# Analytical engine

the Analytical engine, which represents an important step in the history of the computers, is the draft of a mechanical calculating machine for general uses of Charles Babbage, a British professor of mathematics. It became 1837 for the first timedescribed, Babbage continued the work on the draft however up to the end of its life (1871). Under financial and technical problems the Analytical engine was never built. It is meanwhile however generally recognized that the draft correctlyit was and that the equipment would have functioned. Comparable computers for general applications were really designed only 100 years later.

Babbage began with the construction of its Difference engine, a mechanical computer, which was particularly for the solution of polynomialer functions conceived.When it it became clear that a much more general building method would be possible, it began with the work on the Analytical engine.

This should be propelled by a steam engine and over 30 meters long and would have been 10 meters wide. The input(Instructions and data) a method by punch cards, which served the controlling of mechanical looms in the time at that time , should be made. For the expenditure were planned a printer, a curve plotter and a bell. In addition the machine should numbers in punch cards or alternativelyMetal plates to punch can. It used decimal floating point arithmetic and it was memory for 1000 words to 50 decimal places intended. The arithmetic and logic unit (“mill” mentioned) should be able to accomplish the four basic operations of arithmetic.

The intended programming language was similar to the assembler languages used today. Loops and conditioned bypasses were possible. Three different kinds of punch cards were used: one for arithmetic operations, one for numeric constants and one for loading and memory operations, over numbers from the memory into the arithmetic and logic unit and again back tootransfer. There were probably three separate punch card readers for the three types of card.

1842 wrote the Italian mathematician Menabrea, which had met the traveler Babbage in Italy, a description of the Analytical engines on French, those from lady Ada Augusta, Countess OF Lovelacetranslated into English and (after an inquiry of Babbage, why she would not have written her own paper it was commentated in detail). Their interest in the engine had been aroused already 10 years in former times. Their notes to Menabreas description have itlater the title “first Programmiererin” brought in.

1878 recommended a committee to that British Association for the Advancement OF Science not to build the Analytical engine.

1910 reported Babbages son, Henry P. Babbage that a part of the arithmetic and logic unit and the printer builtand for it used would be to calculate a list of multiples of pi (incorrect ). This was only a small part of the whole engines, not programmable and without memory.

Afterwards the machine came into oblivion. The plans for their structure apply howeveras functional, and only around 1960 realized computer the computational accuracy planned of Babbage (50 decimal places are approx. 166 bits and/or. 20 byte).Howard Hathaway Aiken, which built the electrical calculating machine Havard Mark of I later, was affected by its structure.

From Babbages autobiography:

As soon as a Analytical engine exists, it becomes necessarily the science the future direction points.