What Is Computer & Its Components ?

What Is Computer ?

The word computer has been derived from the Latin word computare, which means to compute or calculate. A computer can be defined as an electronic device used to calculate and manipulate the data (i.e. input) and generates an output in the form of useful information by following a set of procedural instructions. British scientist Charles Babbage is considered as the Father of Computer. He invented the first mechanical computer in early 19^th century and further in 1833, he conceived a automatic analytical engine for performing arithmetic functions. Alan Mathison Turing is widely regarded as Father of Modern Computers or Father of theoretical computer science and Artificial Intelligence (AI).

Components Of Computer

The computer system comprises of the following four main components :

1.     Input Unit : It consists of those devices through which user can enter the data into a computer. It links a computer to the external environment. It translates the data into computers understandable form. Some input devices are :

· Keyboard is  used to enter data or information, which may be in numeric form or alphabetical form, in a computer system.

· Mouse is a pointing device which provides a means to input data and commands in graphic form by selecting through moving an arrow called pointer.

· Trackball is another pointing device which is alternative to a mouse.

· Joystick is an input device that moves in all directions and controls the movement of the cursor.

· Scanner is an optical input device and uses light as an input source to convert an image into an electronic form that can be stored on the computer.

· Touch Screen is an electronic visual display that can detect the presence and location of a touch within the display area.

2.     Output Unit : The unit contains those devices that provide the desired output (results) in the human acceptable format. Some of the output devices are

·  Monitor is also known as Visual Display Unit (VDU). The monitor is provided along with the computer to view the display result. The popular types of monitor are

·   LCD (Liquid Crystal Display), a special type of liquid is sandwiched between two plates. It is a thin, flat and light weight screen made up of any number of colour or monochrome pixels arranged in front of light source.

·   LED (Liquid/Light Emitted Diode) is an electronic device that emits light when electrical current is passed through it.

· TFT (Thin Film Transistor) is a LCD with active-matrix dispalays, each pixel is controlled by one to four transistors that can make the screen faster, brighter, more colorful than passive-matrix and capable of being viewed at different angles.

· 3-D Monitors describe an image that provides the perception of length. When 3-D images are made intereactive then user feel involved with the scene, and his experience is called virtual reality.

·  Printer prints information and data from the computer onto a paper. It can print documents in colour as well as in black and white.

· Plotter is a special kind of output channel, like a printer, that produces images on paper. They are mainly used to produce large drawings or images.

· Speaker Is an output device that receives sound in the form of  electric current. It needs a sound card connected to a CPU, that generates sound.

3.     CPU(Central Processing Unit) : CPU is considered as “Brain Of Computer”. It is responsible for all the manipulations and processing of the data provided to the computer. It is further categorized basically into two main components

·   Arithmetic Logical Unit (ALU)  performs both  arithmetical and logical operations. Arithmetic operations involves addition, subtractions, multiplications, division etc. and the logical operations involves AND, OR, NOT, NOR, NAND etc.

·    Control Unit (CU) is an important part that instructs, maintains and controls the flow of information but does not store the data. It tells the memory, ALU and I/O devices that how they have to respond to the program’s instruction.

4.     Memory Unit: Thus unit stores the data and instructions, intermediate results or the processed data and thus, provides the relevant information whenever required by the other units of computer.