Generally speaking, computers can be classified into 5 Generations. Each generation lasted for a certain period of time, and each gave us either a new and improved computer or an improvement to the existing computer.
1) First Generation (1936-1956) Vacuum Tubes
2) Second Generation (1956-1963) Transistors
3) Third Generation (1964-1971) Integrated Circuits
4) Fourth Generation (1971-Present) Microprocessors
5) Fifth Generation (Present and Beyond) Artificial Intelligence
First Generation (1936-1956) Vacuum Tubes
A.In 1937 the first electronic digital computer was built by Dr. John V. Atanasoff and Clifford Berry. It was called the Atanasoff-Berry Computer (ABC). In 1943 an electronic computer name the Colossus was built for the military.
B.The first computers used vacuum tubes for circuitry and magnetic drums for memory, and were often enormous, taking up entire rooms. They were very expensive to operate and in addition to using a great deal of electricity, generated a lot of heat, which was often the cause of malfunctions.
C.First generation computers relied on machine language, the lowest-level programming language understood by computers, to perform operations, and they could only solve one problem at a time. Input was based on punched cards and paper tape, and output was displayed on printouts.
D.The UNIVAC and ENIAC computers are examples of first-generation computing devices. The UNIVAC was the first commercial computer delivered to a business client, the U.S. Census Bureau in 1951.
Second Generation (1956-1963) Transistors
A.The second generation computers used transistors. The scientists at Bell laboratories developed transistor in 1947. These scientists include John Barden, William Brattain and William Shockley.
B.The transistor was far superior to the vacuum tube, allowing computers to become smaller, faster, cheaper, more energy-efficient and more reliable than their first-generation predecessors. Though the transistor still generated a great deal of heat that subjected the computer to damage, it was a vast improvement over the vacuum tube.
C.Second-generation computers still relied on punched cards for input and printouts for output. The size of the computers was decreased by replacing vacuum tubes with transistors.
D.The examples of second generation computers are IBM 7094 series, IBM 1400 series and CDC 164 etc.
Third Generation (1964-1971) Integrated Circuits
A.The development of the integrated circuit was the hallmark of the third generation of computers. Transistors were miniaturized and placed on silicon chips, called semiconductors, which drastically increased the speed and efficiency of computers.
B.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.
C.Instead of punched cards and printouts, users interacted with third generation computers through keyboards and monitors and interfaced with an operating system, which allowed the device to run many different applications at one time with a central program that monitored the memory. Computers for the first time became accessible to a mass audience because they were smaller and cheaper than their predecessors.
D.The examples of third generation computers are IBM 370, IBM System/360, UNIVAC 1108 and UNIVAC AC 9000 etc.
Fourth Generation (1971-Present) Microprocessors
a.fourth generation computers started with the invention of Microprocessor. The Microprocessor contains thousands of ICs.
B.Ted Hoff produced the first microprocessor in 1971 for Intel. It was known as Intel 4004. The technology of integrated circuits improved rapidly.
C.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.
D.The examples of fourth generation computers are Apple Macintosh & IBM PC.
Fifth Generation (Present and Beyond) Artificial Intelligence
A.Scientists are working hard on the 5th generation computers with quite a few breakthroughs. It is based on the technique of Artificial Intelligence (AI).
B.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.
C.They are trying to create a computer with real IQ with the help of advanced programming and technologies.
D.IBM Watson computer is one example that outsmarts Harvard University Students. The advancement in modern technologies will revolutionize the computer in future.