Cobra Effect · Computing and information
The notes that imagined a computer
How Ada Lovelace's notes on an unbuilt machine imagined what computers could do.
7 cards, read aloud in 2:36, with a test and sources.
In 1833, a seventeen year old named Ada Byron met the inventor Charles Babbage.
She was the daughter of the poet Lord Byron, and had been schooled in mathematics. Babbage was designing calculating machines built from brass gears. His later design, the Analytical Engine, was to be given its instructions on punched cards.
In 1842, an Italian engineer published an article about the Analytical Engine.
Luigi Menabrea, a military engineer from Turin, wrote it in French. Ada, by then Countess of Lovelace, translated it into English. Then she added notes of her own.
Her notes ended up far longer than the article itself.
Of the sixty six pages published in 1843, forty one were her notes. They were signed only with her initials. They explained in detail how the machine could be set up to carry out long calculations.
In her final note, she set out a step by step plan for calculating a series of numbers.
The numbers were the Bernoulli numbers, which appear in many areas of mathematics. Her table showed each operation the engine would perform, including steps that repeat. It is often called the first computer program, though historians debate that title. Babbage had written programs for the engine earlier, but never published them.
She saw that the machine could do more than arithmetic.
It could work with any symbols whose relationships could be written down. It might even compose music, she suggested, if musical relationships could be expressed that way. She wrote that it wove patterns in algebra, just as a loom wove flowers and leaves.
But she also set a limit on what it could do.
The engine, she wrote, could not originate anything. It could only do whatever people knew how to order it to perform. The Analytical Engine was never built. Only a trial piece existed when Babbage died, in 1871.
So when a new machine appears, ask what it could do beyond its first purpose.
Babbage’s engine was designed for calculation. Lovelace imagined it handling symbols, patterns and even music. Seeing the general idea behind a particular machine let her look a century ahead.
Sources
- Sketch of the Analytical Engine, with notes by the translator, Menabrea and Lovelace, 1843, via Fourmilab. The full text of the article and Lovelace’s notes.
- Ada Lovelace and the Analytical Engine, Bodleian Libraries. The notes, the table, and her letters with Babbage.
- What Did Ada Lovelace’s Program Actually Do?, Two-Bit History. A walk through the steps in her final note.
Nearby ideas
- The question no machine can answer. How Alan Turing imagined the computer, and proved some questions have no answer.
- The man who measured information. How Claude Shannon turned information into something that could be measured in bits.
- The codebreakers who read Enigma. How Polish mathematicians and Bletchley Park broke Germany's Enigma machine.
- The codes that fix their own mistakes. How a frustrated mathematician invented codes that find and fix their own errors.
- The tiny switch that replaced the valve. How a slab of germanium at Bell Labs gave rise to every modern chip.