Generations of Computer
First Generation (1940-1956) Vacuum Tubes
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. 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. 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
Transistors replaced vacuum tubes and ushered in the second generation of computers. The transistor was invented in 1947 but did not see widespread use in computers until the late 1950s. 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. Second-generation computers still relied on punched cards for input and printouts for output. Second-generation 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 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.
Third Generation (1964-1971) Integrated Circuits
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. 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.
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, the mouse and handheld devices.
Fifth Generation (Present and Beyond) Artificial Intelligence
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.
History of Internet
The conceptual foundation for creation of the Internet was largely created by three individuals and a research conference, each of which changed the way we thought about technology by accurately predicting its future:
Vannevar Bush wrote the first visionary description of the potential uses for information technology with his description of the "memex" automated library system.
Norbert Wiener invented the field of Cybernetics, inspiring future researchers to focus on the use of technology to extend human capabilities.
The 1956 Dartmouth Artificial Intelligence conference crystallized the concept that technology was improving at an exponential rate, and provided the first serious consideration of the consequences.
Marshall McLuhan made the idea of a global village interconnected by an electronic nervous system part of our popular culture.
In 1957, the Soviet Union launched the first satellite, Sputnik I, triggering US President Dwight Eisenhower to create the ARPA agency to regain the technological lead in the arms race. ARPA appointed J.C.R. Licklider to head the new IPTO organization with a mandate to further the research of the SAGE program and help protect the US against a space-based nuclear attack. Licklider evangelized within the IPTO about the potential benefits of a country-wide communications network, influencing his successors to hire Lawrence Roberts to implement his vision.
Roberts led development of the network, based on the new idea of packet switching invented by Paul Baran at RAND, and a few years later by Donald Davies at the UK National Physical Laboratory. A special computer called an Interface Message Processor was developed to realize the design, and the ARPANET went live in early October, 1969. The first communications were between Leonard Kleinrock's research center at the University of California at Los Angeles, and Douglas Engelbart's center at the Stanford Research Institute.
The first networking protocol used on the ARPANET was the Network Control Program. In 1983, it was replaced with the TCP/IP protocol invented Wby Robert Kahn, Vinton Cerf, and others, which quickly became the most widely used network protocol in the world.
In 1990, the ARPANET was retired and transferred to the NSFNET. The NSFNET was soon connected to the CSNET, which linked Universities around North America, and then to the EUnet, which connected research facilities in Europe. Thanks in part to the NSF's enlightened management, and fueled by the popularity of the web, the use of the Internet exploded after 1990, causing the US Government to transfer management to independent organizations starting in 1995.