forge a partnership or symbiosis between people and machines. In other words, the collaborative creativity that marked the digital age included collaboration between humans and machines.

Finally, I was struck by how the truest creativity of the digital age came from those who were able to connect the arts and sciences. They believed that beauty mattered. “I always thought of myself as a humanities person as a kid, but I liked electronics,” Jobs told me when I embarked on his biography. “Then I read something that one of my heroes, Edwin Land of Polaroid, said about the importance of people who could stand at the intersection of humanities and sciences, and I decided that’s what I wanted to do.” The people who were comfortable at this humanities-technology intersection helped to create the human-machine symbiosis that is at the core of this story.

Like many aspects of the digital age, this idea that innovation resides where art and science connect is not new. Leonardo da Vinci was the exemplar of the creativity that flourishes when the humanities and sciences interact. When Einstein was stymied while working out General Relativity, he would pull out his violin and play Mozart until he could reconnect to what he called the harmony of the spheres.

When it comes to computers, there is one other historical figure, not as well known, who embodied the combination of the arts and sciences. Like her famous father, she understood the romance of poetry. Unlike him, she also saw the romance of math and machinery. And that is where our story begins.

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Ada, Countess of Lovelace (1815–52), painted by Margaret Sarah Carpenter in 1836.

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Lord Byron (1788–1824), Ada’s father, in Albanian dress, painted by Thomas Phillips in 1835.

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Charles Babbage (1791–1871), photograph taken circa 1837.

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CHAPTER ONE

ADA, COUNTESS OF LOVELACE

POETICAL SCIENCE In May 1833, when she was seventeen, Ada Byron was among the young women presented at the British royal court. Family members had worried about how she would acquit herself, given her high-strung and independent nature, but she ended up behaving, her mother reported, “tolerably well.” Among those Ada met that evening were the Duke of Wellington, whose straightforward manner she admired, and the seventy-nine-year-old French ambassador Talleyrand, who struck her as “an old monkey.”1

The only legitimate child of the poet Lord Byron, Ada had inherited her father’s romantic spirit, a trait that her mother tried to temper by having her tutored in mathematics. The combination produced in Ada a love for what she took to calling “poetical science,” which linked her rebellious imagination to her enchantment with numbers. For many, including her father, the rarefied sensibilities of the Romantic era clashed with the techno-excitement of the Industrial Revolution. But Ada was comfortable at the intersection of both eras.

So it was not surprising that her debut at court, despite the glamour of the occasion, made less impression on her than her attendance a few weeks later at another majestic event of the London season, at which she met Charles Babbage, a forty-one-year-old widowed science and math eminence who had established himself as a luminary on London’s social circuit. “Ada was more pleased with a party she was at on Wednesday than with any of the assemblages in the grand monde,” her mother reported to a friend. “She met there a few scientific people—amongst them Babbage, with whom she was delighted.”2

Babbage’s galvanizing weekly salons, which included up to three hundred guests, brought together lords in swallow-tail coats and ladies in brocade gowns with writers, industrialists, poets, actors, statesmen, explorers, botanists, and other “scientists,” a word that Babbage’s friends had recently coined.3 By bringing scientific scholars into this exalted realm, said one noted geologist, Babbage “successfully asserted the rank in society due to science.”4

The evenings featured dancing, readings, games, and lectures accompanied by an assortment of seafood, meat, fowl, exotic drinks, and iced desserts. The ladies staged tableaux vivants, in which they dressed in costume to re-create famous paintings. Astronomers set up telescopes, researchers displayed their electrical and magnetic contrivances, and Babbage allowed guests to play with his mechanical dolls. The centerpiece of the evenings—and one of Babbage’s many motives for hosting them—was his demonstration of a model portion of his Difference Engine, a mammoth mechanical calculating contraption that he was building in a fireproof structure adjacent to his home. Babbage would display the model with great drama, cranking its arm as it calculated a sequence of numbers and, just as the audience began to get bored, showed how the pattern could suddenly change based on instructions that had been coded into the machine.5 Those who were especially intrigued would be invited through the yard to the former stables, where the complete machine was being constructed.

Babbage’s Difference Engine, which could solve polynomial equations, impressed people in different ways. The Duke of Wellington commented that it could be useful in analyzing the variables a general might face before going into battle.6 Ada’s mother, Lady Byron, marveled

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that it was a “thinking machine.” As for Ada, who would later famously note that machines could never truly think, a friend who went with them to the demonstration reported, “Miss Byron, young as she was, understood its working, and saw the great beauty of the invention.”7

Ada’s love of both poetry and math primed her to see beauty in a computing machine. She was an exemplar of the era of Romantic science, which was characterized by a lyrical enthusiasm for invention and discovery. It was a period that brought “imaginative intensity and excitement to scientific work,” Richard Holmes wrote in The Age of Wonder. “It was driven by a common ideal of intense, even reckless, personal commitment to discovery.”8

In short, it was a time not unlike our own. The advances of the Industrial Revolution, including the steam engine, mechanical loom, and telegraph, transformed the nineteenth century in much the same way that the advances of the Digital Revolution—the computer, microchip, and Internet—have transformed our own. At the heart of both eras were innovators who combined imagination and passion with wondrous technology, a mix that produced Ada’s poetical science and what the twentieth-century poet Richard Brautigan would call “machines of loving grace.”

LORD BYRON Ada inherited her poetic and insubordinate temperament from her father, but he was not the source of her love for machinery. He was, in fact, a Luddite. In his maiden speech in the House of Lords, given in February 1812 when he was twenty-four, Byron defended the followers of Ned Ludd, who were rampaging against mechanical weaving machines. With sarcastic scorn Byron mocked the mill owners of Nottingham, who were pushing a bill that would make destroying automated looms a crime punishable by death. “These machines were to them an advantage, inasmuch as they superseded the necessity of employing a number of workmen, who were left in consequence to starve,” Byron declared. “The rejected workmen, in the blindness of their ignorance, instead of rejoicing at these improvements in arts so beneficial to mankind, conceived themselves to be sacrificed to improvements in mechanism.”

Two weeks later, Byron published the first two cantos of his epic poem Childe Harold’s Pilgrimage, a romanticized account of his wanderings through Portugal, Malta, and Greece, and, as he later remarked, “awoke one morning and found myself famous.” Beautiful, seductive, troubled, brooding, and sexually adventurous, he was living the life of a Byronic hero while creating the archetype in his poetry. He became the toast of literary London and was feted at three parties each day, most memorably a lavish morning dance hosted by Lady Caroline Lamb.

Lady Caroline, though married to a politically powerful aristocrat who was later prime minister, fell madly in love with Byron. He thought she was “too thin,” yet she had an unconventional sexual ambiguity (she liked to dress as a page boy) that he found enticing. They had a turbulent affair, and after it ended she stalked him obsessively. She famously declared him to be “mad, bad, and dangerous to know,” which he was. So was she.

At Lady Caroline’s party, Lord Byron had also noticed a reserved young woman who was, he recalled, “more simply dressed.” Annabella Milbanke, nineteen, was from a wealthy and multi-titled family. The night before the party, she had read Childe Harold and had mixed feelings. “He is rather too much of a mannerist,” she wrote. “He excels most in the delineation of deep feeling.” Upon seeing him across the room at the party, her feelings were conflicted, dangerously so. “I did not seek an introduction to him, for all the women were absurdly courting him, and trying to deserve the lash of his Satire,” she wrote her mother. “I am not desirous of a place in his lays. I made no offering at the shrine of Childe Harold,

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though I shall not refuse the acquaintance if it comes my way.”9 That acquaintance, as it turned out, did come her way. After he was introduced to her

formally, Byron decided that she might make a suitable wife. It was, for him, a rare display of reason over romanticism. Rather than arousing his passions, she seemed to be the sort of woman who might tame those passions and protect him from his excesses—as well as help pay off his burdensome debts. He proposed to her halfheartedly by letter. She sensibly declined. He wandered off to far less appropriate liaisons, including one with his half sister, Augusta Leigh. But after a year, Annabella rekindled the courtship. Byron, falling more deeply in debt while grasping for a way to curb his enthusiasms, saw the rationale if not the romance in the possible relationship. “Nothing but marriage and a speedy one can save me,” he admitted to Annabella’s aunt. “If your niece is obtainable, I should prefer her; if not, the very first woman who does not look as if she would spit in my face.”10 There were times when Lord Byron was not a romantic. He and Annabella were married in January 1815.

Byron initiated the marriage in his Byronic fashion. “Had Lady Byron on the sofa before dinner,” he wrote about his wedding day.11 Their relationship was still active when they visited his half sister two months later, because around then Annabella got pregnant. However, during the visit she began to suspect that her husband’s friendship with Augusta went beyond the fraternal, especially after he lay on a sofa and asked them both to take turns kissing him.12 The marriage started to unravel.

Annabella had been tutored in mathematics, which amused Lord Byron, and during their courtship he had joked about his own disdain for the exactitude of numbers. “I know that two and two make four—and should be glad to prove it too if I could,” he wrote, “though I must say if by any sort of process I could convert two and two into five it would give me much greater pleasure.” Early on, he affectionately dubbed her the “Princess of Parallelograms.” But when the marriage began to sour, he refined that mathematical image: “We are two parallel lines prolonged to infinity side by side but never to meet.” Later, in the first canto of his epic poem Don Juan, he would mock her: “Her favourite science was the mathematical. . . . She was a walking calculation.”

The marriage was not saved by the birth of their daughter on December 10, 1815. She was named Augusta Ada Byron, her first name that of Byron’s too-beloved half sister. When Lady Byron became convinced of her husband’s perfidy, she thereafter called her daughter by her middle name. Five weeks later she packed her belongings into a carriage and fled to her parents’ country home with the infant Ada.

Ada never saw her father again. Lord Byron left the country that April after Lady Byron, in letters so calculating that she earned his sobriquet of “Mathematical Medea,” threatened to expose his alleged incestuous and homosexual affairs as a way to secure a separation agreement that gave her custody of their child.13

The opening of canto 3 of Childe Harold, written a few weeks later, invokes Ada as his muse: Is thy face like thy mother’s, my fair child! Ada! sole daughter of my house and of my heart? When last I saw thy young blue eyes they smiled, And then we parted.

Byron wrote these lines in a villa by Lake Geneva, where he was staying with the poet Percy Bysshe Shelley and Shelley’s future wife, Mary. It rained relentlessly. Trapped inside for days, Byron suggested they write horror stories. He produced a fragment of a tale about a vampire, one of the first literary efforts on that subject, but Mary’s story was the one that became a classic: Frankenstein, or The Modern Prometheus. Playing on the ancient Greek myth of the hero who crafted a living man out of clay and snatched fire from the gods for human use, Frankenstein was the story of a scientist who galvanized a man-made assemblage

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into a thinking human. It was a cautionary tale about technology and science. It also raised the question that would become associated with Ada: Can man-made machines ever truly think?

The third canto of Childe Harold ends with Byron’s prediction that Annabella would try to keep Ada from knowing about her father, and so it happened. There was a portrait of Lord Byron at their house, but Lady Byron kept it securely veiled, and Ada never saw it until she was twenty.14

Lord Byron, by contrast, kept a picture of Ada on his desk wherever he wandered, and his letters often requested news or portraits of her. When she was seven, he wrote to Augusta, “I wish you would obtain from Lady B some accounts of Ada’s disposition. . . . Is the girl imaginative? . . . Is she passionate? I hope that the Gods have made her anything save poetical—it is enough to have one such fool in the family.” Lady Byron reported that Ada had an imagination that was “chiefly exercised in connection with her mechanical ingenuity.”15

Around that time, Byron, who had been wandering through Italy, writing and having an assortment of affairs, grew bored and decided to enlist in the Greek struggle for independence from the Ottoman Empire. He sailed for Missolonghi, where he took command of part of the rebel army and prepared to attack a Turkish fortress. But before he could engage in battle, he caught a violent cold that was made worse by his doctor’s decision to treat him by bloodletting. On April 19, 1824, he died. According to his valet, among his final words were “Oh, my poor dear child!—my dear Ada! My God, could I have seen her! Give her my blessing.”16

ADA Lady Byron wanted to make sure that Ada did not turn out like her father, and part of her strategy was to have the girl rigorously study math, as if it were an antidote to poetic imagination. When Ada, at age five, showed a preference for geography, Lady Byron ordered that the subject be replaced by additional arithmetic lessons, and her governess soon proudly reported, “She adds up sums of five or six rows of figures with accuracy.” Despite these efforts, Ada developed some of her father’s propensities. She had an affair as a young teenager with one of her tutors, and when they were caught and the tutor banished, she tried to run away from home to be with him. In addition, she had mood swings that took her from feelings of grandiosity to despair, and she suffered various maladies both physical and psychological.

Ada accepted her mother’s conviction that an immersion in math could help tame her Byronic tendencies. After her dangerous liaison with her tutor, and inspired by Babbage’s Difference Engine, she decided on her own, at eighteen, to begin a new series of lessons. “I must cease to think of living for pleasure or self-gratification,” she wrote her new tutor. “I find that nothing but very close and intense application to subjects of a scientific nature now seems to keep my imagination from running wild. . . . It appears to me that the first thing is to go through a course of Mathematics.” He agreed with the prescription: “You are right in supposing that your chief resource and safeguard at the present is in a course of severe intellectual study. For this purpose there is no subject to be compared to Mathematics.”17 He prescribed Euclidean geometry, followed by a dose of trigonometry and algebra. That should cure anyone, they both thought, from having too many artistic or romantic passions.

Her interest in technology was stoked when her mother took her on a trip through the British industrial midlands to see the new factories and machinery. Ada was particularly impressed with an automated weaving loom that used punch cards to direct the creation of the desired fabric patterns, and she drew a sketch of how it worked. Her father’s famous speech

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in the House of Lords had defended the Luddites who had smashed such looms because of their fear of what technology might inflict on humanity. But Ada waxed poetical about them and saw the connection with what would someday be called computers. “This Machinery reminds me of Babbage and his gem of all mechanism,” she wrote.18

Ada’s interest in applied science was further stimulated when she met one of Britain’s few noted female mathematicians and scientists, Mary Somerville. Somerville had just finished writing one of her great works, On the Connexion of the Physical Sciences, in which she tied together developments in astronomy, optics, electricity, chemistry, physics, botany, and geology.1 Emblematic of the time, it provided a unified sense of the extraordinary endeavors of discovery that were under way. She proclaimed in her opening sentence, “The progress of modern science, especially within the last five years, has been remarkable for a tendency to simplify the laws of nature and to unite detached branches by general principles.”

Somerville became a friend, teacher, inspiration, and mentor to Ada. She met with Ada regularly, sent her math books, devised problems for her to solve, and patiently explained the correct answers. She was also a good friend of Babbage’s, and during the fall of 1834 she and Ada would often visit his Saturday-evening salons. Somerville’s son, Woronzow Greig, aided Ada’s efforts to settle down by suggesting to one of his former classmates at Cambridge that she would make a suitable—or at least interesting—wife.

William King was socially prominent, financially secure, quietly intelligent, and as taciturn as Ada was excitable. Like her, he was a student of science, but his focus was more practical and less poetic: his primary interests were crop rotation theories and advances in livestock breeding techniques. He proposed marriage within a few weeks of meeting Ada, and she accepted. Her mother, with motives that only a psychiatrist could fathom, decided it was imperative to tell William about Ada’s attempted elopement with her tutor. Despite this news, William was willing to proceed with the wedding, which was held in July 1835. “Gracious God, who has so mercifully given you an opportunity of turning aside from the dangerous paths, has given you a friend and guardian,” Lady Byron wrote her daughter, adding that she should use this opportunity to “bid adieu” to all of her “peculiarities, caprices, and self- seeking.”19

The marriage was a match made in rational calculus. For Ada, it offered the chance to adopt a more steady and grounded life. More important, it allowed her to escape dependence on her domineering mother. For William, it meant having a fascinating, eccentric wife from a wealthy and famous family.

Lady Byron’s first cousin Viscount Melbourne (who had the misfortune of having been married to Lady Caroline Lamb, by then deceased) was the prime minister, and he arranged that, in Queen Victoria’s coronation list of honors, William would become the Earl of Lovelace. His wife thus became Ada, Countess of Lovelace. She is therefore properly referred to as Ada or Lady Lovelace, though she is now commonly known as Ada Lovelace.

That Christmas of 1835, Ada received from her mother the family’s life-size portrait of her father. Painted by Thomas Phillips, it showed Lord Byron in romantic profile, gazing at the horizon, dressed in traditional Albanian costume featuring a red velvet jacket, ceremonial sword, and headdress. For years it had hung over Ada’s grandparents’ mantelpiece, but it had been veiled by a green cloth from the day her parents had separated. Now she was trusted not only to see it but to possess it, along with his inkstand and pen.

Her mother did something even more surprising when the Lovelaces’ first child, a son, was born a few months later. Despite her disdain for her late husband’s memory, she agreed that Ada should name the boy Byron, which she did. The following year Ada had a daughter, whom she dutifully named Annabella, after her mother. Ada then came down with yet another mysterious malady, which kept her bedridden for months. She recovered well enough

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to have a third child, a son named Ralph, but her health remained fragile. She had digestive and respiratory problems that were compounded by being treated with laudanum, morphine, and other forms of opium, which led to mood swings and occasional delusions.

Ada was further unsettled by the eruption of a personal drama that was bizarre even by the standards of the Byron family. It involved Medora Leigh, the daughter of Byron’s half sister and occasional lover. According to widely accepted rumors, Medora was Byron’s daughter. She seemed determined to show that darkness ran in the family. She had an affair with a sister’s husband, then ran off with him to France and had two illegitimate children. In a fit of self-righteousness, Lady Byron went to France to rescue Medora, then revealed to Ada the story of her father’s incest.

This “most strange and dreadful history” did not seem to surprise Ada. “I am not in the least astonished,” she wrote her mother. “You merely confirm what I have for years and years felt scarcely a doubt about.”20 Rather than being outraged, she seemed oddly energized by the news. She declared that she could relate to her father’s defiance of authority. Referring to his “misused genius,” she wrote to her mother, “If he has transmitted to me any portion of that genius, I would use it to bring out great truths and principles. I think he has bequeathed this task to me. I have this feeling strongly, and there is a pleasure attending it.”21

Once again Ada took up the study of math in order to settle herself, and she tried to convince Babbage to become her tutor. “I have a peculiar way of learning, and I think it must be a peculiar man to teach me successfully,” she wrote him. Whether due to her opiates or her breeding or both, she developed a somewhat outsize opinion of her own talents and began to describe herself as a genius. In her letter to Babbage, she wrote, “Do not reckon me conceited, . . . but I believe I have the power of going just as far as I like in such pursuits, and where there is so decided a taste, I should almost say a passion, as I have for them, I question if there is not always some portion of natural genius even.”22

Babbage deflected Ada’s request, which was probably wise. It preserved their friendship for an even more important collaboration, and she was able to secure a first-rate math tutor instead: Augustus De Morgan, a patient gentleman who was a pioneer in the field of symbolic logic. He had propounded a concept that Ada would one day employ with great significance, which was that an algebraic equation could apply to things other than numbers. The relations among symbols (for example, that a + b = b + a) could be part of a logic that applied to things that were not numerical.

Ada was never the great mathematician that her canonizers claim, but she was an eager pupil, able to grasp most of the basic concepts of calculus, and with her artistic sensibility she liked to visualize the changing curves and trajectories that the equations were describing. De Morgan encouraged her to focus on the rules for working through equations, but she was more eager to discuss the underlying concepts. Likewise with geometry, she often asked for visual ways to picture problems, such as how the intersections of circles in a sphere divide it into various shapes.

Ada’s ability to appreciate the beauty of mathematics is a gift that eludes many people, including some who think of themselves as intellectual. She realized that math was a lovely language, one that describes the harmonies of the universe and can be poetic at times. Despite her mother’s efforts, she remained her father’s daughter, with a poetic sensibility that allowed her to view an equation as a brushstroke that painted an aspect of nature’s physical splendor, just as she could visualize the “wine-dark sea” or a woman who “walks in beauty, like the night.” But math’s appeal went even deeper; it was spiritual. Math “constitutes the language through which alone we can adequately express the great facts of the natural world,” she said, and it allows us to portray the “changes of mutual relationship” that unfold in creation. It is “the instrument through which the weak mind of man can most effectually read his Creator’s works.”

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This ability to apply imagination to science characterized the Industrial Revolution as well as the computer revolution, for which Ada was to become a patron saint. She was able, as she told Babbage, to understand the connection between poetry and analysis in ways that transcended her father’s talents. “I do not believe that my father was (or ever could have been) such a Poet as I shall be an Analyst; for with me the two go together indissolubly,” she wrote.23

Her reengagement with math, she told her mother, spurred her creativity and led to an “immense development of imagination, so much so that I feel no doubt if I continue my studies I shall in due time be a Poet.”24 The whole concept of imagination, especially as it was applied to technology, intrigued her. “What is imagination?” she asked in an 1841 essay. “It is the Combining faculty. It brings together things, facts, ideas, conceptions in new, original, endless, ever-varying combinations. . . . It is that which penetrates into the unseen worlds around us, the worlds of Science.”25

By then Ada believed she possessed special, even supernatural abilities, what she called “an intuitive perception of hidden things.” Her exalted view of her talents led her to pursue aspirations that were unusual for an aristocratic woman and mother in the early Victorian age. “I believe myself to possess a most singular combination of qualities exactly fitted to make me pre-eminently a discoverer of the hidden realities of nature,” she explained in a letter to her mother in 1841. “I can throw rays from every quarter of the universe into one vast focus.”26

It was while in this frame of mind that she decided to engage again with Charles Babbage, whose salons she had first attended eight years earlier.

CHARLES BABBAGE AND HIS ENGINES From an early age, Charles Babbage had been interested in machines that could perform human tasks. When he was a child, his mother took him to many of the exhibition halls and museums of wonder that were springing up in London in the early 1800s. At one in Hanover Square, a proprietor aptly named Merlin invited him up to the attic workshop where there was a variety of mechanical dolls, known as “automata.” One was a silver female dancer, about a foot tall, whose arms moved with grace and who held in her hand a bird that could wag its tail, flap its wings, and open its beak. The Silver Lady’s ability to display feelings and personality captured the boy’s fancy. “Her eyes were full of imagination,” he recalled. Years later he discovered the Silver Lady at a bankruptcy auction and bought it. It served as an amusement at his evening salons where he celebrated the wonders of technology.

At Cambridge Babbage became friends with a group, including John Herschel and George Peacock, who were disappointed by the way math was taught there. They formed a club, called the Analytical Society, which campaigned to get the university to abandon the calculus notation devised by its alumnus Newton, which relied on dots, and replace it with the one devised by Leibniz, which used dx and dy to represent infinitesimal increments and was thus known as “d” notation. Babbage titled their manifesto “The Principles of pure D-ism in opposition to the Dot-age of the University.”27 He was prickly, but he had a good sense of humor.

One day Babbage was in the Analytical Society’s room working on a table of logarithms that was littered with discrepancies. Herschel asked him what he was thinking. “I wish to God these calculations had been executed by steam,” Babbage answered. To this idea of a mechanical method for tabulating logarithms Herschel replied, “It is quite possible.”28 In 1821 Babbage turned his attention to building such a machine.

Over the years, many had fiddled with making calculating contraptions. In the 1640s, Blaise Pascal, the French mathematician and philosopher, created a mechanical calculator to

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reduce the drudgery of his father’s work as a tax supervisor. It had spoked metal wheels with the digits 0 through 9 on their circumference. To add or subtract numbers, the operator used a stylus to dial a number, as if using a rotary phone, then dialed in the next number; an armature carried or borrowed a 1 when necessary. It became the first calculator to be patented and sold commercially.

Thirty years later, Gottfried Leibniz, the German mathematician and philosopher, tried to improve upon Pascal’s contraption with a “stepped reckoner” that had the capacity to multiply and divide. It had a hand-cranked cylinder with a set of teeth that meshed with counting wheels. But Leibniz ran into a problem that would be a recurring theme of the digital age. Unlike Pascal, an adroit engineer who could combine scientific theories with mechanical genius, Leibniz had little engineering skill and did not surround himself with those who did. So, like many great theorists who lacked practical collaborators, he was unable to produce reliably working versions of his device. Nevertheless, his core concept, known as the Leibniz wheel, would influence calculator design through the time of Babbage.

Babbage knew of the devices of Pascal and Leibniz, but he was trying to do something more complex. He wanted to construct a mechanical method for tabulating logarithms, sines, cosines, and tangents.2 To do so, he adapted an idea that the French mathematician Gaspard de Prony came up with in the 1790s. In order to create logarithm and trigonometry tables, de Prony broke down the operations into very simple steps that involved only addition and subtraction. Then he provided easy instructions so that scores of human laborers, who knew little math, could perform these simple tasks and pass along their answers to the next set of laborers. In other words, he created an assembly line, the great industrial-age innovation that was memorably analyzed by Adam Smith in his description of the division of labor in a pin- making factory. After a trip to Paris in which he heard of de Prony’s method, Babbage wrote, “I conceived all of a sudden the idea of applying the same method to the immense work with which I had been burdened, and to manufacture logarithms as one manufactures pins.”29

Even complex mathematical tasks, Babbage realized, could be broken into steps that came down to calculating “finite differences” through simple adding and subtracting. For example, in order to make a table of squares—12, 22, 32, 42, and so on—you could list the initial numbers in such a sequence: 1, 4, 9, 16. . . . This would be column A. Beside it, in column B, you could figure out the differences between each of these numbers, in this case 3, 5, 7, 9. . . . Column C would list the difference between each of column B’s numbers, which is 2, 2, 2, 2. . . . Once the process was thus simplified, it could be reversed and the tasks parceled out to untutored laborers. One would be in charge of adding 2 to the last number in column B, and then would hand that result to another person, who would add that result to the last number in column A, thus generating the next number in the sequence of squares.

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Replica of the Difference Engine.

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Replica of the Analytical Engine.

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The Jacquard loom.

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Silk portrait of Joseph-Marie Jacquard (1752–1834) woven by a Jacquard loom.

Babbage devised a way to mechanize this process, and he named it the Difference Engine. It could tabulate any polynomial function and provide a digital method for approximating the solution to differential equations.

How did it work? The Difference Engine used vertical shafts with disks that could be turned to any numeral. These were attached to cogs that could be cranked in order to add that numeral to (or subtract it from) a disk on an adjacent shaft. The contraption could even “store” the interim results on another shaft. The main complexity was how to “carry” or “borrow” when necessary, as we do with pencils when we calculate 36 + 19 or 42 – 17. Drawing on Pascal’s devices, Babbage came up with a few ingenious contrivances that allowed the cogs and shafts to handle the calculation.

The machine was, in concept, a true marvel. Babbage even figured out a way to get it to create a table of prime numbers up to 10 million. The British government was impressed, at least initially. In 1823 it gave him seed money of £1,700 and would eventually sink more than £17,000, twice the cost of a warship, into the device during the decade Babbage spent trying to build it. But the project ran into two problems. First, Babbage and his hired engineer did not quite have the skills to get the device working. Second, he began dreaming up

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something better.

Babbage’s new idea, which he conceived in 1834, was a general-purpose computer that could carry out a variety of different operations based on programming instructions given to it. It could perform one task, then be made to switch and perform another. It could even tell itself to switch tasks—or alter its “pattern of action,” as Babbage explained—based on its own interim calculations. Babbage named this proposed machine the Analytical Engine. He was one hundred years ahead of his time.

The Analytical Engine was the product of what Ada Lovelace, in her essay on imagination, had called “the Combining Faculty.” Babbage had combined innovations that had cropped up in other fields, a trick of many great inventors. He had originally used a metal drum that was studded with spikes to control how the shafts would turn. But then he studied, as Ada had, the automated loom invented in 1801 by a Frenchman named Joseph-Marie Jacquard, which transformed the silk-weaving industry. Looms create a pattern by using hooks to lift selected warp threads, and then a rod pushes a woof thread underneath. Jacquard invented a method of using cards with holes punched in them to control this process. The holes determined which hooks and rods would be activated for each pass of the weave, thus automating the creation of intricate patterns. Each time the shuttle was thrown to create a new pass of the thread, a new punch card would come into play.

On June 30, 1836, Babbage made an entry into what he called his “Scribbling Books” that would represent a milestone in the prehistory of computers: “Suggested Jacquard’s loom as a substitute for the drums.”30 Using punch cards rather than steel drums meant that an unlimited number of instructions could be input. In addition, the sequence of tasks could be modified, thus making it easier to devise a general-purpose machine that was versatile and reprogrammable.

Babbage bought a portrait of Jacquard and began to display it at his salons. It showed the inventor sitting in an armchair, a loom in the background, holding a pair of calipers over rectangular punch cards. Babbage amused his guests by asking them to guess what it was. Most thought it a superb engraving. He would then reveal that it was actually a finely woven silk tapestry, with twenty-four thousand rows of threads, each controlled by a different punch card. When Prince Albert, the husband of Queen Victoria, came to one of Babbage’s salons, he asked Babbage why he found the tapestry so interesting. Babbage replied, “It will greatly assist in explaining the nature of my calculating machine, the Analytical Engine.”31

Few people, however, saw the beauty of Babbage’s proposed new machine, and the British government had no inclination to fund it. Try as he might, Babbage could generate little notice in either the popular press or scientific journals.

But he did find one believer. Ada Lovelace fully appreciated the concept of a general- purpose machine. More important, she envisioned an attribute that might make it truly amazing: it could potentially process not only numbers but any symbolic notations, including musical and artistic ones. She saw the poetry in such an idea, and she set out to encourage others to see it as well.

She barraged Babbage with letters, some of which verged on cheeky, even though he was twenty-four years her senior. In one, she described the solitaire game using twenty-six marbles, where the goal is to execute jumps so that only one marble remains. She had mastered it but was trying to derive a “mathematical formula . . . on which the solution depends, and which can be put into symbolic language.” Then she asked, “Am I too imaginative for you? I think not.”32

Her goal was to work with Babbage as his publicist and partner in trying to get support to build the Analytical Engine. “I am very anxious to talk to you,” she wrote in early 1841. “I will give you a hint on what. It strikes me that at some future time . . . my head may be made

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by you subservient to some of your purposes and plans. If so, if ever I could be worthy or capable of being used by you, my head will be yours.”33

A year later, a tailor-made opportunity presented itself.

LADY LOVELACE’S NOTES In his quest to find support for his Analytical Engine, Babbage had accepted an invitation to address the Congress of Italian Scientists in Turin. Taking notes was a young military engineer, Captain Luigi Menabrea, who would later serve as prime minister of Italy. With Babbage’s help, Menabrea published a detailed description of the machine, in French, in October 1842.

One of Ada’s friends suggested that she produce a translation of Menabrea’s piece for Scientific Memoirs, a periodical devoted to scientific papers. This was her opportunity to serve Babbage and show her talents. When she finished, she informed Babbage, who was pleased but also somewhat surprised. “I asked why she had not herself written an original paper on a subject with which she was so intimately acquainted,” Babbage said.34 She replied that the thought had not occurred to her. Back then, women generally did not publish scientific papers.

Babbage suggested that she add some notes to Menabrea’s memoir, a project that she embraced with enthusiasm. She began working on a section she called “Notes by the Translator” that ended up totaling 19,136 words, more than twice the length of Menabrea’s original article. Signed “A.A.L.,” for Augusta Ada Lovelace, her “Notes” became more famous than the article and were destined to make her an iconic figure in the history of computing.35

As she worked on the notes at her country estate in Surrey in the summer of 1843, she and Babbage exchanged scores of letters, and in the fall they had numerous meetings after she moved back to her London home. A minor academic specialty and gender-charged debate has grown up around the issue of how much of the thinking was hers rather than his. In his memoirs, Babbage gives her much of the credit: “We discussed together the various illustrations that might be introduced: I suggested several but the selection was entirely her own. So also was the algebraic working out of the different problems, except, indeed, that relating to the numbers of Bernoulli, which I had offered to do to save Lady Lovelace the trouble. This she sent back to me for an amendment, having detected a grave mistake which I had made in the process.”36

In her “Notes,” Ada explored four concepts that would have historical resonance a century later when the computer was finally born. The first was that of a general-purpose machine, one that could not only perform a preset task but could be programmed and reprogrammed to do a limitless and changeable array of tasks. In other words, she envisioned the modern computer. This concept was at the core of her “Note A,” which emphasized the distinction between Babbage’s original Difference Engine and his proposed new Analytical Engine. “The particular function whose integral the Difference Engine was constructed to tabulate is Δ7ux = 0,” she began, explaining that its purpose was the computation of nautical tables. “The Analytical Engine, on the contrary, is not merely adapted for tabulating the results of one particular function and of no other, but for developing and tabulating any function whatever.”

This was done, she wrote, by “the introduction into it of the principle which Jacquard devised for regulating, by means of punched cards, the most complicated patterns in the fabrication of brocaded stuffs.” Even more than Babbage, Ada realized the significance of this. It meant that the machine could be like the type of computer we now take for granted: one that does not merely do a specific arithmetic task but can be a general-purpose machine. She explained:

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The bounds of arithmetic were outstepped the moment the idea of applying cards had occurred. The Analytical Engine does not occupy common ground with mere “calculating machines.” It holds a position wholly its own. In enabling a mechanism to combine together general symbols, in successions of unlimited variety and extent, a uniting link is established between the operations of matter and the abstract mental processes.37

Those sentences are somewhat clotted, but they are worth reading carefully. They describe the essence of modern computers. And Ada enlivened the concept with poetic flourishes. “The Analytical Engine weaves algebraical patterns just as the Jacquard loom weaves flowers and leaves,” she wrote. When Babbage read “Note A,” he was thrilled and made no changes. “Pray do not alter it,” he said.38

Ada’s second noteworthy concept sprang from this description of a general-purpose machine. Its operations, she realized, did not need to be limited to math and numbers. Drawing on De Morgan’s extension of algebra into a formal logic, she noted that a machine such as the Analytical Engine could store, manipulate, process, and act upon anything that could be expressed in symbols: words and logic and music and anything else we might use symbols to convey.

To explain this idea, she carefully defined what a computer operation was: “It may be desirable to explain that by the word ‘operation,’ we mean any process which alters the mutual relation of two or more things, be this relation of what kind it may.” A computer operation, she noted, could alter the relationship not just between numbers but between any symbols that were logically related. “It might act upon other things besides number, were objects found whose mutual fundamental relations could be expressed by those of the abstract science of operations.” The Analytical Engine could, in theory, even perform operations on musical notations: “Supposing, for instance, that the fundamental relations of pitched sounds in the science of harmony and of musical composition were susceptible of such expression and adaptations, the engine might compose elaborate and scientific pieces of music of any degree of complexity.” It was the ultimate Ada-like “poetical science” concept: an elaborate and scientific piece of music composed by a machine! Her father would have shuddered.

This insight would become the core concept of the digital age: any piece of content, data, or information—music, text, pictures, numbers, symbols, sounds, video—could be expressed in digital form and manipulated by machines. Even Babbage failed to see this fully; he focused on numbers. But Ada realized that the digits on the cogs could represent things other than mathematical quantities. Thus did she make the conceptual leap from machines that were mere calculators to ones that we now call computers. Doron Swade, a computer historian who specializes in studying Babbage’s engines, has declared this one of Ada’s historic legacies. “If we are looking and sifting history for that transition, then that transition was made explicitly by Ada in that 1843 paper,” he said.39

Ada’s third contribution, in her final “Note G,” was to figure out in step-by-step detail the workings of what we now call a computer program or algorithm. The example she used was a program to compute Bernoulli numbers,3 an exceedingly complex infinite series that in various guises plays a role in number theory.

To show how the Analytical Engine could generate Bernoulli numbers, Ada described a sequence of operations and then made a chart showing how each would be coded into the machine. Along the way, she helped to devise the concepts of subroutines (a sequence of instructions that performs a specific task, such as computing a cosine or calculating compound interest, and can be dropped into larger programs as needed) and a recursive loop (a sequence of instructions that repeats itself).4 These were made possible by the punch-card mechanism. Seventy-five cards were needed to generate each number, she explained, and then the process became iterative as that number was fed back into the process to generate the next one. “It will be obvious that the very same seventy-five variable cards may be repeated for the computation of every succeeding number,” she wrote. She envisioned a library of commonly used subroutines, something that her intellectual heirs, including women such as

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Grace Hopper at Harvard and Kay McNulty and Jean Jennings at the University of Pennsylvania, would create a century later. In addition, because Babbage’s engine made it possible to jump back and forth within the sequence of instruction cards based on the interim results it had calculated, it laid the foundation for what we now call conditional branching, changing to a different path of instructions if certain conditions are met.

Babbage helped Ada with the Bernoulli calculations, but the letters show her deeply immersed in the details. “I am doggedly attacking and sifting to the very bottom all the ways of deducing the Bernoulli numbers,” she wrote in July, just weeks before her translation and notes were due at the printers. “I am in much dismay at having gotten so amazing a quagmire and botheration with these Numbers that I cannot possibly get the thing done today. . . . I am in a charming state of confusion.”40

When it got worked out, she added a contribution that was primarily her own: a table and diagram showing exactly how the algorithm would be fed into the computer, step by step, including two recursive loops. It was a numbered list of coding instructions that included destination registers, operations, and commentary—something that would be familiar to any C++ coder today. “I have worked incessantly and most successfully all day,” she wrote Babbage. “You will admire the Table and Diagram extremely. They have been made out with extreme care.” From all of the letters it is clear that she did the table herself; the only help came from her husband, who did not understand the math but was willing to methodically trace in ink what she had done in pencil. “Lord L is at this moment kindly inking it all over for me,” she wrote Babbage. “I had to do it in pencil.”41

It was mainly on the basis of this diagram, which accompanied the complex processes for generating Bernoulli numbers, that Ada has been accorded by her fans the accolade of “the world’s first computer programmer.” That is a bit hard to defend. Babbage had already devised, at least in theory, more than twenty explanations of processes that the machine might eventually perform. But none of these was published, and there was no clear description of the way to sequence the operations. Therefore, it is fair to say that the algorithm and detailed programming description for the generation of Bernoulli numbers was the first computer program ever to be published. And the initials at the end were those of Ada Lovelace.

There was one other significant concept that she introduced in her “Notes,” which harked back to the Frankenstein story produced by Mary Shelley after that weekend with Lord Byron. It raised what is still the most fascinating metaphysical topic involving computers, that of artificial intelligence: Can machines think?