Lesson Notes By Weeks and Term - Junior Secondary School 1

SUBJECT: ICT

CLASS:  JSS 1

DATE:

TERM: 1st TERM

 
WEEK 4-5

TOPIC: CONCEPT OF COMPUTER

Definition of computer

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

FOR WEEK 4 & 5

PARTS OF 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 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. 

•  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 mouse also have a wheel between the two buttons, which allows you to scroll smoothly through screens of information.   

1. 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.

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

• 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.

1. Modem: A modem is 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 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.  Input device is divided into to types, these are: 

1. Manual input device
2. Automatic input device 

Examples of input device are: 

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

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

Examples of output device 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, 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 control unit. It takes care of step by step processing of all operations inside the computer

        WEEK 6

DATA AND INFORMATION

DATA

Definition 

Data are raw facts and figures collected which cannot be used instantly for any decision making until it is processed. Data is also defined as unprocessed information. Examples of data are alphabets, numbers, or symbols.

TYPES OF DATA

1. Numerical data: These are figures or numbers .Examples are  5, 6 and 10
2. Alphabetic data: These are letters, names and places. Examples are A-Z, female.Adenike.
3. Alpha-numeric data: These are combination of alphabets and numbers; Example. Home Address: 8, Babayemi Street, Agege Lagos state.
4. Audio data: These are voice data. 
5. Graphic data or visual data or video data: These can be pictures, images, diagrams and camera image.

SOURCES OF DATA

Data can be obtained through the following sources:

1. Interview: Data can be obtained through oral interview
2. Observation: Data can be obtained through personal observation of things that happen around us.
3. Document analysis: Data can be obtained through reading and breaking down of

various records.

        INFORMATION   

Definition: 

Information can be defined processed, manipulated and organized data into meaningful and useful form.  Information = Data + process.

For example, in a school, data in form of term examination scores are processed for each student to obtain information in form of first or second term result for individual student

Secondly, in banking institution, withdrawals, interest, deposits, bank charges for each customer are usually processed to obtain individual customers’ statement of account.

QUALITIES OF GOOD INFORMATION

Good information must possess certain qualities to produce meaningful result for decision making. The qualities of good information are as follows:

• Relevant :It should be related to the matter in hand

• Accurate : It must be correct and free from errors

• Comprehensive: It must  complete and easy to understand

• Meaningful: It must be expressed in a language that the receiver will understand. 

• Timely: It must be available at the right time when the users need it.

• Reliability: It must be unfailing.

• Economical: Information must be less costly than the value it provides.

• Suitable: It should be right for the purpose or occasion in which it is being made.

CLASSIFICATION OF INFORMATION BASED ON THE FORM IN WHICH THE INFORMATION EXISTS

1. Written information: This is written down formation such as magazine, newspapers.
2. Oral information: This is communicated information by talking, speaking.
3. Visual information: This is communicated through pictures, charts, graphs and video.
4. Sensory information: This is communicated through the senses such as hearing, feeling, smelling.

CLASSIFICATION OF INFORMATION BASED ON THE TIME OF OCCURRENCE

1. Continuous information: e.g. inter-house sports competition.
2. Hourly information: e.g. Radio news.
3. Daily information : e.g. daily newspaper( Daily time, punch)
4. Termly information: e.g. student’s card.
5. Annual information: e.g. company’s annual report or budget.

DIFFERENCE BETWEEN DATA AND INFORMATION