The development of electronic computers can be divided into five generations depending upon the technologies used. A computer generation is born when there is a departure in technology.
First Generation of Computers (1942-1955)
The beginning of commercial computer age is from UNIVAC (Universal Automatic Computer). It was developed by two scientists Mauchly and Echert at the Census Department of United States in 1947. They were based on vacuum tubes. Examples of first generation computers are ENIVAC and UNIVAC-1
Vacuum tubes were the only electronic component available during those days.
Vacuum tube technology made possible to make electronic digital computers.
These computers could calculate data in milliseconds.
The computers were very large in size.
They consumed a large amount of energy.
They heated very soon due to thousands of vacuum tubes. Therefore needed air conditioning hence they were not very reliable.
Costly commercial production.
Limited commercial use.
Very slow speed.
Limited programming capabilities.
Used machine language only.
Used magnetic drums which provide very less data storage.
Used punch cards for input.
Not versatile and very faulty so constant maintenance was required.
Second Generation Computers (1955-1964)
The second generation computers used transistors. The scientists at Bell laboratories developed transistor in 1947. The size of the computers was decreased by replacing vacuum tubes with transistors. The examples of second generation computers are IBM 7094 series and IBM 1400 series
Smaller in size as compared to the first generation computers.
The Third generation computers used the integrated circuits (IC). Kilby developed the concept of integrated circuit in 1958. It was an important invention in the computer field. The first IC was invented and used in 1961. The size of an IC is about ¼ square inch. A single IC chip may contain thousands of transistors. The computer became smaller in size, faster, more reliable and less expensive. The examples of third generation computers are IBM 370 and UNIVAC AC 9000.
Smaller in size as compared to previous generations.
Used less energy
Produced less heat as compared to the previous two generations of computers.
Better speed and could calculate data in nanoseconds.
Used fan for heat discharge to prevent damage.
Maintenance cost was low because hardware failure was rare.
Highly sophisticated technology required for the manufacturing of IC chips.
Fourth Generation Computers (1975-Present)
The fourth generation computers started with the invention of Microprocessor. The Microprocessor contains thousands of ICs. Ted Hoff produced the first microprocessor in 1971 for Intel. It was known as Intel 4004. The technology of integrated circuits improved rapidly. The LSI (Large Scale Integration) circuit and VLSI (Very Large Scale Integration) circuit was designed. It greatly reduced the size of computer. The size of modern Microprocessors is usually one square inch. It can contain millions of electronic circuits. The examples of fourth generation computers are Apple Macintosh & IBM PC.
More powerful and reliable than previous generations.
The latest technology is required for manufacturing of Microprocessors.
Fifth Generation Computers (Present & Beyond)
Scientists are working hard on the 5th generation computers with quite a few breakthroughs. It is based on the technique of Artificial Intelligence (AI). Computers can understand spoken words & imitate human reasoning. Can respond to its surroundings using different types of sensors. Scientists are constantly working to increase the processing power of computers. They are trying to create a computer with real IQ with the help of advanced programming and technologies. The advancement in modern technologies will revolutionize the computer in future. In short this generation shall have computers capable of seeing, hearing, feeling, talking and so forth in the same way as humans.