The four generations of computers

The first operational electronic general-purpose computer, named the ENIAC (Electronic Numerical Integrator and Computer), was built in 1943 and used 18,000 vacuum tubes. It was constructed with government funding at the University of Pennsylvania's Moore School of Engineering, and its chief designers were Presper Eckert, Jr.

As commercial interest in computer technology intensified during the late 1950s and 1960s, the second generation of computer technology was introduced—based not on vacuum tubes but on transistors .

The third generation of computer technology was based on integrated circuit technology and extended from approximately 1964 to 1970. Jack Kilby of Texas Instruments and Robert Noyce of Fairchild Semiconductor were the first to develop the idea of the integrated circuit in 1959. The integrated circuit is a single device that contains many transistors.

The fourth generation of computer technology is based on the microprocessor. Microprocessors employ Large Scale Integration and Very Large Scale Integration techniques to pack thousands or millions of transistors on a single chip.