Concept Of Computers JSS1 Computer Studies Lesson Note

Definition of computer

A computer can be defined as an electronic device that accepts data as an input, processes it, stores it, and gives out information as the output.

PARTS OF THE COMPUTER SYSTEM

A computer is a system of many parts working together. The physical parts, which you can see and touch, are collectively called hardware while software refers to the instructions, or programs, that tell the hardware what to do.

The following are parts of the computer system. These include: 

•             System unit (CPU) 
•             Monitor
•             Mouse
•             Keyboard
•             Printer
•             Speaker
•             Modem

1.         System unit: The system unit is the core of a computer system. It is a rectangular box placed on or underneath your desk. The most important of these components is the central processing unit (CPU), or microprocessor, which acts as the “brain” of your computer. Another component is random access memory (RAM), which temporarily stores information that the CPU uses while the computer is on. The information stored in RAM is erased when the computer is turned off.
2. Monitor: A monitor displays information in visual form, using text and graphics. The portion of the monitor that displays the information is called the screen.  There are two basic types of monitors: CRT (cathode ray tube) monitors and the newer LCD (liquid crystal display) monitors.  
3.           Mouse: A mouse is a small device used to point to and select items on your computer screen. A mouse usually has two buttons: A primary button (usually the left button) and a secondary button. Many mice also have a wheel between the two buttons, which allows you to scroll smoothly through screens of information.
4.         Keyboard: A keyboard is used mainly for typing text into your computer. It has keys for letters and numbers, but it also has special keys:

The function keys: found on the top row, perform different functions depending on where they are used.

The numeric keypad: These key located on the right side of most keyboards, allows you to enter numbers quickly.

The navigation keys: These arrow keys, allow you to move your position within a document or webpage. 

5             Printer: A printer is a part of a computer system that transfers data from a computer onto paper. It allows you to print e-mails, cards, invitations, announcements, and other materials.  The two main types of printers are inkjet printers and laser printers. 

6           Speakers: Speakers are used to play sound. They can be built into the system unit or connected with cables. Speakers allow you to listen to music and hear sound effects from your computer. 

7         Modem: A modem is an internet device that sends and receives computer information over a telephone line or high-speed cable. Modems are sometimes built into the system unit, but higher-speed modems are usually separate components.

COMPONENTS OF COMPUTER SYSTEM UNIT

There are two categories of components of a computer system unit. These are 

1.         Input device
2.         Output device
3.         Storage device
4.         Arithmetic Logic Unit

INPUT DEVICE: This device is used for entering data and programs into the computer system by the user for processing.  The input device is divided into two types, these are: 

1.         Manual input device
2.         Automatic input device 

Examples of input devices are: 

1.         keyboard 
2.         mouse 
3.         joystick 
4.         graphics tablet 
5.         trackball 
6.         touchpad 
7.         touch screen 
8.         microphone 
9.         sensor
10. Scanner
11. Webcam

Output device: Output devices are pieces of hardware that send usable processed information out of the computer. 

Examples of output devices are as follows

1.         printer 
2.         monitor 
3.         touch screen 
4.         plotter 
5.         speakers 
6.         headphones 
7.         Media projector

Storage device: The storage device is used for storing data and instructions before and after processing. This includes devices such as hard disk drives and compact disk drives.

Arithmetic Logic Unit:  It performs arithmetic functions like addition, subtraction, multiplication, and division, and also logical operations like greater than, less than, and equal to, are carried out.

Control Unit: Controlling of all operations like input, processing, and output are performed by the control unit. It takes care of step by step processing of all operations inside the computer