The four generations of computers!
1st generation! 1940-56
The first generation of computers used vacuum tubes* and magnetic drums* for memory, which was limited. They were expensive to run and not many people could afford them.
2nd Generation! 1956-63
The second generation used transistors and allowed the computer to be smaller and much faster.
3rd Generation 1964-71
The integrated circuit was invented and transistors were made smaller and placed on silicone chips.
4th generation 1971- now!
We now have the microprocessor, and computers are considerably thinner, so we can fit thousands of intergrated circuits on to just one silicone chip.
*Vacuum tubes- Tube with no air!
*Magnetic drums- Direct access storage device