In 1823, the British mathematician Charles Babbage developed the
concept of the difference engine considered as the forerunner of
the modern digital computer.
In reality it was a special-purpose calculator to help the Bristih
navy draw up various nautical tables. These could be tables of multiplication,
logarithms, sines, and cosines, or physical measurement and observations.
Later on the Babbage developed the analytical engine that was conceived
as a general-purpose computer comprising: the memory for data storage
entered by punch cards; it was responsible to supply the necessary
instructions for the machine to execute all the arithmetical operations
using a ten-digit recorder, as well as the processing unit, that
allows the delivering of printed output.
It it interesting to notice that Babbage has taken the idea of punched
cards from Joseph Marie Jacquard, who invented an attachment to
the loom in 1805.
Around 1848, the British logician, George Boole developed the theory
of the symbolic logic describing the possibility to express logic
in very simple algebraic systems giving birth of the Boolean algebra,
which has only 0 and 1 as an answer in numerical terms.
Thus the modern computers can make use of this binary system, with
their logic parts carrying out binary operations.
In 1890, William S. Burroughs invented the adding and listing machine
using punched cards. The same principle was used by Herman Hollerith
to help in solving the compilation problems arising during the 1890
United States demographic census.
At the end of XIX century the concept of the analog computer had
been done by researches of James and William Thomson later as known
as Lord Kelvin. They were responsible for the design of the planimeter,
an apparatus comprising a ball and a disk integrator. Lord Kelvin
used this integrator in a harmonic analyser as well as a tide predictor.
Unlike digital computers, which started out as simple mechanical
devices and then went through a brief electromechanical period during
the later thirties, finally becoming an electronic machine in 1940
only. In this way as a historical and technical approach the development
of the electronic computer will be commented considering several
upgrading stages also known as families or computers generations.