A computer may be defined as a device that can store, process, and retrieve data as and when required. a generation of computers is called the step-by-step growth in the hardwares of the computer.
Generation of computers
- First-generation (1942-1955)
- Second generation (1955-1964)
- Third generation (1964-1975)
- Fourth generation (1975)
- Fifth-generation (Yet to come)
Vacuum tubes and valves were used in the first-generation computers. ENIAC (Electronic Numeric Integrator and Computer), EDVAC (Electronic Discrete Variable Automatic Computer), EDSAC (Electronic Delay Storage Automatic Calculator), etc., were some of the computers of this generation. these vacuum tube computers were very large in size (thousands of square feet).
Second generation (1955-1964)
The semiconductor device, Transistor was invented in 1947. in second-generation computers, vacuum tubes were replaced by transistors. Introducing the transistor in computers reduced the size, and power requirements cost while increasing the speed and reliability, PDP-1 and NCR-304 were a few computers of the second generation.
Third generation (1964-1975)
The third generation was based on IC(Integrated Circuit) technology. IC technology made it possible to integrate a large number of circuit elements into a very small surface of silicon known as a ‘chip’. In third-generation, IC technology further reduced the size, power requirements, and cost while increasing the speed, computing power, and reliability.
IBM 360, PDP-8, PDP-11, CRAY-1, and VAX were some examples of third-generation computers. SSI (Small Scale Integration – few logic gates on a single chip), MSI (Medium Scale Integration – more than a hundred logic gates on a single chip), and LSI (Large Scale Integration – more than a thousand logic gates on a single chip) technologies were used to manufacture the third generation computers.
Fourth generation (1975)
Advancements in IC technology created the computers of the fourth generation. VLSI (Very large-scale Integration) technology of ICs made it possible to integrate more than a thousand logic gates on a single chip. this made it possible to design the complete circuit of the Central Processing Unit (CPU) of a computer system within a single chip.
The fourth-generation computer, which has VLSI chips as its brain, led to the development of very small but extremely powerful computers. Those computers were actually microcomputers having microprocessors as their CPU.
Fifth-generation (Yet to come)
Scientists are still on work to bring a machine with genuine IQ, the ability to reason logically, and with real knowledge of the world. thus unlike the last four generations which naturally followed its predecessor, the fifth generation will be totally different and new.
Here the above pictures show the some of electronic devices used for manufacturing computers of different generations.