Who is Ada Lovelace?

Charles Babbage's first attempt at a mechanical computing device was the difference engine, a special-purpose calculator designed to tabulate logarithmstrigonometric functions by evaluating approximate polynomials. As this project faltered for personal and political reasons, he realized that a much more general design was possible and started work designing the analytical engine. and

The analytical engine was to be powered by a steam engine and would have been over 30 metres long and 10 metres wide. The input (programs and data) was to be provided to the machine via punched cards, a method being used at the time to direct mechanical looms. For output, the machine would have a printer, a curve plotter and a bell. The machine would also be able to punch numbers onto cards to be read in later. It employed ordinary base-10 fixed-point arithmetic.

There was to be a store (i.e., a memory) capable of holding 1,000 numbers of 50 digits each. An arithmetical unit (the "mill") would be able to perform all four arithmetic operations, plus comparisons and optionally square roots. Initially it was conceived as a difference engine curved back upon itself, in a generally circular layout, with the long store exiting off to one side. (Later drawings depict a regularized grid layout.) Like the central processing unit (CPU) in a modern computer, the mill would rely upon its own internal procedures, to be stored in the form of pegs inserted into rotating drums called "barrels," in order to carry out some of the more complex instructions the user's program might specify.^[4] (See microcode for the modern equivalent.)

The programming language to be employed by users was akin to modern day assembly languages. Loops and conditional branching were possible and so the language as conceived would have been Turing-complete long before Alan Turing's concept. Three different types of punch cards were used: one for arithmetical operations, one for numerical constants, and one for load and store operations, transferring numbers from the store to the arithmetical unit or back. There were three separate readers for the three types of cards.

In 1842, the Italian mathematician Luigi Menabrea, whom Babbage had met while travelling in Italy, wrote a description of the engine in French. In 1843, the description was translated into English and extensively annotated by Ada King, Countess of Lovelace, who had become interested in the engine ten years earlier. In recognition of her additions to Menabrea's paper, which included a way to calculate Bernoulli numbers using the machine, she has been described as the first computer programmer. The modern computer programming language Ada is named in her honour.

via wikipedia..