Ada Lovelace, !Notes" to a !Sketch of the Analytical Engine Invented by Charles Babbage,by L.F. Menabrea," in Scientific Memoirs (London, 1843), vol. 3.

Ada LovelaceFirst Computer Programmer

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What is the difference between a calculating machine and a computer?

Charles Babbage designed two kinds of mechanicalcomputational machines: a !difference engine,# or calculatingmachine; and an !analytical engine,# which was far more. In1840, Babbage presented his design for the !analytical engine# toa group of mathematical engineers in Turin, Italy. One of them,Luigi Menabrea, who would later become Prime Minister ofItaly, published an account of Babbage$s design in Geneva. WithBabbage$s encouragement, the daughter of Lord Byron, AugustaAda King, Countess of Lovelace, translated Menabrea$s articleinto English and added her own substantive commentary.Lovelace$s notes went considerably beyond what Babbage andMenabrea had written. Her lengthy appended notes amount to40 pages of very dense text compared with only 24 pages,lightly spaced, for Menabrea$s article. Lovelace explained howBabbage$s !analytical engine,# if constructed, would amount to aprogrammable computer rather than merely a calculator. Itwould take input from punch cards, and store variables for use indiverse sequential operations. These 19th century mechanicaloperations are functionally equivalent to the conditionalbranching, looping, and parallel processing operations of earlyelectronic computers. Although she specified how Babbage$sengine could generate a Bernoulli series of numbers, Lovelaceargued for the wider potential of the engine to produceanalytical results beyond the realm of mathematics.

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Ada Lovelace: First Computer Programmer

Kerry Magruder and Brent Purkaple