In 1614, John Napier developed Logarithm
In 1642, Blasé Pascal developed a mechanical calculator.
A German scientist Leibnitz modified this calculator.
In 1822, Charles Babbage developed a machine named Difference Engine. This can perform Addition and Subtraction.
In 1833, another machine named Analytical Engine was developed by Charles Babbage.
This is known as first mechanical computer. So he is known as the father of Computers.
The first computer Programmer was Lady Ada Lovelace. She worked along with Babbage for the development of Analytical Engine.
George Boole developed Boolean algebra in 1840
Herman Hollerith developed a tabulating machine. It used for a census in 1890.
The first general purpose computer was developed in 1941. Its known as ENIAC (Electronic Numerical Integrator and Calculator.