A modern model of Babbage’s analytical en-
gine, built in 1992, found in the Science Mu-
The analytical engine, an important step in
the history of computers, was the design of a
mechanical general-purpose computer by the
British mathematician Charles Babbage. It
was first described in 1837, but Babbage
continued to work on the design until his
death in 1871. Because of financial, political,
and legal issues, the engine was never built.
In its logical design the machine was essen-
completed general-purpose computers by
about 100 years.
Some believe that the technological limita-
tions of the time were a further obstacle to
the construction of the machine; others be-
lieve that the machine could have been built
successfully with the technology of the era if
funding and political support had been
stronger. Charles Babbage was notoriously
hard to work with and alienated a great num-
ber of people who had at first supported him,
including his engineer Joseph Clement.
Charles Babbage’s first attempt at a mechan-
ical computing device was the difference en-
gine, a special-purpose calculator designed
to tabulate logarithms and trigonometric
functions by evaluating approximate polyno-
mials. As this project faltered for personal
and political reasons, he realized that a much
more general design was possible and star-
ted work designing the analytical engine.
The input (programs and data) was to be
provided to the machine via punched cards, a
method being used at the time to direct
mechanical looms such as the Jacquard loom.
For output, the machine would have a print-
er, a curve plotter and a bell. The machine
would also be able to punch numbers onto
cards to be read in later. It employed ordin-
ary base-10 fixed-point arithmetic.
There was to be a store (i.e., a memory)
capable of holding 1,000 numbers of 50
decimal digits each (ca. 20.7kB). An arithmet-
ical unit (the "mill") would be able to perform
all four arithmetic operations, plus co