What is a Computer

Computers are electronic machines
which can accept data in a certain form, process the data and give the
results of the processing in a specified format as information.

Three basic steps are
involved in the process. First, data is fed into the computer’s
memory. Then, when the program is run, the computer performs
a set of instructions and processes the data. Finally, we can
see the results (the output) on the screen or in printed form (see the
diagram below).

Information in the form
of data and programs is known as software, and the
electronic and mechanical parts that make up a computer system are called
hardware. A standard computer system consists of three
main sections: the central processing unit (CPU), the main memory and
the peripherals.

Perhaps the most influential
component is the central processing unit. Its function
is to execute program instructions and coordinate the activities of
all the other units. In a way, it is the ‘brain’ of the computer. The
main memory holds instructions and data which are currently
being processed by the CPU. The peripherals are the
physical units attached to the computer. They include storage devices
and input/output devices.

Storage
devices (floppy, hard or optical
disks) provide a permanent storage of both data and programs. Disk
drives are used to handle one or more floppy disks. Input
devices enable data to go into the computer’s memory. The most
common input devices are the mouse and the keyboard.
Output devices enable us to extract the finished product
from the system. For example, the computer shows the output on the monitor
or prints the results onto paper by means of a printer.

On the rear panel of
the computer there are several ports into which we can plug a wide range
of peripherals — modems, fax machines, optical drives and scanners.

These are the main physical
units of a computer system, generally known as the configuration.