Subject :

Computer Studies / Information Communication Technology ICT 

Class :

SS 1

Term :


Week :

Week 8

Reference Materials :  .


Instructional Materials :..

  • Computer Studies
  • Online Resources


Previous Knowledge :

The pupils have previous knowledge of


that was taught as a topic in their previous lesson

Behavioural Objectives :  At the end of the lesson, the pupils should be able to

  • Say the components of the computer system
  • Explain the classes of hardware.
  • Define software.
  • Highlight difference between system and application software





The computer system is made up of the following components:

– The Central Processing Unit (CPU)


– The Memory Unit


– The Input/Output (I/O) Devices


– The Storage Devices


1. What is the Central Processing Unit (CPU)?


2. What is the Memory Unit?


3. What are Input/Output (I/O) Devices?


4. What are Storage Devices?


5. How do these components work together to form a complete computer  system?

Types of Computer Wares 

A computer system consists of three main parts otherwise called components. They are :

  1. Hardware
  2. Software
  3. People ware



The computer hardware could be defined as the physical parts of the computer that we see, feel and handle. It consists of device for input, processing, storage, output and communications.

Hardware can be divided into two sections:

  1. System Unit
  2. The peripherals



Hardware is the physical parts of the computer system that you can see and touch. They are the components that make up the visible computer. It consists of devices for input, processing, storage, output and communications.

The basic parts of computer hardware can be divided into:

  1. System Unit
  2. Peripherals




1. What is hardware?


2. What is software?


3. What are the differences between hardware and software?


4. What are the different types of software?


5. What are the different types of hardware?


6. How do these components work together to form a complete computer system?



The CPU is the brain of computer system and it can subdivided into:

  1. Control Unit
  2. Arithmetic and Logic Unit
  3. Memory Unit



This is the unit of the computer system that fetches instructions from the main storage, interpret them and issue all the necessary signals to the components making up the system.



This part of the CPU is where all arithmetic operations are carried out  in the computer. This unit is also involved in decision making. Logic functions such as less than (<), equal (=), greater than (>) etc which are operations of comparisons are used for decision making.



The memory or primary storage unit is the place in the computer where the program and  the data are stored. The computer memory is divided into two namely:

  1. Random Access Memory (RAM)
  2. Read Only Memory (ROM)



The peripherals are devices outside the CPU but function under the control of the CPU e.g mouse, keyboard, printer etc.



  1. What are the components of the computer system?
  2. What are the classes of hardware?



Software is the set of instructions that is used to direct the computer hardware to perform its tasks. That is, it is a set of instructions that makes the users to do work and allow the computer to operate. Software is basically programs i.e another name for software is program.Program is the sequence of instructions given to computer to solve a given problems or accomplish a given task. There are two main classes of software which are:

  1. System software
  2. Application software



These are programs written by the manufacturer to control the smooth running of the computer.



These are programs written by programmers to instruct the computer to perform a particular task.



  1. What is software?
  2. What is the difference between system and application software?



These are people who make and use the computer. They range from professional users to operational users. A user could also be anyone who makes use of computer. Without people, the computer cannot work. There two main classes of people ware:

  1. Computer professionals.
  2. Computer users.



  1. Can the computer system work without people?
  2. Software is subdivided into…………and ………
  3. What are the three components of the system unit?
  4. Explain the function of each component of the CPU.



Peripherals are in three categories:

  1. Input Devices
  2. Output Devices
  3. Auxiliary Storage Devices



  1. What is the difference between input and  output device?
  2. Give four examples of auxiliary device.



Sizes of Microcomputer are:laptop, palmtop, handtop, desktop, tower etc.



  4. MOUSE



A computer is an electronic machine which accepts data as input, processes the data and gives out information under the control of stored programs. The information which the computer gives out is called OUTPUT.


There are three keywords to note in the definition:


This is the physical aspect of a computer known as computer hardware. It consists of electronic and electro-mechanical parts working together to process data.

  1. It accepts data (input).
  2. It processes data (processing).
  3. It supplies information (output).

A program is a set of instructions which tells the computer to perform a given task. A computer does not understand English or any of the Nigerian languages. Rather it has its own language called PROGRAM.



The microcomputer is divided into three main parts namely:

  1. Central Processing Unit (CPU)
  2. Monitor
  3. Keyboard



1. What is the main parts of a microcomputer?


-The Central Processing Unit (CPU)


-The Memory Unit


-The Input/Output (I/O) Devices


-The Storage Devices


2. What is the most important part of a computer system?


-The Central Processing Unit (CPU)


-The Memory Unit


-The Input/Output (I/O) Devices


-The Storage Devices


3. What is the least important part of a computer system?


-The Central Processing Unit (CPU)


-The Memory Unit


-The Input/Output (I/O) Devices


4. What is input device’s main purpose?


-To put information into the computer system


-To take information out of the computer system


5. What is an output device’s main purpose?


-To put information into the computer system


-To take information out of the computer system



We have learnt the definition of a computer, that is, computer is an electronic machine which accepts data as input, processes the data and gives out information under the control of stored programs. We also learnt that the computer is divided into three main parts which are Central Processing Unit, Monitor and Keyboard.



  1. Mention the three main parts of microcomputer.
  2. List the four types of computers according to size.
  3. What is microcomputer?
  4. State the difference between CPU and system unit.


Computer software (often called just software) is a set of instructions and associated documentation that tells a computer what to do or how to perform a task or it can mean all the software on a computer, including the applications and the operating system

It is also a set of instructions (programs) that commands the computer hardware what to do, how to do and as well as when to do. In other words, software is a set of programs, procedures, algorithms and its documentation. It is the driver of the hardware. Without the software, the computer becomes useless and an idle piece of metal. 

In contrast to hardware, software is intangible, meaning it ‘it cannot be touched’.

Software as a whole can be divided into a number of categories based on the types of work done by programs. The two primary software categories are;

  • This is a collection of computer software designed to operate the computer hardware and to provide and maintain a platform for running application software.
  • Systems software includes the programs that are dedicated to managing the computer itself, such as the operating system, file management utilities, and disk operating system (DOS) which control the workings of the computer.
  • More so, it can be defined as a collection of programs designed to operate, control, and extend the processing capabilities of the computer hardware. System software is generally prepared by the computer manufacturers. These software products comprise of programs written in low-level languages, which interact with the hardware at a very basic level. System software serves as the interface between the hardware and the end users.

Some examples of system software are Operating System, Compilers, Interpreter, Assemblers, etc.

Categories of System software includes:

  1. Operating systems : An operating system is a program that acts as an interface between the software and the computer hardware e.g windows o/s, Linus o/s, disk operating system, handroid o/s, symbian o/s, etc.
  2. Device drivers  : is a computer program that operates or controls a particular type of device that is attached to a computer e.g. scanner driver, printer drivers, network drivers, graphics driver, sound card drivers, etc.
  3. Utility software : designed to help analyze, configure, optimize or maintain a computer.It is used to support the computer infrastructure in contrast to application software, which is aimed at directly performing tasks that benefit ordinary users. Examples are: anti-virus, clipboard managers, disk checkers, disc cleaner, disk defragmenters, file managers, etc
  4. Translators  : is a software that converts high level language(human language or source code) to machine language

An application program (app or application for short) is a computer program designed to perform a group of coordinated functions, tasks, or activities for the benefit of the user.

also known as software application, application or app, consists of programs that instruct the computer to accomplish specific tasks for the user, such as word processing, operating a spreadsheet, managing accounts in inventories, record keeping, or playing a video game. These programs, called applications, are run only when they are needed. The number of available applications is as great as the number of different uses of computers. Some examples of this category of software includes;


  • Accounting software e.g Peachtree Complete Accounting
  • Computer-aided design e.g. Corel Draw
  • Databases e.g. Microsoft access
  • Decision making software e.g. Microsoft project
  • Educational software e.g. Microsoft Encarta
  • Image editing e.g. Adobe photo-shop
  • Mathematical software e.g.  SAGE
  • Word processor e.g. Microsoft word
  • Spreadsheets e.g. Microsoft excel
  • Media players and database applications



(i)  Can run independently of the application software (i)  It cannot run without the presence of the system software
(ii)  It gets installed when the operating system is installed on the computer  (ii)  It is installed according to the requirements of the user
(iii) They are programs that run and control the hardware units of the system (iii)  They are programs designed to meet specific needs of users
(iv) It provides a platform for running the application software  (iv)  It helps the user to perform single or 

multiple tasks

(v)  Some examples of system software are computer operating systems like Windows XP, Linux, MacOs and Ubuntu (v)  Some examples of application software are Microsoft Word, Accounting software like Microsoft Excel and Microsoft Access
(vi) They are intricately(carefully) programmed by system programmers  (vi)  They are programmed by applications programmers.



The following are the major characteristics of a computer, depending on their types and application:

  • Speed
    A computer works at amazing speed. It can carry out instructions at a very high speed because it uses an electronic signal which runs at the speed of light. It can perform in a few seconds the amount of work that a human being can do in an entire year – if he works day and night and does else.

    Some calculations that would have taken hours and days to complete otherwise, can be completed in a few seconds using the computer. The speed of computer is calculated in MHz, that is one million instructions per second.

    The accuracy of a computer is consistently high. The degree of accuracy depends on the instructions and the type of processor. It performs operations at fast rate gives the result of division of any number up to 10 decimal points without errors such that the accuracy is beyond expectation. Since it is programmed, the result can only be wrong if the input is wrong.

    Versatility is one of the most wonderful things about computer. Multi-processing features of computer makes it quiet versatile in nature. One moment, it is preparing the results of particular examination, the next moment it is busy preparing electricity bills, and in between it may be helping an office secretary to trace an important letter in seconds.

    It can perform different types of tasks with same ease. All that is required to change its talent is to slip in a new program into it. Briefly, a computer is capable of performing almost any task provided that the task can be reduced to a series of logical steps.

     • Reliability 
     Computer provide very high speed accompanied by an equality high level for reliability. Thus computers never make mistakes of their own accord.

     • High Storage and Retrieval Capacity
    A computer can store and recall any amount of information because of its secondary storage capability. Every piece of information can be retain as long as desired by the user and it can be recalled information almost instantaneously. Even after several years, the information recalled will be as accurate as on the day when it was fed to the computer.

     • Diligence 
    The computer is a machine, does not suffer from the human traits of tiredness. Nor does it loses concentration even after working continuously for a long time.

    This characteristics is especially useful for those jobs where same tasks is done again and again. It can perform long and complex calculations with same speed and accuracy from the start till the end.

     • Storage
    The computers have a lot of a storage devices which can store a tremendous amount of data. Data storage is essential function of the computer. Secondary storage devices like floppy disk can store a large amount of data permanently.

.  Automation

Once the instructions are fed into computer it works automatically without any human intervention until the completion of execution of program until it meets logical instructions to terminate the job.



  1. …… an electronic machine which accepts data as input, processes data and gives out information.  A. Television    B.  Computer   C.    Photocopier D.  None
  2. A computer accepts data as……..A.  input  B.  output   C.  processing  D. store
  3. The microcomputer is divided into ……  A.  3   B.   4    C.  5 D.  9
  4. The information which the computer gives is called ……..   A. input   B.  output   C.   processing   D. None
  5. The language the computer understands is called……..  A.   English    B.  programs    C.  French   D.  all languages



  1. What is a program?
  2. Mention the main parts of a computer.
  3. What is an input device?
  4.  What is an output device? 
  5. What is a processor? 
  6. What is a storage device? 
  7.  What is software? 
  8.  What is a system unit? 
  9.  How is a computer different from a calculator?


The topic is presented step by step


Step 1:

The class teacher revises the previous topics


Step 2.

He introduces the new topic


Step 3:

The class teacher allows the pupils to give their own examples and he corrects them when the needs arise


Write out five multiple questions with one correct answer and one wrong answer that are related to the topic


Conclusion :


The class teacher wraps up or conclude the lesson by giving out short note to summarize the topic that he or she has just taught.

The class teacher also goes round to make sure that the notes are well copied or well written. He or she does the necessary corrections when the need arises.