Generations of Computers

Generations of Computers

The history of computer development is often referred to in reference to the different generations of computing devices. Each of the five generations of computers is characterised by a major technological development that fundamentally changed the way computers operate, resulting in increasingly smaller, cheaper, more powerful and more efficient and reliable computing devices.

The journey starts in 1940 with vacuum tube circuitry and goes to the present day and the future computers expected with artificial intelligence.

First Generation (1940-56): Vacuum Tubes

• The first computers used vacuum tubes for circuitry and magnetic drums for memory.
• They 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.
• These computers relied on machine language, the lowest-level programming language understood by computers, to perform operations.
• They could solve only one problem at a time.
• Input was based on punched cards and paper tape, and output was displayed on printouts.
• 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 US Census Bureau in 1951.

Second Generation (1956-63): Transistors

• Transistors replaced vacuum tubes and ushered in the second generation of computers.
• The transistor, invented in 1947, was far superior to the vacuum tube, allowing computers to become smaller, faster, cheaper, more energy-efficient and more reliable.
• The transistor still generated a great deal of heat that subjected the computer to damage.
• These computers still relied on punched cards for input and printouts for output.
• These computers moved from cryptic binary machine language to symbolic, or assembly, languages, which allowed programmers to specify instructions in words.
• High-level programming languages were also being developed at this time, such as early versions of COBOL and FORTRAN.
• These were the first computers that stored their instructions in their memory, which moved from a magnetic drum to magnetic core technology.
• The first computer of this generation was developed for the atomic energy industry.

Third Generation (1964-71): Integrated Circuits

• The development of the integrated circuit was the hallmark of the third generation of computers.
• Transistors were miniaturised and placed on silicon chips, called semiconductors, which drastically increased the speed and efficiency of computers.
• 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.

Note: An integrated circuit (IC) is a small electronic device made out of a semiconductor material. The first integrated circuit was developed in the 1950s by Jack Kilby of Texas Instruments and Robert Noyce of Fairchild Semiconductor.

Fourth Generation (1971-Present): Microprocessors

• The microprocessor brought the fourth generation of computers, as thousands of integrated circuits were built onto a single silicon chip.
• What in the first generation filled an entire room could now fit in the palm of the hand.
• The Intel 4004 chip, developed in 1971, located all the components of the computer, from the central processing unit and memory to input/output controls, on a single chip.
• In 1981, IBM introduced its first computer for the home user, and in 1984, Apple introduced the Macintosh.
• Microprocessors also moved out of the realm of desktop computers and into many areas of life as more and more everyday products began to use microprocessors.
• As these small computers became more powerful, they could be linked together to form networks, which eventually led to the development of the Internet.
• Fourth-generation computers also saw the development of GUIs, mouse and handheld devices.

Fifth Generation (Present and Beyond): Artificial Intelligence

Fifth generation computing devices, based on artificial intelligence, are still in development stage, though there are some applications, such as voice recognition, that are being used today.

The use of parallel processing and superconductors is helping to make artificial intelligence a reality.

Quantum computation, molecular technology and nanotechnology will radically change the face of computers in years to come.

• The goal of fifth-generation computing is to develop devices that respond to natural-language input and are capable of learning and self-organisation.

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