Generation of computer The development of computer phases is called computer generation. The computer comes into existence during the second world war. The computer was developed in five distinct phases is known as the generation of computers. Each phase is characterized by the type of switching circuits used in the computers. The first generation of computer: (1946- 1959) The computers that were produced in this duration used Vacuum Tube and called the first generation computer such computers had been very big heavy and with a large number of internal circuits but had a small amount of information. The first electronic computer of first generation computers was the ENIAC ( electronic numerical integrator and calculator ) which was developed by J. Presper Eckert and J. W. Mauchly at Pennsylvania University in U.S.A the other developed computer of the first generation were Uni vac , ED SAC , and ED-VAC etc.