<Ol> <Li> First generation: Thermionic vacuum tubes . Mid-1940s . IBM pioneered the arrangement of vacuum tubes in pluggable modules . The IBM 650 was a first - generation computer . </Li> <Li> Second generation: Transistors. 1956 . The era of miniaturization begins . Transistors are much smaller than vacuum tubes, draw less power, and generate less heat . Discrete transistors are soldered to circuit boards, with interconnections accomplished by stencil - screened conductive patterns on the reverse side . The IBM 7090 was a second - generation computer . </Li> <Li> Third generation: Integrated circuits (silicon chips containing multiple transistors). 1964 . A pioneering example is the ACPX module used in the IBM 360 / 91, which, by stacking layers of silicon over a ceramic substrate, accommodated over 20 transistors per chip; the chips could be packed together onto a circuit board to achieve unheard - of logic densities . The IBM 360 / 91 was a hybrid second - and third - generation computer . </Li> </Ol> <Li> First generation: Thermionic vacuum tubes . Mid-1940s . IBM pioneered the arrangement of vacuum tubes in pluggable modules . The IBM 650 was a first - generation computer . </Li> <Li> Second generation: Transistors. 1956 . The era of miniaturization begins . Transistors are much smaller than vacuum tubes, draw less power, and generate less heat . Discrete transistors are soldered to circuit boards, with interconnections accomplished by stencil - screened conductive patterns on the reverse side . The IBM 7090 was a second - generation computer . </Li> <Li> Third generation: Integrated circuits (silicon chips containing multiple transistors). 1964 . A pioneering example is the ACPX module used in the IBM 360 / 91, which, by stacking layers of silicon over a ceramic substrate, accommodated over 20 transistors per chip; the chips could be packed together onto a circuit board to achieve unheard - of logic densities . The IBM 360 / 91 was a hybrid second - and third - generation computer . </Li>

What is the example of fifth generation computer