Difference Engine


Also found in: Wikipedia.

Difference Engine

(computer, history)
Charles Babbage's design for the first automatic mechanical calculator. The Difference Engine was a special purpose device intended for the production of mathematical tables. Babbage started work on the Difference Engine in 1823 with funding from the British Government. Only one-seventh of the complete engine, about 2000 parts, was built in 1832 by Babbage's engineer, Joseph Clement. This was demonstrated successfully by Babbage and still works perfectly. The engine was never completed and most of the 12,000 parts manufactured were later melted for scrap.

It was left to Georg and Edvard Schuetz to construct the first working devices to the same design which were successful in limited applications. The Difference Engine No. 2 was finally completed in 1991 at the Science Museum, London, UK and is on display there.

The engine used gears to compute cumulative sums in a series of registers: r[i] := r[i] + r[i+1]. However, the addition had the side effect of zeroing r[i+1]. Babbage overcame this by simultaneously copying r[i+1] to a temporary register during the addition and then copying it back to r[i+1] at the end of each cycle (each turn of a handle).

Difference Engine at the Science Museum.

Difference Engine

An early calculator designed by Charles Babbage and subsidized by the British government. Employing wheels and rods, which others had experimented with earlier, the project was started in 1821 but failed its test in 1833. Babbage then turned his attention to the Analytical Engine and completely abandoned the Difference Engine by 1842. Although never completed, it did improve the precision of Britain's machine-tool industry. In 1991, the National Museum of Science and Technology built a working model of the Difference Engine.

In 1879, Babbage's son reassembled a section of the Difference Engine from parts, and in 1995, Christie's auction in London auctioned off that section to the Power House Museum in Sydney for USD $282,000. The other known sections are owned by Harvard and Cambridge Universities. See Analytical Engine.


The Difference Engine
This impression from a woodcut was printed in 1853 showing a portion of the Difference Engine that was built in 1833. Babbage later turned his attention to the Analytical Engine. It, too, was never finished. (Image courtesy of Charles Babbage Institute, University of Minnesota, www.cbi.umn.edu)
References in periodicals archive ?
Using Difference Engine, a next generation learning environment and tools, Learning Objects collaborates with institutions and other education providers to deliver competency-based, personalized, and adaptive learning at scale.
It's the biggest collection of computer artefacts anywhere in the world, and it's not only a brilliant account of the progress of computing technology from Babbage's difference engine to the smartphone.
The Difference Engine received support from the likes of One North East, Sunderland and Middlesbrough councils, and launched with the ambition to propel ideas from the North East and further afield into fully fledged businesses.
Incorporating Learning Objects Difference Engine, Elsevier built ExamPrep on an adaptive assessment algorithm that takes into account learner mastery and established learning science.
Incorporating Learning Objects' Difference Engine, Elsevier built ExamPrep on an adaptive assessment algorithm that takes into account learner mastery and established learning science.
The young Ada was tutored in maths and |after meeting Charles Babbage in 1833 at a party became fascinated by his analytical Difference Engine, forerunner of the modern electronic computer.
Cambridge University Press is to publish a book which tells the story of computer science from Charles Babbage and the Difference Engine to Strong Al and beyond, including sections on the fundamentals of computer science, computational thinking, the origins of PCs, smart phones and games, and key issues surrounding online security, hacking and cyber-warfare.
She was Lord Byron's daughter and worked alongside Charles Babbage preparing the punched cards for his difference engine.
Not even mechanical computers like Charles Babbage's Difference Engine (1849) or Konrad Zuse's electromechanical Z3 (1941).
It holds more than 300,000 items including 700 human remains, Stephenson's Rocket, Puffing Billy and a working version of Charles Babbage's Difference Engine (considered by many to be the first computer).
One of the most influential science fiction writers of his generation, William Gibson's fiction includes 10 novels (Neuromancer [1984], Pattern Recognition (2003), The Difference Engine (1990), Zero History [ [EXCELLENT] Nov/Dec 2010]) and a book of short fiction, Burning Chrome (1986).
Search optimisation solutions provider ASEOPROtools announced on Tuesday the release of its SEO Difference Engine, a professional-grade toolset designed for use by the general business public.

Full browser ?