First generation :-The first generation computers used vacuum tubes for circuitry and magnetic drums for memory they are taking space of entire room
- They are very expensive to operate.
- By using it generated a lot of heat , electricity which we often the cause of malfunctions.
- Out put was displayed on printouts
- UNIAC and ENIAC computers are the example of first generation computing devices.
- The UNIAC was the first computer used by the U.S census bureau in the year 1951.
* UNIAC = Universal automatic computers
* ENIAC = Electronic numerical integrator & computer
Second generation :-In this generation transistors are used instead of vacuum tubes
- this generation uses moved for Machine level language and assembly language.
- in this generation also the instruction are stored in magnetic drums.
Third generation :The main thing in this generation is the development of integrated circuits.
- By this computers become accessible to a mass audience because they were smaller & cheaper.
- Chips are used entire processing unit i.e. in C.P.U.
- By this it takes less space , faster and requires less heat energy.
Fourth generation :-The microprocessors brought the fourth generation of computers as thousands of I.C was built onto a single silicon chip.
- The Intel 4004 chip, developed in 1971, locates all the components of the computers from the C.P.U & memory to I/O controls on a single chip.
- In 1981 IBM introduced its first computer for the home user and in 1984 APPLE introduced the Macintosh.
- It also development of GUIs, the mouse & handheld devices .
NOTE :- GUI = Graphical User Interface.