The analytical engine was a mechanical computer created by English inventor and mathematician Charles Babbage in the mid-1830s. Although Babbage never built the whole machine, the analytical engine is generally considered the precursor to the modern computer. It used a punch card programing system and had a processing unit to do calculations as well as a short-term memory bank to store working data.
Babbage was a professor of mathematics at Cambridge. While working with mathematical tables in 1812, Babbage came up with the idea of a machine that could do calculations automatically. First he invented the difference engine, known today as difference engine No. 1.
The difference engine was very specialized. It was designed to work only with polynomials. When the project stalled, Babbage decided to widen his focus and create a multipurpose machine.
In 1839, he began to devote all of his scholarly thought to the development of the analytical engine. Babbage envisioned the engine as made of brass and powered by a steam engine. Data were fed into the analytical engine using punch cards. Babbage borrowed the idea for punch cards from the textile industry, where they were being used to program mechanical looms.
The engine had three different kinds of card readers for the cards that programmed the machine. One type of card inputted mathematical operations, another directed the load and save actions, and the third fed the machine numerical constants. The programming language was similar to the assembly languages used a century later.
Once data had been inputted, the analytical engine could solve equations by adding, subtracting, multiplying, and dividing as well as performing other computer-like functions. While calculating, the analytical engine was able to use what is basically scratchpad memory. It could store 1,000 numbers, each of which could be up to 50 digits long. When calculations were complete, the analytical engine could output the answers in print, punch card, or graph form. It could also create trays that could later be used to make printing plates.
Modern computer scientists recognize that Babbage was ahead of his time. All the parts of his analytical engine are echoed in modern computers. Like many visionaries, Babbage had trouble getting others to recognize his genius. A full prototype was never built because Babbage could not get funding. He did create parts of the machine, which survive in museums. It took nearly 100 years after Babbage's death in 1871 before computers were built that were comparable to the analytical engine.