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A computer is a machine which manipulates data according to a list of
instructions.
Computers take numerous physical forms. The first devices that
resemble modern computers date to the mid-20th century (around 1940 -
1941), although the computer concept and various machines similar to
computers existed earlier. Early electronic computers were the size of
a large room, consuming as much power as several hundred modern
personal computers.[1] Modern computers are based on comparatively
tiny integrated circuits and are millions to billions of times more
capable while occupying a fraction of the space. [2] Today, simple
computers may be made small enough to fit into a wrist watch and be
powered from a watch battery. Personal computers in various forms are
icons of the information age and are what most people think of as "a
computer". However, the most common form of computer in use today is
by far the embedded computer. Embedded computers are small, simple
devices that are often used to control other devices--for example, they
may be found in machines ranging from fighter aircraft to industrial
robots, digital cameras, and even children's toys.
The ability to store and execute lists of instructions called programs
makes computers extremely versatile and distinguishes them from
calculators. The Church-Turing thesis is a mathematical statement of
this versatility: Any computer with a certain minimum capability is,
in principle, capable of performing the same tasks that any other
computer can perform. Therefore, computers with capability and
complexity ranging from that of a personal digital assistant to a
supercomputer are all able to perform the same computational tasks
given enough time and storage capacity.
It is difficult to identify any one device as the earliest computer,
partly because the term "computer" has been subject to varying
interpretations over time.
Originally, the term "computer" referred to a person who performed
numerical calculations (a human computer), often with the aid of a
mechanical calculating device. Examples of early mechanical computing
devices included the abacus, the slide rule and arguably the astrolabe
and the Antikythera mechanism (which dates from about 150-100 BC). The
end of the Middle Ages saw a re-invigoration of European mathematics
and engineering, and Wilhelm Schickard's 1623 device was the first of
a number of mechanical calculators constructed by European engineers.
However, none of those devices fit the modern definition of a computer
because they could not be programmed. In 1801, Joseph Marie Jacquard
made an improvement to the textile loom that used a series of punched
paper cards as a template to allow his loom to weave intricate
patterns automatically. The resulting Jacquard loom was an important
step in the development of computers because the use of punched cards
to define woven patterns can be viewed as an early, albeit limited,
form of programmability.
In 1837, Charles Babbage was the first to conceptualize and design a
fully programmable mechanical computer that he called "The Analytical
Engine".[3] Due to limited finance, and an inability to resist
tinkering with the design, Babbage never actually built his Analytical
Engine.
Large-scale automated data processing of punched cards was performed
for the U.S. Census in 1890 by tabulating machines designed by Herman
Hollerith and manufactured by the Computing Tabulating Recording
Corporation, which later became IBM. By the end of the 19th century a
number of technologies that would later prove useful in the
realization of practical computers had begun to appear: the punched
card, Boolean algebra, the vacuum tube (thermionic valve) and the
teleprinter.
During the first half of the 20th century, many scientific computing
needs were met by increasingly sophisticated analog computers, which
used a direct mechanical or electrical model of the problem as a basis
for computation. However, these were not programmable and generally
lacked the versatility and accuracy of modern digital computers.
instructions.
Computers take numerous physical forms. The first devices that
resemble modern computers date to the mid-20th century (around 1940 -
1941), although the computer concept and various machines similar to
computers existed earlier. Early electronic computers were the size of
a large room, consuming as much power as several hundred modern
personal computers.[1] Modern computers are based on comparatively
tiny integrated circuits and are millions to billions of times more
capable while occupying a fraction of the space. [2] Today, simple
computers may be made small enough to fit into a wrist watch and be
powered from a watch battery. Personal computers in various forms are
icons of the information age and are what most people think of as "a
computer". However, the most common form of computer in use today is
by far the embedded computer. Embedded computers are small, simple
devices that are often used to control other devices--for example, they
may be found in machines ranging from fighter aircraft to industrial
robots, digital cameras, and even children's toys.
The ability to store and execute lists of instructions called programs
makes computers extremely versatile and distinguishes them from
calculators. The Church-Turing thesis is a mathematical statement of
this versatility: Any computer with a certain minimum capability is,
in principle, capable of performing the same tasks that any other
computer can perform. Therefore, computers with capability and
complexity ranging from that of a personal digital assistant to a
supercomputer are all able to perform the same computational tasks
given enough time and storage capacity.
It is difficult to identify any one device as the earliest computer,
partly because the term "computer" has been subject to varying
interpretations over time.
Originally, the term "computer" referred to a person who performed
numerical calculations (a human computer), often with the aid of a
mechanical calculating device. Examples of early mechanical computing
devices included the abacus, the slide rule and arguably the astrolabe
and the Antikythera mechanism (which dates from about 150-100 BC). The
end of the Middle Ages saw a re-invigoration of European mathematics
and engineering, and Wilhelm Schickard's 1623 device was the first of
a number of mechanical calculators constructed by European engineers.
However, none of those devices fit the modern definition of a computer
because they could not be programmed. In 1801, Joseph Marie Jacquard
made an improvement to the textile loom that used a series of punched
paper cards as a template to allow his loom to weave intricate
patterns automatically. The resulting Jacquard loom was an important
step in the development of computers because the use of punched cards
to define woven patterns can be viewed as an early, albeit limited,
form of programmability.
In 1837, Charles Babbage was the first to conceptualize and design a
fully programmable mechanical computer that he called "The Analytical
Engine".[3] Due to limited finance, and an inability to resist
tinkering with the design, Babbage never actually built his Analytical
Engine.
Large-scale automated data processing of punched cards was performed
for the U.S. Census in 1890 by tabulating machines designed by Herman
Hollerith and manufactured by the Computing Tabulating Recording
Corporation, which later became IBM. By the end of the 19th century a
number of technologies that would later prove useful in the
realization of practical computers had begun to appear: the punched
card, Boolean algebra, the vacuum tube (thermionic valve) and the
teleprinter.
During the first half of the 20th century, many scientific computing
needs were met by increasingly sophisticated analog computers, which
used a direct mechanical or electrical model of the problem as a basis
for computation. However, these were not programmable and generally
lacked the versatility and accuracy of modern digital computers.