Tabulating Machine:-
Dr. Herman Hollerith was an American census statisticians .He developed Tabulating Machine in 1887 AD .The machine was used to tabulate US census record in 1890 . The previous census in 1880 AD had taken nearly seven years.
His tabulating system was the first to make practical use of the punched card in data processing .Hit tabulating machine became the nucleus of today’s computing fields.
Hollerith establish the tabulating machine company in 1986 AD to manufacture his inventions. This company later in 1974 AD merged with other companies to form the big international Business Machine (IBM) Corporation .IBM is one of the largest somputer5 manufacring company in the world even today.
Electromechanical Computer
MARK-1
In 1937 AD ,Howard aiken professor of Harvard Unversity developed an automatic calculating machine called mark-1
The Mark 1 became operational after seven years in 1944 AD .It is also called automatic sequence controlled calculator . It was the first electromechanical computer.It was 51 feet long, 8 feet tall and 3 feet wide having 1800 vacum tubes. The vacuum tubes were used to store data in the memory.It used a program to guide it through a long series of calculations .
ABC
ABC is the short form of Atanasoft Berry compter .It was the first digital computer designed by Dr.John V. Atanasoft and his assistant Clifford Berry in 1942 AD. It used vacuum tubes as a main memory.This computer was designed for solving systems of simultaneous linear equations.Similarly in 1944 AD Howard Aiken developed another computer called Mark-II .It was huge in size and occupied 15000 square feet using 19000 vacuum tubes.It consumed 130 KW electrijcal power for operation.This machine was mainly used by military to compute firing and ballistic.
