4 generations of computers
generation one
the first generation of computers where in 1945-1955. they were made up of vacuum tubes and programmed using wiring plugboards. they were also very large. they were mostly used for numeral calculations.
generation two
1955-1965. this computer was a lot smaller and mainly used for scientific and enigineering applications. the mainframes were made up of transmitters
generation 3
1965-1980. they were the first models which used multi-programmed batch processing. mainframes based on small ICs were used.
generation 4
this is the most modern generation which was created in 1980 and is still used today. they have virtual machines and network computers