There are five generations of computer:
1. First Generation: Vacuum Tubes (1940-1956)
- The first computer systems used vacuum tubes for circuitry and magnetic drums for memory, and were often enormous, taking up entire rooms. These computers were very expensive to operate and in addition to using a great deal of electricity, the first computers generated a lot of heat, which was often the cause of malfunctions.
- First generation computers relied on machine language to perform operations and solve one problem at a time. It would take operators days or even weeks to setup a new problem. Input was based on punched cards and paper tape, and output was displayed on printouts.
- 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.
2. Second Generation: Transistors (1956-1963)
- Transistor was used in place of vacuum tube, allowing computers to become smaller, faster, cheaper, more energy-efficient and more reliable than first generation. Though the transistor still generated a great deal of heat but was a vast improvement over the vacuum tube. Second-generation computers still relied on punched cards for input and printouts for output.
- Second-generation computers moved from binary to assembly languages. High-level programming languages were also being developed at this time, such as early versions of COBOL and FORTRAN. These were also the first computers that stored their instructions in their memory, which moved from a magnetic drum to magnetic core technology.
- The first computers of this generation were developed for the atomic energy industry.
3. Third Generation: Integrated Circuits (1964-1971)
- 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.
- Used keyboards and monitors instead of punched cards and printouts 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.
4. Fourth Generation: Microprocessors (1971-Present)
- The microprocessor brought the 4th generation of computers, as thousands of integrated circuits were built onto a single silicon chip. 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.
- 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, the mouse and handheld devices.
5. Fifth Generation: Artificial Intelligence (Present and Beyond)
- Fifth generation computing devices, based on artificial intelligence, are still in development, 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 and molecular 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-organization.
