Analytical Engine

The Analytical Engine (English for analytical machine ) is the design of a mechanical calculating machine for general applications. It comes from the British professor of mathematics Charles Babbage (1791-1871) and represents an important step in the history of the computer


Babbage began in 1822 with the construction of his Difference Engine, a mechanical calculating machine, which was designed specifically for the solution of polynomial functions. When it became clear that a much more general construction would be possible, he designed an analytical engine, the description he published in 1837. He continued the work on the draft continued until the end of his life. It is now generally accepted that the design was correct and that the Analytical Engine would have worked. Comparable computer for general applications have been realized until a century later.

The Analytical Engine was to be powered by a steam engine and would have been about 30 meters long and 10 meters wide. The input (commands and data) should be via punched cards, a method that was used at that time the control of mechanical looms. For the output of a printer, a Kurvenplotter and a bell were planned ( as a signal to the operator ). The machine should also be able to punch numbers into punched cards or optional metal plates. She used decimal floating-point arithmetic and it was memory provided for 1000 words 50 decimal places (Equivalent to about 20.7 kB). The arithmetic unit ( " mill " called ) should be able to perform the four basic arithmetic operations.

The proposed language was similar to the structured assembler languages ​​used today. Loops and conditional branches would have been possible, so that the first universal programmable ( Turing powerful ) system would be created. Three different types of punch cards were provided: one for load and store operations to transfer the arithmetic operation, a numerical constants and numbers from the memory into the arithmetic unit and back again. Probably three separate punch card readers for the three types of cards would have been used.


1837 Babbage published the first descriptions of his Analytical Engine. Due to financial and technical problems but few components were actually built.

1842 wrote the Italian mathematician Luigi Federico Menabrea, who had taken the traveling Babbage in Italy, a description of the Analytical Engine in French. Ada Lovelace translated them into English. Following a request from Babbage, why could she not written a separate treatise, her translation of such detail that it took three times the length of the original article. Because she has also created a written plan for calculating Bernoulli numbers with the machine, it is also called " first programmer " in history.

1878 recommended that a committee of the British Association for the Advancement of Science, not to build analytical engine.

1910 reported Babbage's son, Henry P. Babbage, that part of the computing unit and the printer is built and this would have been used to calculate an (incorrect ) list of multiples of pi. This was just a small part of the whole engine, not programmable and without memory.

Then came the machine whose design plans shall be deemed functional, into oblivion.

1941, the Zuse Z3 by Konrad Zuse, the first universal programmable computer, which was actually built and working. And only in 1960 reached the computer from Babbage envisaged for the Analytical Engine arithmetic precision ( 50 decimal places are about 166 bits or 20 bytes). Howard Hathaway Aiken, the electric calculating machine Mark I built 1943-44, was influenced by the design of the Analytical Engine.

From Babbage's autobiography: