The first computer was the Atanasoff-Berry Computer, which was built from 1939 to 1942, according to a ruling issued by Federal Judge Earl R. Larson in 1973. This ruling invalidated the patent granted to Professors J. Presper Eckert and John Mauchly, who developed the ENIAC at the University of Pennsylvania.
Some historians consider the computing machine conceived by Charles Babbage in 1837 and built by his son Henry in 1910 to be the first mechanical computer. Konrad Zuse built the first electro-mechanical programmable computer, the Z1, between 1936 and 1938.
The Atanasoff-Berry Computer was built by Professor John Vincent Atanasoff and graduate student Cliff Berry at what is now Iowa State University. The machine used vacuum tubes, performed digital computations and used Boolean logic, but it lacked a central processing unit. The ENIAC was the first fully functional electronic computer with a CPU and was built from 1942 to 1946.