CSE 301 History of Computing Charles Babbage. 1800

CSE 301History of Computing

Charles Babbage

1800

The Table-Making IndustryFrance in 1790midst of French Revolutionstorming of Bastille was in 1789change from monarchy to republicled by Napoleon Bonaparte

Gaspard De PronyHired to calculate the Tables du Cadastretables to help reassess taxes forused the principles of mass production

Whats a nautical almanac?Describes the positions and movements of celestial bodiessun, moon, planets, 57 stars

Using a sextant and the Nautical Almanac, one can determine where ones ship is

Requires lots of calculations

Enter Charles Babbage

Charles Babbage1792-1871The (grand)father of computingMathematician, industrialist, philosopher, politicianWrote On the Economy of Manufactures (1832)EccentricLoved fire, hated musicLittle known when he diedBrain dissected years later

Babbage and Nautical TablesWorked on table-making project for the Nautical Almanacfor astronomers & navigators

How did he like the work?found the work tedious & error-pronekey step in calculations: the method of differences

What was his proposal?a machine to calculate & print tables

Difference EngineMachine proposed by Babbage1822 demonstrated the concept was feasible and could be built with enough funds1823 secured 1500 to build1833 a prototype was built in 18331842 Babbage loses government fundingafter 17000 totalBabbage did not live to see a complete functioning Difference Engine

Babbage Difference EnginePhoto of the 1832 Fragment of a Difference Engine fragment made by H.P.Babbage from parts of Difference Engine No.1

A Swedish Difference Engine1853 Father and son Georg and Edvard Scheutz of Sweden create the first complete difference enginealso the first calculator in history to be able to print out its results.

Why did Babbages Difference Engine fail?The engineering was more difficult than the conceptualizationTwo tasks were necessary:design the Difference Enginedevelop the technology to manufacture itOther reasons:Babbage was a perfectionistBabbage lost interestmoney, Babbages degrading reputation, heartbreak

Babbage Difference EnginePhoto of Babbage Difference Engine No. 2constructed in 1991

On display at Londons Science Museum

Analytical EngineDesigned around 1834 to 1836to be a universal machinecapable of any mathematical computationembodies many elements of todays digital computerKey ideas:a control unitmill performed arithmetic operations (like an ALU)store stored numbers (like registers)store had 1000 registers of 50 digits eachIncorporated using punched cards for inputidea came from Jacquard loomNever built by Babbage due to lack of funds and his eventual death in 1871

Analytical EngineDesign included conditional branching (decision making capabilities)based on whether the difference between two values was positive or negative.Example:Repeat calculation if 423 < 511.This means check if 423 511 < 0 (negative) 00000 00423 00000 00511 999999 99912Engine Instructions stored on punch cards strung together with loops of string to form a continuous chain

Analytical EnginePortion of the mill of the Analytical Engine with printing mechanism, under construction at the time of Babbages death.Analytic Engine completed by Babbages son, Henrylithographby Babbage

Going to London? Go to the Science MuseumPortion of Difference Engine (1832) Scheutz Difference Engine (1843)Experimental models and moulds from Charles Babbages work on calculating machines (1870)Portion of Analytical Engine, under construction at the time of Babbages death (1871)Difference Engine No. 2, trial piece made in the Science Museum Workshop (1989) Difference Engine No. 2, built by the Science Museum (1991)

Ada Augusta Byron,Countess Lovelace1815-1852Daughter of poet Lord ByronMathematician who assisted Babbagemuch admired by Babbageshe understood the significance of his work, which others did notTranslated Menabreas Sketch of the Analytical Engine to English (described Babbages machine)quadrupled its length by adding lengthy notes and detailed mathematical explanationsfact checked Babbages work & programs

Ada the first programmer?Ada provided detailed instructions for how the analytical engine would workSome refer to as the worlds first programmerSome historians dispute this moniker, including our authorssay most of the technical content & all of the programs were BabbagesAda programming language named for herWeaved coded instructions on punched cardsbased on a language that was compatible with the Analytical Engine

Carrying on the VisionOthers made their own analytical engines, updating Charles Babbages designHenry P. Babbage (son) created an assemblage of part of the Engine in 1910 (the mill and the printer)Percy Ludgate, accountant (1883-1922)replaced punched cards with perforated paper rollelectric motor used to drive main cyclinderTorres y Quevedo used electromagnetic relays to create an elementary analytical engine exhibited in Paris in 1914.

Referenceshttp://tergestesoft.com/~eddysworld/babbage.htm

**He Loved Fire-he once was baked in an oven at 265F for 'five or six minutes without any great discomfort-on another occasion was lowered into Mount Vesuvius to view molten lava

He hated music-Neighbors hired musicians to play outside his windows-When Babbage went out, children followed and cursed him -He hated street musicians and pushed for the enforcement of Babbages Act (1864) to silence them, causing much ridicule.

Brain Dissected-In 1908, after being preserved for 37 years in alcohol, Babbage's brain was dissected by Sir Victor Horsley of the Royal Society

While alive, he was belittled & marginalized by the British Press*****The example here shows that if we subtract, as we continue to borrow, some mechanism in the machine would hook to the next digit to the left, and so on, until the leftmost subtraction would cause a borrow causing an external switch to flip and make the string of punch cards advance or retract a certain set number of positions.*The example here shows that if we subtract, as we continue to borrow, some mechanism in the machine would hook to the next digit to the left, and so on, until the leftmost subtraction would cause a borrow causing an external switch to flip and make the string of punch cards advance or retract a certain set number of positions.*Some historians argue that Ada didnt write the technical formulas and diagrams; these were Babbages doing. However, she did understand his machine very well and described it in a much more visual exciting manner than Babbage could ever accomplish.*