History of computer started from china around 500 BC when the first computer ABACUS was built

                                    History of computer

a. ABACUS (500 BC): It is widely believed that china devoted the abacus around 500 BC. A rectangular wooden frame with a mid bar. The Chinese abacus had horizontal wires and specific beads fixed across the mid bar. The abacus was used for addition and subtraction. The Japanese and the Russian soon made the own version of abacus.

b. Napier bone (1617): The Scottish mathematician Sir John Napier invented the Napier bone. A set of eleven rectangular rods made out of carved bones. This device was used for multiplication and division besides addition and subtraction.
c Pascal calculator: the first mechanical calculator was invented in 1942 by a French mathematician and philosopher called Blaise Pascal. This device was called Pascal calculator and was used for addition and subtraction only.
d. Arithmetic Replica: A German mathematician got Fried Leibniz modified the Pascal calculator in 1671 his device could add, subtract and multiply and divide.
e. Analytical and differential Engine: In 19 century Charles Babbage, Professor in Cambridge University. He invented the first mechanical and differential engine in 1930. Howard Aiken designed and built a computer with the electrical function. It required proper design in1946 and was named Mark 1. It remains in use 1959.
f. Electronic computer: Electronic computer first appeared in 1946. They were gradually upgraded.