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.
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