Computer System

A computer system is the integration of physical entities called hardware and non-physical entities called software. The combination of computer hardware and software that can perform a specified task is called computer system. The hardware components include input devices, processor and output devices whereas the software components include the operating system, programs and computer data. Thus, a computer system is a set of integrated devices that input, process, output and store data and information.

 

There are two sub-system of computer system. They are:

1.      Software

2.      Hardware

 

Software: Software is the set of programs or computer codes that helps to run the computer hardware by providing instructions. Operating System and computer programs are the software that are important part of computer system.

 

Hardware: All the physical components of computer system are called computer hardware. They are the input/output devices and the internal electronic circuits. The hardware components are classified into four main units as:

1.      Input Unit.

2.      Output Unit.

3.      Storage Unit.

4.      Central Processing Unit (CPU)

Input Unit

Input unit is the computer hardware that helps to enter the computer programs and data into the computer system. The devices that are used to fed data and instructions to the computer system is called input devices. They are the medium for transferring the data from the user to the computer system.

Some example of input devices are listed below:

1.      Keyboard

2.      Mouse

3.      Digital camera

4.      Joystick

5.      Scanner

6.      Microphone

7.      Touch pad

8.      Light pen

 

Keyboard

keyboard is the most commonly used input device. It is very important input device that helps to enter data and instructions into the computer system by pressing the keys on the keyboard. There are several keys on the keyboard that helps to enter the desired instructions as well as data into the computer system.

 

Mouse

Mouse is a small pointing device that helps to give instructions to the computer by selecting menus or items on the computer screen. The mouse pointer moves according to the movement of the mouse and the pointer is called cursor. The functions of the mouse are click, double click, right click, drag and drop.

 

Digital Camera

Digital camera is an input device that captures pictures of an object and transfer them to computer in the form of digital image. The memory of the camera can be used to transfer the image to computer.

 

Joystick

Joystick is an input device similar to Mouse that helps to play games. It moves in all the directions and controls the movement of a pointer.

 

Scanner

It is an input device that is used to scan documents or image. Scanned documents or images are convert it into digital form with the help of this device.

 

Microphone

Microphone is an input device that helps to convert the voice into digital form. It inputs the voice and transfer it to the computer or other digital devices. 

 

Touchpad

Touchpad is a small touch sensitive pad that acts as an input device in the laptop. You can move the mouse cursor by moving your fingers on this touchpad and perform all the activities that can be performed with the mouse.

 

Light pen

A light pen is a pointing device that utilizes a light sensitive detector to select object on a display screen. It works like a mouse to select the object on the screen.

 

Output Unit

The output unit helps to give output. The device that gives output is called output device. It displays the result of processing or prints the output on the paper. The output may be in the form of image, text, audio, video, etc. On the basis of output there are two types of output devices.

 

Softcopy Output device

The output device helps to display softcopy output such as text, audio, image is known as softcopy output device. Monitor, speaker are the examples of software output device.

 

Monitor

Monitor is a softcopy output device that displays the result of processing. Monitor is called a softcopy output device because it displays softcopy output temporarily on the screen. LCD, LED, CRT are the types of monitor.

 

Speaker

Speaker is an output device that gives audio output. It is also a softcopy output device.

 

Hardcopy Output device

The device that helps to give hardcopy output on the paper is called output device. Printer, plotter is an example of hard copy output device.

 

Printer

Printer is an output device that prints the output information on the paper. It is called a hardcopy output device because it gives permanent output by printing the output on the paper. Inkjet printer, Dot matrix Printer, Laser printer are the types of printer.

 

CPU Central Processing Unit

CPU is the main processing device of the computer system that processes the input data and convert it into the meaningful information that is displayed on the monitor in the form of output.

It controls and manage all the activities of the computer so it is also called the brain of the computer. CPU has three main units as control unit, arithmetic and logic unit, and memory unit.

 

Control Unit (CU): Control Unit control and manage all the activities of computer. It coordinates all the units of a computer.

 

Arithmetic and Logic Unit (ALU): ALU performs all the arithmetical and logical calculations such as addition, subtraction, multiplication and division. Besides, it performs logical calculations like comparing, selecting, etc.

 

Memory Unit: Memory unit stores the computer data and instructions. It stores the output data for displaying on the monitor.