Who Was Ada Lovelace?

Who were Ada Lovelace's parents, and how was she educated?

Ada Lovelace was born Augusta Ada Byron on December 10, 1815, in Piccadilly, London.^[1][3] She was the only legitimate child of the poet Lord Byron and Annabella Milbanke.^[1] Her parents had married on January 2, 1815, and separated on January 16, 1816, about a month after she was born.^[3] Byron went abroad in April 1816, and Ada never saw him again; he died in Greece when she was eight.^[3]

Her mother, whom Byron called his "Princess of Parallelograms", had mathematical training and insisted that Ada, who was taught privately, study mathematics too, an unusual education for a woman.^[1] According to the MacTutor archive, she also tried to ensure that Ada would not become a poet like her father.^[3]

Lovelace had no access to formal schooling or a university education.^[5] Her tutors included the scientific writer Mary Somerville and the mathematician Augustus De Morgan.^[4] She began advanced study in mathematics with De Morgan in 1841, and the Clay Mathematics Institute says their correspondence course shows her developing into a gifted mathematician.^[3][5]

She married William King in 1835, and when he became the Earl of Lovelace in 1838 she became Countess of Lovelace.^[3][4] The couple had three children.^[3]

How did she meet Charles Babbage, and what was the Analytical Engine?

Lovelace met Charles Babbage at a party in 1833, when she was seventeen.^[1][3] Two weeks later she and her mother visited his London studio, where the Difference Engine was on display.^[3] She was entranced when Babbage demonstrated a small working section of the engine to her.^[1] Sources differ on how they met: the Science Museum Group says Mary Somerville introduced them, while MacTutor dates Lovelace's first meeting with Somerville to 1834, the year after she met Babbage.^[4][3]

Babbage began his first Difference Engine in 1821, and machines of this kind were strictly calculators.^[6] In 1834 he conceived a more ambitious design, later called the Analytical Engine: a general-purpose, programmable computing machine.^[6] It was to be programmed with punched cards, an idea borrowed from the Jacquard loom used to weave patterned cloth, and it had a "Store" to hold numbers and a separate "Mill" to do the arithmetic.^[6] It was never built.^[2]

What did Ada Lovelace write in her 1843 Notes?

In 1840 Babbage lectured in Turin, and Luigi Menabrea, who was in the audience, published the first account of the engine, in French, in October 1842.^[2] Charles Wheatstone, a scientific friend, asked her to translate it, and Babbage suggested that she add appendices.^[2] The result was published in Taylor's Scientific Memoirs in August 1843, signed only with her initials, A.A.L.; of its sixty-six pages, forty-one were her own Notes.^[2]

The final appendix, Note G, showed how the engine would calculate the Bernoulli numbers, a sequence that turns up in many parts of mathematics.^[2] These numbers suit machine calculation because each one can be found from the ones before it.^[2] Lovelace explained how the quantities in the calculation would be fetched from the Store, worked on in the Mill and moved back again according to the instructions on the cards, and she set out the whole process in a large table.^[2]

Was Note G really the first computer program?

The Computer History Museum says her Notes contained the first published description of a step-by-step sequence of operations for solving certain mathematical problems, and she is often called "the first programmer".^[1] Her table is often described as the first computer program.^[2]

Christopher Hollings, Ursula Martin and Adrian Rice, who studied her manuscripts at Oxford's Bodleian Library, add a caution.^[2] Strictly speaking, they write, the table is what computer scientists now call an "execution trace"; the program itself would have been the deck of punched cards that drove the machine.^[2] Babbage's designs were unclear about how the cards would be handled, so the exact program is hard to reconstruct.^[2]

The Computer History Museum also notes that her collaboration with Babbage was close and that biographers debate the extent and originality of her contribution.^[1] In his 1864 memoir, Passages from the Life of a Philosopher, as quoted by MacTutor, Babbage wrote that the choice of illustrations was entirely her own, as was the algebra, except for the Bernoulli numbers, which he had offered to work out.^[3] He added that she sent that work back to him after detecting a serious mistake he had made.^[3]

Why is she called a visionary?

Lovelace saw that the engine might work on things other than numbers, as long as those things followed mathematical rules.^[2] If the relationships between musical pitches could be expressed that way, she wrote, the engine "might compose elaborate and scientific pieces of music of any degree of complexity or extent".^[1][2] The Computer History Museum describes this idea as the fundamental shift from calculation to computation and says that here she appears to have seen further than Babbage.^[1]

She also argued that the engine could not have original ideas: it had "no pretensions whatever to originate anything".^[2] Alan Turing later challenged this view in his paper "Computing machinery and intelligence", calling it "Lady Lovelace's objection".^[2]

How did Ada Lovelace die, and how is she remembered?

In the last months of her life Lovelace was in great pain from uterine cancer.^[7] She died on November 27, 1852, in Marylebone, London.^[3] The Science Museum Group and the Clay Mathematics Institute give her age at death as 36, while the MacTutor biography says 37.^[4][5][3] By this article's own count from her birth and death dates, she was 36.^[3]

Her contribution went largely unnoticed by the scientific community of the mid-19th century and was not fully appreciated until electronic computing arrived a century later.^[4] Ada Lovelace Day, founded in 2009 by Suw Charman-Anderson, aims to raise the profile of women in science, technology, engineering and mathematics.^[4] The Ada programming language, created to meet requirements drawn up by the US armed forces, was named in her honor by members of the government team.^[8]