The Babbage Faq

We have heard the same story for a long time. CharlesBabbage was the first person ever to be able to build something that could resemble a modern-day computer. But he was very much ahead of its time and it was not possible technically to build a computer although he had all the elements. Legend has it that he was born 50 or 60 years too early. One of his plans would have looked like this; now implemented and functional:

( http://gadgets.boingboing.net/2008/05/02/babbage-difference-e-1.html }

What in the world is Babbage's algorithm that makes him the father of the computer? Anyone has a clue? Wikipedia does not seem to have a clue either...

Babbage is remembered for his remarkable design, not an "algorithm". The absence of material about Babbage on Wikipedia (if true) reflects on Wikipedia, not Babbage. A Google search using the query string "babbage difference engine computer" on March 23, 2004, yielded 23,700 hits. Here are two of them, with excerpts, that help illuminate why Babbage is credited with so large a role in the development of the computer. -- TomStambaugh

http://www.computer.org/history/development/1822.htm

: Charles Babbage recognized that among the most common of calculating devices - the mathematical, celestial, and navigation tables - are full of errors and leading to the loss of ships. While studying at Cambridge University he suggests that it ought to be possible to compute the table entries using a steam engine. This desire becomes the theme of his life and he begins to design the Difference Engine for the purposes of computing the entries in navigation and other tables. Later he applies to the British Government for assistance, and receives what may have been the first government grant for computer research - an event that is repeated a hundred years later in the US to help build the ENIAC at the University of Pennsylvania.

http://www.maxmon.com/1830ad.htm

: In 1822, Babbage proposed building a machine called the Difference Engine to automatically calculate mathematical tables. The Difference Engine was only partially completed when Babbage conceived the idea of another, more sophisticated machine called an Analytical Engine. (Some texts refer to this machine as an "Analytical Steam Engine," because Babbage intended that it would be powered by steam).
: The Analytical Engine was intended to use loops of Jacquard's punched cards to control an automatic calculator, which could make decisions based on the results of previous computations. This machine was also intended to employ several features subsequently used in modern computers, including sequential control, branching, and looping.
: (...)
: Babbage worked on his Analytical Engine from around 1830 until he died, but sadly it was never completed. It is often said that Babbage was a hundred years ahead of his time and that the technology of the day was inadequate for the task. Refuting this is the fact that, in 1834, two Swedish engineers called Georg and Edward Scheutz built a small Difference Engine based on Babbage's description. In his book, Engines of the Mind, Joel Shurkin stated:
: "One of Babbage's most serious flaws was his inability to stop tinkering. No sooner would he send a drawing to the machine shop than he would find a better way to perform the task and would order work stopped until he had finished pursuing the new line. By and large this flaw kept Babbage from ever finishing anything."
: Further supporting this theory is the fact that, in 1876, only five years after Babbage's death, an obscure inventor called George Barnard Grant exhibited a full-sized difference engine of his own devising at the Philadelphia Centennial Fair. Grant's machine was 8 feet wide, 5 feet tall, and contained over 15,000 moving parts.
: The point is that, although Babbage's Analytical Engine was intellectually far more sophisticated than his Difference Engine, constructing an Analytical Engine would not have been beyond the technology of the day.

Some folks outside of the computer profession are unaware of the relationship between a calculator and a modern computer, and may therefore not know that the need to compute ballistics tables for World War II gunners created the first generation of computers. It is nevertheless clear that Babbage's role in the history of computing is immediately accessible to anyone who bothers to do even a little bit of research.

They may also not know that the very term "computer" meant a human, and that the motivation for electronic computers was the result of experience with human "computers" who were calculating ballistics tables for the military prior to World War II. The first human computers were Alexis-Claude Clairaut (1713-1765), Joseph Jerome Lalande (1732�1807), and Reine Lepaute (1723�1788). Using a numeric algorithm invented by Clairaut, they calculated the orbit of Halley's comet, culminating in their announcement in November of 1757 that it would reach its perihelion on April 13, 1759. A French civil engineer (Gaspard de Prony) built on this to create 19 volumes of trigonometric and logarithm tables for the revolutionary French government, using about 80 human "computers" to do the arithmetic. Prony had divided the computations into a series of additions and subtractions. This laid the mathematical foundation for Babbage to build on with his Difference Engine and Analytical Engine. This material is all available at http://www.philsoc.org/2001Spring/2132transcript.html, the first hit resulting from Googling with the string "ballistics table computer human history".

In short - the need for a mechanical and then electronic calculator motivated the creation of the electronic computer. The very term "computer" was synonymous with a person who performed calculations. Babbage not only designed a working calculator, his "Analytic Engine", with its loops of punched cards programmed by Ada Lovelace (daughter of the English poet Lord Byron), presaged many of the architectural concepts still used in electronic computers.

-- TomStambaugh

Comments

Mr Babbage developed the plans for a machine which could compute logarithms mechanically. The plans have been widely reproduced, and, if I recall correctly, a replica has been built in recent years.

A table of logarithms was published in 1617. Presumably, trigonometric functions were tabulated long before that. Hence it took a long time for mechanization of calculation to come on the scene.

My understanding is that he created the first design of a machine capable of TuringComplete (TC) computations, although he never finished building it. The second TC machine was a German electro-mechanical computer actually built during WWII, roughly 60 years after Babbage's design. (See KonradZuse.) However, the known computations actually used at the time didn't take advantage of TC features. Some of Babbage's or Ada's first draft algorithms alleged did.

"The absence of material about Babbage on Wikipedia (if true) reflects on Wikipedia, not Babbage."

While it may have been true when this was written, it isn't now. http://en.wikipedia.org/wiki/Charles_Babbage and http://en.wikipedia.org/wiki/Difference_engine at least have the basics.

CategoryHistory