The document discusses the history and components of computers. It describes how Charles Babbage originated the concept of a programmable computer in the 19th century. A computer takes input, processes it, stores the output and can be programmed to solve different problems. Computers range in size from supercomputers that perform complex calculations to small computers embedded in devices. Common types of computers include desktop PCs, laptops, handheld devices, and tablet PCs.

3. A computer is a general
purpose device that can be
programmed to carry out a set
of arithmetic or logical
operations. Since a sequence of
operations can be readily
changed, the computer can
solve more than one kind of
problem.

4. Conventionally, a computer consists of
at least one processing element, typically a
central processing unit (CPU) and some form
of memory. The processing element carries
out arithmetic and logic operations, and a
sequencing and control unit that can change
the order of operations based on stored
information. Peripheral devices allow
information to be retrieved from an external
source, and the result of operations saved and
retrieved.

6. Charles Babbage,
He was an English polymath.He was a
mathematician, philosopher, inventor and
mechanical engineer, who is best remembered
now for originating the concept of a
programmable computer.
Considered a "father of the computer",[2]
Babbage is credited with inventing the first
mechanical computer that eventually led to
more complex designs. His varied work in other
fields has led him to be described as "pre-
eminent" among the many polymaths of his
century.

7. The first recorded use of the word
“computer” was in 1613 in a book called “The yong
mans gleanings” by English writer Richard
Braithwait I haue read the truest computer of
Times, and the best Arithmetician that euer
breathed, and he reduceth thy dayes into a short
number. It referred to a person who carried out
calculations, or computations, and the word
continued with the same meaning until the middle
of the 20th century. From the end of the 19th
century the word began to take on its more familiar
meaning, a machine that carries out computations.[

8. The history of the modern
computer begins with two
separate technologies, automated
calculation and programmability.
However no single device can be
identified as the earliest
computer, partly because of the
inconsistent application of that
term

9. A few precursors are worth mentioning though,
like some mechanical aids to computing, which were
very successful and survived for centuries until the
advent of the electronic calculator, like the Sumerian
abacus, designed around 2500 BC of which a
descendant won a speed competition against a
contemporary desk calculating machine in Japan in
1946, the slide rules, invented in the 1620s, which
were carried on five Apollo space missions, including
to the moon[7] and arguably the astrolabe and the
Antikythera mechanism, an ancient astronomical
analog computer built by the Greeks around 80 BC.

11. The way a computer functions is very similar
to the way you solve a problem using pen and
paper. The first operation is we called the input.
Input involves obtaining data.
The second operation is we called the processing.
Processing involves manipulation of the data.
Manipulation means adding, subtracting,
multiplying, comparing, etc. The third operation is
we called output.
Output involves sending the results of the
processing, the information, to the users. The
fourth operation, storage, involves keeping the
data in an electronic store.

12. Input means putting data into the computer. To do
this, we usually use a device called a keyboard,
which look like a typewriter.
Processing is done by a processor. The processor is
like the brain of the computer. The processor does
its job by executing program.
A program is a set of a instructions for completing a
job.
The result of the processing are sent to output
units. The commonly used output units are printer
and monitors. The results produced by the
processor are called output.
Output is also known as information, which is the
summarize data.

13. Data by itself, is not directly useful. However,
information has meaning and is useful.
The results of the processing are called the output.
Output is also known as information.

14. The fourth operation, storage, describes a
computer’s electronic storage capacity.
Look at the block diagram of a computer.
The arrow show how data is moved from the input to the
processor for processing and sent out as output or information.
The processed data is saved into the storage and retrieved from it
when needed.

17. Computers range in size and
capability. At one end of the scale
are supercomputers, very large
computers with thousands of linked
microprocessors that perform
extremely complex calculations. At
the other end are tiny computers
embedded in cars, TVs, stereo
systems, calculators, and appliances.
These computers are built to
perform a limited number of tasks.

18. Desktop computers
Desktop computers are designed for use at a desk or
table. They are typically larger and more powerful than other
types of personal computers. Desktop computers are made up of
separate components. The main component, called the system
unit, is usually a rectangular case that sits on or underneath a
desk. Other components, such as the monitor, mouse, and
keyboard, connect to the system unit.

19. Laptop computers
Laptop computers are lightweight mobile PCs with a thin
screen. They are often called notebook computers because of
their small size. Laptops can operate on batteries, so you can
take them anywhere. Unlike desktops, laptops combine the CPU,
screen, and keyboard in a single case. The screen folds down onto
the keyboard when not in use.

20. Laptop computers
Laptop computers are lightweight mobile PCs with a thin
screen. They are often called notebook computers because of
their small size. Laptops can operate on batteries, so you can
take them anywhere. Unlike desktops, laptops combine the CPU,
screen, and keyboard in a single case. The screen folds down onto
the keyboard when not in use.

21. Handheld computers
Handheld computers, also called personal digital
assistants (PDAs), are battery-powered computers small enough to
carry almost anywhere. Although not as powerful as desktops or
laptops, handhelds are useful for scheduling appointments,
storing addresses and phone numbers, and playing games. Some
have more advanced capabilities, such as making telephone calls
or accessing the Internet. Instead of keyboards, handhelds have
touch screens that you use with your finger or a stylus (a pen-
shaped pointing tool).

22. Tablet PC
Tablet PCs are mobile PCs that combine features of
laptops and handhelds. Like laptops, they're powerful and have a
built-in screen. Like handhelds, they allow you to write notes or
draw pictures on the screen, usually with a tablet pen instead of a
stylus. They can also convert your handwriting into typed text.
Some Tablet PCs are “convertibles” with a screen that swivels and
unfolds to reveal a keyboard underneath.