1.- THE COMPUTER AGE
In the nineteenth century, machines changed the world.
Suddenly, people could travel more easily and contact one
another more quickly. Work changed, too, and many people
got jobs in factories. It was the start of the Industrial Age
the age of machines and factories.
The second half of the twentieth century saw the start of
the Computer Age. At first, computers were very difficult
to use, and only a few people understood them. But soon,
computers began to appear in offices and then homes. Today,
they are everywhere. Some people still say that they have
never used a computer, but they probably use computers
every day - they just do not realize it. This is because there
are computers in so many things: cars, televisions, radios,
washing machines...
When the first computers were built in the 1940s and
1950s, they were as big as a room. In 1949, the magazine
Popular Mechanics made a prediction: 'One day,' they said,
'computers will be really small; in fact, they will weigh less
than 1.5 tonnes.' Now, computer chips can be smaller than
the full stop at the end of this sentence. Over the past fifty or
sixty years, computers have changed much more than people
thought possible.
Activities:
1:Complete:
- The Industrial Age started
- Many people use computers
- The first computers were built
- The abacus was invented
- A french matematician made an
2.- IN THE BEGINNING
For thousands of years, humans have needed to count.
Families needed to know how many animals, how much
food, and how much land they had. This information was
important when people wanted to buy and sell things, and
also when people died or gor married. There were many
different ways to count and write down the numbers. The
Sumerians had three different ways: they used one for land,
one for fruit and vegetables, and one for animals. They could
count, but they had no easy way to do calculations.
Around 1900 to 1800 BC, the Babylonians invented a new
way to count using place values. This meant that two things
decided the size of a number: the digits (the numbers from 0
to 9), and the place where they were put. Today, we still use
place values to count. We can write any number using only
ten digits: for example, 134 means 1 x 100,3 x 10, and 4 x 1.
Computers also use place values when they do calculations.
They only use two digits (O and 1): for example, 11011 means
1 x 16, 1 x 8, O x 4, 1 x 2, and 1 x 1 (=27). Without place
values, fast calculations are impossible.
Between 1000 and 500 BC, the Babylonians invented the
abacus. It used small stones which they put in Lines. Each line
of stones showed a different place value. To do calculations
they moved stones from one line to another. Later, different
kinds of abacuses were made. Some of them were made
of wood and used coloured balls. It is also possible that
the abacus was first invented in China, but nobody really
knows.
Although an abacus can be very fast, it is not really a
machine because it does not do calculations automatically.
In the seventeenth century, people began to build calculating
machines. In 1642, the French mathematician Blaise Pascal
made an Arithmetic Machine. He used it to count money.
During the next ten years, Pascal made fifty more machines.
In the 1670s, a German called Leibnitz continued Pascal's
work and made a better machine. Leibnitz's machine was
called the Step Reckoner. It could do much more difficult
calculations than Pascal 's Arithmetic Machine. Interestingly,
Leibnitz's machine only used two digits (O and 1) for its
calculations- just like modern computers! In fact, calculating
machines like Leibnitz's Step Reckoner were used for the next
three hundred years, until cheap computers began to appear.
3.- THE FIRST COMPUTER
The word 'computer' used to mean a person, not a machine.
In the nineteenth century, builders and technicians needed
to know the answers to very difficult calculations in order
to do their work. They did not have the time to do these
calculations themselves, so they bought books of answers.
The people who did the calculations and wrote the books
were called computers.
In the 1820s, a British mathematician called Charles
Babbage invented a machine that did very difficult calculations
automatically. He called his machine a Difference Engine. He
began to build his machine, but he did not finish it because
he had a better idea. (Babbage never finished anything - he
always had a better idea and started working on something
new!) In fact, more than a hundred and fifty years later,
some technicians from the Science Museum in London built
Babbage's Difference Engine. It is still in the museum today.
The machine weighs about three tonnes, and it is nearly two
metres tall and three metres wide. And it works: in the early
1990s, it did a calculation and gave the right answer - 31
digits long!
Babbage did not finish making the Difference Engine
because he started work on a machine called an Analytical
Engine. The Analytical Engine could do more: for example,
it had a kind of memory. This meant that it was possible to
write programs for it, building on each answer and doing
more and more difficult calculations. For this reason, the
Analytical Engine is often seen as the first real computer.
However, Babbage never finished building this machine either!
A woman called Ada Lovelace worked with Babbage. She
was the daughter of Lord Byron, a famous English writer.
Most people did not understand Babbage's ideas, but Ada
did, because she was an excellent mathematician. She
knew that she could do extraordinary calculations with
the Analytical Machine, and she wrote a program for it.
Although the machine was never built, Ada Lovelace was
still the first computer programmer in the world. In 1979, a
modern computer programming language was named ADA.
Babbage's ideas were ahead of their time. Slowly, over
the next one hundred years, inventors began to build better
calculating machines. One of the best inventors of the
1930s was a German called Konrad Zuse. In 1938, he built
his first machine, the Z1, in his parents' living room in Berlin.
His later machines, the Z3 and Z4, were like modern
computers in many ways. They used only two digits (O and
1) to do all the calculations. AIso, Zuse wrote programs for
his machines by making holes in old cinema film. When he
put the film through the machines, they could 'read'
the programs and do very long and difficult calculations.
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