The Five Generations of Computers
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
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.
