Augusta Ada King, Countess of Lovelace (1815-1852), was an English mathematician who became closely associated with Charles Babbage’s plans for the Analytical Engine, a proposed general-purpose mechanical computer. The daughter of the poet Lord Byron, she was tutored in mathematics from an early age and corresponded with Babbage about his machines.
In 1843 she published an English translation of an article by the Italian engineer Luigi Federico Menabrea describing the Analytical Engine. To the translation she appended a series of her own explanatory notes, labeled A through G, which together ran far longer than the original article. The notes were published under the initials “A.A.L.” and the translation is credited to “the Translator ADA AUGUSTA, COUNTESS OF LOVELACE.”
The notes go beyond mechanical description. In them Lovelace discusses how the engine could operate on symbols and quantities other than numbers, and she lays out a detailed step-by-step procedure, in Note G, for the engine to compute the Bernoulli numbers. This procedure is widely regarded as the first published example of an algorithm written specifically to be carried out by a machine.
Because the Analytical Engine was never completed, Lovelace’s program was never run on the hardware it was written for. Her notes nevertheless stand as an early and unusually clear statement of what a programmable, general-purpose computing machine could do.