Computers - Bloomington Public Schools

Great Inventions
written by Bob
Computers help society function in many vital ways, often without our being aware of them.
Computers control traffic lights and factory operations. They scan bar codes at checkout
counters and track store inventories. They monitor banking, credit card, and cash machine
transactions. Computer chips in our cars, home appliances, radios, televisions, and stereos
help us use these and many other products every day. And computers link schools,
governments, businesses, and people throughout the world.
Every time you call a friend on the telephone, you are probably using several computers. The
telephone itself may have a tiny computer chip that remembers names and numbers. A
computer at your local telephone company may automatically connect the call. If you are
phoning long-distance, a computer on an orbiting satellite may relay your call to another part
of the world. Even the operator may be a computer that answers with a human voice and
recognizes your spoken commands.
History of Computers
For thousands of years, people have needed to count and calculate. In ancient times, the
Egyptians, Greeks, and Chinese began using the abacus, a calculating device with rows of
beads on wires. The first true calculating machine, an adding machine, was built in 1642 by
the French mathematician Blaise Pascal. It consisted of interlocking gears and wheels
mounted on axles, and it added numbers that were dialed on its wheels. In the late 1600's, the
German philosopher and mathematician Gottfried Wilhelm von Leibniz devised a system of
gears that could multiply as well as add.
The New Book of Knowledge Encyclopedia
The First Computers
The next major advance occurred in the early 1800's, when the English mathematician Charles Babbage built
what many people consider to be the first true computer. Babbage created a model of what he called an
analytical engine, a device that could perform any set of instructions fed to it by cards with holes punched in
them. But Babbage never produced a working machine. (In 1991, the National Museum of Science and
Technology in London built a working analytical engine using Babbage's plans. Weighing hundreds of pounds
and operated with a hand crank, it has never calculated a wrong answer.)
The first computer that used punched cards was created to win a contest. Because it took years to tabulate
the results of the 1880 census by hand, the U.S. government sponsored a competition to devise a faster
method for the 1890 census. The contest was won by Herman Hollerith, a statistician. Hollerith built a
mechanical coding and decoding process based on the positions of holes punched in cards. A hole in a
certain place on a card represented a piece of information, such as a person's age or occupation. By the end
of the 1800's, people were collecting so much information that computing machinery became a necessity.
For forty years after the 1890 census, computers used slow mechanical parts that often broke down. During
the 1900's, electrical components increased the power and efficiency of computers while reducing their size.
In the 1930's, Howard Aiken and others developed a way to use vacuum tubes instead of mechanical parts to
perform many computer functions. Then, during World War II (1939-45), fast computers were needed to
control sophisticated weapons systems and calculate, for example, the flight paths of missiles.
In the mid-1940's, mathematician John von Neumann came up with the idea of storing programs inside
computers and avoiding the need to rewire them for every new task. The first programs were written in lowlevel machine language or assembly language.
The New Book of Knowledge Encyclopedia
Computers are used in airplanes and automobiles to control
the way that fuel is injected into the engine, and they are used
to monitor every part of the production process in most
modern factories. Computers help people write reports, draw
pictures, and keep track of information. Since the invention of
the Internet, computers are also used to gather information
from digital libraries located all over the world, to send and
receive electronic messages (e-mail), and to work, shop, and
bank from home.
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"computer." Britannica Elementary Encyclopedia. Encyclopædia Britannica Online School Edition. Encyclopædia Britannica, 2010. Web.
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Common Computer Uses
Computers have been used to solve scientific and engineering problems, such as designing weapons and
modeling the first hydrogen nuclear reaction. Efforts to create models of weather conditions and design
nuclear weapons have led to the most advanced supercomputers.
Another important computer application is databases. A database is an organized collection of data together
with a special index. For example, if a person calls an airline to reserve a flight to Orlando, Florida, an airline
employee checks a reservation database to see which airplanes have seats available.
Spreadsheets are used for bookkeeping and to create financial reports. For example, a business manager
might use a spreadsheet to see how using a new ingredient would affect the cost of manufacturing a product.
Computer-aided design (CAD) software is used to produce two and three-dimensional blueprints for buildings
and machinery. Such software has evolved to include programs for creating illustrations, animations, and
special effects used in motion pictures.
Probably the most common application for computers is word processing. Basic word processing involves
combining text and images to produce a document that can be printed.
The Internet connects thousands of computers all over the world through a wide area network, or a network
of networks.
Britannica Elementary Encyclopedia
A computer is an electronic device that can store, retrieve, and manipulate data, or information. Computers run on
programs. Programs are lists of instructions. Computers can be as small as a wristwatch. They can also be large enough
to fill several rooms. Personal computers fit on top of a desk and can perform a wide variety of tasks. Tiny computers
are used to control other machines, like cameras, washing machines, and airplanes.
Early History of Computers
The first machine to run on a program like a computer was made in 1801. It was a loom that used punched paper cards
to weave complicated designs automatically. In 1837 Charles Babbage invented a mechanical computer that could be
programmed. Similar machines used punched cards to process information for the U.S. Census in 1890.
In World War II, British scientists built a large computer called Colossus. They used the device to break German codes.
In 1943 scientists at Pennsylvania State University developed a computer they called ENIAC. This machine used a
paper tape to store instructions. This tape was called a "stored program." From that point on, the name "computer" was
used for machines with stored programs.
Around this time, scientists came up with a binary system for computer programs. "Binary" means two. The system is
made up of two numbers: zero and one. Zero means no and one means yes. These commands can be multiplied
millions and billions of times. Most computer circuits run on the binary system.
A series of inventions led to smaller and more powerful computers. In the 1950s, computers that ran on vacuum tubes
filled an entire room. In the 1960s, transistors made computers smaller, cheaper, and faster. In the 1970s, the
microprocessor was invented. This led to the computer chip, a tiny circuit on a chip made of silicon. Computer chips
allow computers to perform at amazing speeds.
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