1ST TERM JSS2 COMPUTER Scheme of Work and Note

FIRST TERM E-LEARNING NOTE

SUBJECT: COMPUTER STUDIES  CLASS: JSS2

SCHEME OF WORK

WEEK TOPIC

1. Classification of Computer
2. Component of a Computer System
3. Hardware
4. Software
5. Peopleware
6. Operating System
7. Function of operating system
8. Number Bases
9. Conversion of Number Bases
10. Unit of Storage in Computer

    References: A handbook on Computer Studies for Schools and Colleges by Niyi Adekolegan; Computer Studies for Junior Secondary Schools by M. Tuttuh-Adegun, Abubakar Nuhu

    Also Read:

    • 1ST TERM JSS2 BASIC SCIENCE Scheme of Work and Note
    • 1ST TERM JSS2 BASIC TECHNOLOGY Scheme of Work and Note

WEEK ONE

TOPIC: CLASSIFICATION OF COMPUTERS

CLASSIFICATION OF COMPUTERS BY GENERATION

1^st Generation Computer

These sets of Computers were built between 1940s and 1950s. They used electronic valves (or vacuum tubes) for their circuit e.g. Leo Mark III, UNIVAC, EDVAC, EDSAC etc

2^nd Generation Computer

These set of computers existed between 1950s and 1960s. They used transistors in place of valves. They were smaller in size but faster in operation compared to the 1^st generation computers.

3^rd Generation Computer

These set of computers employed the use of integrated circuits (IC) instead of the use of transistor used during second generation. These set of computers were created between 1960s and 1970s.

4^th Generation Computer

This generation of electronic computers came into existence from 1970s to 1980s. These computers made use of Large Scale Integrated Circuit (LSIC). This marked the era of micro processor with input and output devices connected to the system unit.

5^th Generation Computer

These are the present day computers. These computers can learn, take decisions and solve problems without human intervention. These computers make use of Artificial Intelligence and become what we call an Expert System which can make decisions on its own and solve problems like a human expert in a particular field. These computers also make use of Very Large Scale Integrated Circuit (VLSIC).

EVALUATION

1. How many generations of computer exist?
2. List and explain each generation of the computer.

    

CLASSIFICATION OF COMPUTER BY SIZE AND CAPACITY

1. MICROCOMPUTER
   

This is the smallest and most popular class of computers. Microcomputers are also called personal computers (PC). They are accessible, relatively cheap and interactive. Examples are Desktop Computers, Laptop Computers, Notebook Computers, Palmtop and Workstation.

1. MINICOMPUTER
   

This is a medium sized general purpose computer. It is a multi – user i.e. it allows many users at once and has the ability to perform many tasks simultaneously. Examples are PDP 11, IBM 800 etc.

1. MAINFRAME COMPUTER
   

These are multi – user and multi – tasking general purpose computers. They have large storage capacity and they are expensive. They are used mostly by large organizations such as Banks, Universities, Central Bank, National population Commission etc. Examples are CDC 6600, IBM ES000 series etc.

1. SUPER COMPUTER
   

This can be seen as a technological improvement on mainframe computers. It is used in the scientific environment such as for space studies and weather forecast. They have higher processing powers and large storage capacities. Examples are Cray1, Cray2 etc.

EVALUATION

1. List and explain the classification of computer by size and capacity.

2. List areas where mainframe computer can be used.

CLASSIFICATION OF COMPUTER BY TYPE AND PURPOSE

1. CLASSIFICATION OF COMPUTER BY TYPE
   

• DIGITAL COMPUTER
• ANALOGUE COMPUTER
• HYBRID COMPUTER

DIGITAL COMPUTER:

This is the most common type of computer today. It measures physical quantities by counting. Examples are calculators, digital wrist watches, digital fuel dispenser etc.

ANALOGUE COMPUTER:

This is a computer created to measure and process continuous data such as speed, temperature, heartbeat etc Examples of such computers are speedometer, thermometer etc.

HYBRID COMPUTER:

This type of computer combines the features of digital and analogue computers together. It is a combination of digital and analogue computer. Examples are fuel dispensing machine etc.

EVALUATION

1. List the classification of computers according to type
2. Explain the difference between the classifications of computer according to type.

1. CLASSIFICATION OF COMPUTER BY PURPOSE
   

Classification of computer according to purpose can be grouped into 2 namely:

• General purpose computers
• Special purpose computers

SPECIAL PURPOSE COMPUTERS

These are computers designed solely to solve a restricted class of problem e.g. computer for medical diagnosis, weapon guidance, traffic control, weather study and forecast, control of airplanes and production control of refinery and guidance etc.

GENERAL PURPOSE COMPUTERS

These are computers designed solely to solve a vast variety of problems e.g. it can be used for Word-processing and at the same time used for graphics, database, spreadsheet etc. Examples Dell, HP etc.

GENERAL EVALUATION/REVISIONAL QUESTIONS

1. Explain the following:

(a) General Purpose Computers

(b) Special Purpose Computers

2. Mention areas where special purpose computers may be used.

3. What is VLI?

4. Differentiate between digital and analogue computers.

READING ASSIGNMENT

Computer studies for Junior Secondary Schools 2, p1- p5

WEEKEND ASSIGNMENT

Instruction: Choose the correct option from the ones lettered A to D

1. How many classifications of computers do we have? (a) 4  (b) 3 (c) 4 (d) 5
2. The Generation of Computer that uses Artificial Intelligence is ………………
   1. Fifth Generation (b) Third Generation  (c) Second Generation (d) First Generation  
3. …………… is the smallest and the most popular class of Computer
   1. Microcomputer   (b) Mainframe Computer (c) Super Computer (d) Mini Computer
4. What type of computer combines the features of digital and analogue computers together?
   1. Microcomputer  (b) Hybrid Computer  (c) Mini Computer (d) Mini Computer
5. Computers designed solely to solve a restricted class of problem is called …………… computer
   1. Special Purpose (b) Digital (c) Analogue (d) General Purpose

SECTION B

1.  List the classification of computers according to type.

2.  Explain the difference between the classifications of computer according to type.

WEEK TWO

TOPIC: COMPONENT OF A COMPUTER SYSTEM

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

1. Hardware
2. Software
3. Peopleware

HARDWARE COMPONENT

The computer Hardware could be defined as the physical parts of the computer that we can see, feel and handle. It consists of device for input, processing, storage, output and communications. Hardware can be divided into two sections:

1. The System unit
2. The Peripherals

The peripherals are devices outside the central processing unit (CPU) but function under the control of the CPU. E.g. Mouse, Keyboard, Printer etc

EVALUATION

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

SOFTWARE COMPONENT

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 sequence of instructions given to computer to solve a given problem or accomplish a given task. There are two main classes of software which are:

1. System Software
2. Application Software

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

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

EVALUATION

1. What is software?
2. What is the difference between System and Application Software?

PEOPLEWARE

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 are two main classes of peopleware:

1. Computer Professionals
2. Computer Users

GENERAL EVALUATION/REVISION QUESTIONS

1. Explain the term computer system.
2. List three components of a computer system.
3. Explain the terms: (a) System software (b) Application software

READING ASSIGNMENT

Computer studies for Junior Secondary Schools 2, p12.

WEEKEND ASSIGNMENT

Instruction: Choose the correct option from the ones lettered A to D

1. A computer system consists of ……………. main parts (a) 3 (b) 2 (c) 4 (d) 5
   
2. The physical part of the computer that we can see, feel and handle is called ……………….
   1. Hardware  (b) Software  (c) Peopleware (d) Systemware
3. ………………. are devices outside the central processing unit (CPU) but function under the control of the CPU (a) Peripheral (b) Hardware  (c) Software (d) CPU
4. ………………… are programs written by the manufacturer to control the smooth running of the computer (a) System Software  (b) Application Software (c) Peripherals (d) Operating system
5. Computer Professional and Computer ……………. are the two main classes of peopleware
   1. Analyst  (b) User (c) Software (d) Hardware

SECTION B

1. What is software?
2. What is the difference between System and Application Software?

    

    

WEEK THREE

TOPIC: HARDWARE

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

SYSTEM UNIT

The system unit houses the CPU and the Memory Unit and the CPU can be subdivided into:

1. Control Unit
2. Arithmetic and Logic Unit
3. Registers
4. Internal Bus

CONTROL 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.

ARITHMETIC AND LOGIC UNIT: 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 to (=), greater than (>) etc which are operations of comparisons are used for decision making.

REGISTERS: The registers are temporary storage areas that hold data, keep track of instructions, and the hold the location and the result of these operations.

INTERNAL BUS: Is the last segment of the CPU which is a network of communication lines that connects the CPU parts together and to all other parts of the computer hardware.

MEMORY UNIT: 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)

EVALUATION

1. What are the three components of the CPU?
2. Explain the function of each component of the CPU.

PERIPHERALS

The general name for all input and output devices are called Computer Peripherals. Peripherals are in three categories

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

INPUT DEVICE: These are the medium through which we can send data into the computer system for processing. Input devices help to convey information from human readable form to electrical/digital form which the machine can interpret and process with the CPU. Examples of input devices are keyboard, mouse, joystick, scanner, light pen etc.

OUTPUT DEVICE: Output devices are the devices that are used to send data out of the computer. Output devices convert machine – readable information into people – readable form. That is, they are used for obtaining result of processed data from the central processing unit. The following are example of output devices:

1. Monitor
2. Printer
3. Plotter
4. Speaker

AUXILIARY / SECONDARY STORAGE DEVICES: The auxiliary storage devices are additional memory or external storage device. It is otherwise called BACK UP storage devices. This device holds large amount of data or information. Examples are floppy disks, CD-ROM, Zip disk, Flash disk etc

GENEAL EVALUATION/REVISIONAL QUESTIONS

1. What is the difference between input and output device?
2. Give four example of auxiliary storage device.
3. What is difference between auxiliary and internal storage?
4. Give five examples of secondary storage devices.

READING ASSIGNMENT

A hand book of computers for Colleges and Schools, p31.

WEEKEND ASSIGNMENT

Instruction: Choose the correct option from the ones lettered A to D

1. Scanner is an example of ……………….
   1. Output device  (b) Input device  (c) Storage device (d) System device
2. The general name for all input and output devices are called …………………….
   1. Hardware (b) Peripheral  (c) Software   (d) Peopleware
3. The part of the CPU where all arithmetic operations are carried out is called ………………..
   1. Control unit (b) Arithmetic and Logic Unit  (c) Memory Unit (d) Internal bus
4. These are Output devices except …………………
   1. Monitor (b) Speaker (c) Keyboard (d) Light pen
5. ……………….. is the brain of the computer
   1. Scanner (b) C.P.U (c) Printer (d) CUP

       

SECTION B

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

WEEK FOUR

TOPIC: SOFTWARE

Computer Software or simply
software is the set of instructions that are used to direct the computer hardware to perform its tasks. That is, it is a set of instructions that make the users to do work and allow the computers to operate.

TYPES OF SOFTWARE

There are two main classes of Software

1. System Software
2. Application Software

SYSTEM SOFTWARE

System Software is a collection of program (written by the computer Manufacturer) that are directly responsible for ensuring utilization of the hardware components of a computer. It can be thought of as “background software”. It is designed to make the use of computer easy. Computer manufacturer usually write system software.

TYPES OF SYSTEM SOFTWARE

1. Operating system
2. Language Translator/processors
3. Utility programs
4. Device Drivers

EVALUATION

1. What is software?
2. Mention the classes of software.

APPLICATION SOFTWARE

This is a program written by computer users to perform particular tasks or set of tasks of solving personal problems. This software has no direct effect on the utilization of the computer resources. There are two types of application software:

1. Application Packages
2. Application Programs

EXAMPLES OF SYSTEM SOFTWARE

1. Operating System – DOS, Windows, UNIX, LINUX
2. Language Translator – Assembler, Interpreter, Compiler
3. Utility Program – File Conversions, File Copy, Back up Data etc
4. Device Driver – Printer Driver, Sound Driver etc

EXAMPLES OF APPLICATION SOFTWARE

1. Browsers :– Internet Explorer, Mozilla Firefox etc
2. Word-processor : – Ms-Word, Word Perfect etc
3. Spreadsheet :– Ms-Excel, Lotus 1-2-3 etc
4. Database Management System (DBMS): – Ms-Access, Oracle etc

GENERAL EVALUATION/REVISIONAL QUESTIONS

1. What is Software?
2. Give two types of software?
3. Give two examples of Device driver
4. What is application software?

READING ASSIGNMENT

Computer studies for Junior Secondary Schools 2 p21-22.

WEEKEND ASSIGNMENT

1. Interpreter is an example of ……………..
   1. Operating system  (b) Application package (c) Translator (d) Device Driver
2. ……… is directly responsible for ensuring utilization of the hardware components of a computer
   1. Application Software  (b) Hardware  (c) System Software (d) Translator
3. The program written by computer users to perform particular tasks or set of tasks of solving personal problems is called ………………
   1. Peripherals  (b) System Software  (c) Application Software (d) Translator
4. Another name for Software is ………………

    

   1. Spreadsheet (b) Program (c) Hardware (d) Human
5. There are …………… types of application software
   1. 2  (b) 3 (c) 4 (d) 5

SECTION B

1. What is Software?

2. Give two of types of software?

WEEK FIVE

TOPIC: PEOPLEWARE

The human aspect of computer is called Peopleware or Humanware. Peopleware are the people working with the computer. Without people, the computer cannot work. There are two main classes of peopleware

1. Computer Professionals
2. Computer Users

    

1. COMPUTER PROFESSIONALS
   

These computer professionals are those who have undergone one form of formal computer training or the other. Such formal training include certificates, diploma and degree programmes in computing. These categories of people are in the development, maintenance and the use of computer system. Various categories are computers professional which includes: Computer Manager, system analyst, programmers, computer educators, computer engineers, data entry operator etc

COMPUTER MANAGER

The computer manager has the overall responsibility for the computer department. He ensures that the computer installation runs efficiently satisfying the computing needs of the organization, which he services.

THE SYSTEM ANALYST

The system analyst looks at the details of existing systems and the design of computer based systems. The system analyst also implements and reviews the new system design of computer based systems.

PROGRAMMER

The programmer encodes the procedures detailed by the system analyst in a programming language. The programmer must be able to reason logically and clearly.

COMPUTER EDUCATOR

Computer Educator refers to people that teach computing at various levels varying from university down to primary school level.

COMPUTER ENGINEER

Computer Engineer and technician are people that install, maintain and repair the computer.

COMPUTER OPERATOR

These are people that handle and operate the hardware in the computer room using available software.

EVALUATION

1. What is Peopleware?
2. Give FOUR examples of Computer Professionals.

1. COMPUTER USER

The computer users are those in other professions who make use of the computer to do their jobs. They are called end – users e.g. Doctors, Bankers, Engineer etc. There are 3 categories of computer users namely:

1. Experts
2. Casuals
3. End Users

GENERAL EVALUATION/REVISIONAL QUESTIONS

1. What is the difference between a Computer Professional and a Computer User?
2. List THREE categories of computer users.
3. Who is a Computer Manager?
4. Give two examples of expert users.

READING ASSIGNMENT

A handbook on Computer Studies for Schools and Colleges

WEEKEND ASSIGNMENT

Instruction: Choose the correct option from the ones lettered A to D

1. The human aspect of computer is called ……………………
   1. Software (b) Hardware (c) System (d) Peopleware
2. Another name for End User is ………………..
   1. Computer professional  (b) Analyst  (c) Computer Manager (d) Computer User
3. ………………. are people that teach computing at various levels
   1. Computer Engineer   (b) Computer Analyst  (c) Computer Operator (d) Computer Educator
4. ………………. takes the overall responsibility for the computer department
   1. Computer Engineer   (b) Computer Educator  (c) Computer User (d) Computer Manager
5. The person that writes programs is called …………………
   1. System Analyst (b) Expert  (c) Peopleware (d) Programmer  

    

SECTION B

1. What is the difference between a Computer Professional and a Computer User?
2. List THREE categories of computer users.

WEEK SIX

TOPIC: OPERATING SYSTEM

What is Operating System?

An operating system can be defined as the collection of programs that control the overall operations of the a computer It is the master control program that runs the computer system. Examples of Operating System are (1)DOS (2) WINDOWS (3) LINUX (4) XENIX (5) OS/2

EVALUATION

1. What is Operating System?
2. Give FOUR examples of Operating System

TYPES OF OPERATING SYSTEM

There are different types of operating system as specified by their operational performance. The most commonly used operating systems are:

1. Single user operating system
2. Multi user operating system
3. Networking operating system

SINGLE USER OPERATING SYSTEM

The operating system allows only a single task to be performed at a time. It allows a single user to operate the machine at a time in an interactive mode and allows one user program to be in the main memory at a time. Examples of a single user operating system include MS-DOS, PC-DOS Windows XP etc.

MULTI – USER OPERATING SYSTEM

Multi – user operating system permits the execution of more than one task at a time. It shares the system resources to more than one user by connecting the individual users on the system. Examples are Unix, Zenix, OS/2 etc.

NETWORKING OPERATING SYSTEM

This operating system is used in network environment where users from different locations can interconnect computers connected to a large network such as WAN & INTERNET. Examples of a networking operating system include Windows NT, Windows Server 2003, Novel Netware etc

EVALUATION

1. Mention three types of Operating System.
2. What is the difference between the three types of Operating System?

KINDS OF OPERATING SYSTEM

DISK OPERATING SYSTEM

Disk Operating System is a command based operating system which can be located in the computer temporary memory called RAM. It allows the various parts of the computer to communicate with one another. It allows the computer users to copy files, format disk and print etc Examples of DOS are: MS-DOS (Microsoft Disk operating System), PC-DOS etc .

WINDOWS OPERATING SYSTEM

A windows operating system is a graphical user interface that enables you to communicate with your computer through ICONS, MENU, DIALOG BOX and application programs. Windows operating system is the major part of the system software that controls the interface between the computer and user. It communicates with the C.P.U. and gives result on the screen. The different versions of window are as follows Windows 95, Windows 98, Windows 2000, Windows Millennium and Windows XP.

GENERAL EVALUATION/REVISIONAL QUESTIONS

1. What is Disk Operating System?
2. List FOUR examples of Windows Operating System.
3. In a tabular form, differentiate between Disk Operating System and Windows Operating System
4. What is GUI?

READING ASSIGNMENT

A hand book on computers for Schools and Colleges, p39.

WEEKEND ASSIGNMENT

Instruction: Choose the correct option from the ones lettered A to D

1. ………… is the collection of program which controls the overall operations of a computer.
   1. Operating System (b) DOS (c) Windows (d) PC-DOS
2. One of the following is NOT an example of operating system
   1. MS-Word (b) Linux (c) Zenix (d) Windows XP
3. Operating System used in network environment is called ………………..Operating System
   1. Networking (b) Multi-User (c) Single User (d) Command-based
4. What operating system allows only a single task to be performed at a time?
   1. Single User (b) Multi-User (c) Networking (d) windows-based
5. What operating system uses a graphical user interface (GUI)?

(a) Windows (b) DOS (c) Linux (d)Unix

SECTION B

1. What is Disk Operating System?
2. List FOUR examples of Windows Operating System.

WEEK SEVEN

TOPIC: FUNCTIONS OF OPERATING SYSTEM

The general functions of the operating system include the following among others:

1. It helps in loading and scheduling of programs.
2. It protects software, hardware and data from improper use.
3. It manages hardware resources.
4. It performs the loading of program from external memory to the main memory.
5. It provides error correction routine.
6. It makes communication possible between the users and computer system.
7. It passes control from one job to another in a multi programming environment.
8. It handles interrupt and malfunctioning.

GENERAL EVALUATION / REVISIONAL QUESTIONS

1. Mention three protections offered by an operating system.
2. What does an operating system handle?
3. Loading of program is performed from where?
4. List the four functions of an operating system.

READING ASSIGNMENT

A hand book on computer studies for Schools and Colleges, p38

WEEKEND ASSIGNMENT

Instruction: Choose the correct option from the ones lettered A to D

1. The collection of programs that control overall operations of a computer is known as …………

   (a) DOS  (b) Operating system  (c) Windows  (d) Software

2. The operating system helps in loading and scheduling of ………………………….

   (a) Hardware  (b) Programs  (c) Output  (d) Input

3. ……………… manages hardware resources (a) Output (b) Operating system

   (c) Application software (d) Input

4. Operating system performs the loading of program from ………… memory to the main memory

   (a) Internal  (b) External  (c) Surface  (d) Registers

5. Operating system handles …………….. and malfunctioning (a) Resources  (b) Interrupt

   (c) Software  (d) Hardware

SECTION B

1. List FIVE functions of the operating system.

2. Operating system handles ………. …and ………….

WEEK EIGHT

TOPIC: NUMBER BASES

To effectively use the computer, it is therefore necessary to know how data is represented and communicated to it. There are different ways of representing data in the number system, namely:

1. Decimal System
2. Binary System
3. Octal System
4. Hexadecimal Number System

DECIMAL NUMBER SYSTEM

The Decimal Number System is numbers in everyday use. They are also denary number or numbers in base 10. Any denary number will contain any of the 10 symbols i.e. “0, 1, 2, 3, 4, 5, 6, 7, 8, 9,” where (n<10)

EVALUATION

1. List the different ways of representing data
2. Explain Decimal Number System

BINARY NUMBER SYSTEM

The binary system is a system of numbers, which has two as its base. The digits in base two are 0 and 1. Computer is made on the mechanism of a two – way device system that is a system which can make a decision that has two alternatives like:

1. True or False Statement
2. Yes or No
3. Switch ON or OFF in electrical circuit etc

EVALUATION

1. What is Binary Number System?
2. How many digits make up the binary number system?

OCTAL NUMBERS SYSTEM

The Octal Number System has a based or radix of 8. Eight different symbols are used to represent octal numbers. They are 0, 1, 2, 3, 4, 5, 6, and 7. Generally, it could be expressed as (N<8) which implies 0, 1, 2,…….n-1.

EVALUATION

1. What is Octal Number System?
2. How many digits make up the octal number system?

HEXADECIMAL NUMBER SYSTEM

The hexadecimal Number System has a base or radix of 16. Sixteen different symbols are used to represent hexadecimal Numbers. They are 0,1,2,3,4,5,6,7,8,9,A,B,C,D,E,F.

GENERAL EVALUATION/REVISION QUESTIONS

1. Write out the symbols used to represent Hexadecimal Number System
2. What are the symbols used for Octal and Binary Numbers System
3. What is Octal Number system?
4. How many digits make up the hexadecimal number system?

READING ASSIGNMENT

A hand book on Computers for Schools and Colleges, p51.

WEEKEND ASSIGNMENT

Instruction: Choose the correct option from the ones lettered A to D

1. Decimal Number is also called ……………….. numbers
   
   1. Binary  (b) Octal  (c) Denary   (d) Hexadecimal
      
2. Binary Number is in Base ………
   
   1. 4 (b) 3 (c) 2  (d) 16
      
3. The Octal Number System has a radix of ………….
   
   1. 2 (b) 10 (c) 16  (d) 8
      
4. In the Hexadecimal Number System, number 16 is represented with ……………..
   
   1. A (b) E (c) F  (d) B
      
5. The Decimal Number is in Base ……………….
   
   1. 2 (b) 8 (c) 10  (d) 4
      

       

SECTION B

1. List the different ways of representing data
2. Explain Decimal Number System

WEEK NINE

TOPIC: CONVERSION OF NUMBER BASES

The decimal numbers is repeatedly divided by 2. The remainder after each division is used to indicate the coefficient of the binary number to be formed. It should be therefore noted that binary number from buttom to the top.

Example: Convert the following decimal number to binary

1. 15
2. 7

(1)

15₁₀ = 1111₂

(2)

7₁₀ = 111₂

Example: Convert the following Binary number to Decimal

1. 101₂
2. 11011₂
3. 100110₂

1. 101  =  1 x 2² + 0 x 2¹ + 1 x 2⁰

   =  1×4 + 0x2 + 1×1

   =  4 + 0 + 1

   =  5₁₀

2. 11011  =  1×2⁴ + 1×2³ + 0x2² + 1×2¹ + 1×2⁰

   =  16×1 + 1×8 + 0x4 +1×2 + 1×1

   =  16 + 8 + 0 + 2 + 1

   =  27₁₀

3. 100110  =  1×2⁵ + 0x2⁴ + 0x2³ + 1×2² + 1×2¹ + 0x2⁰

   =  1×32 + 0x16 + 0x8 + 1×4 + 1×2 + 0x1

   =  32 + 0 + 0 + 4 + 2 + 1

   =   32 + 7

   =  39₁₀

EVALUATION

1. Convert the following Decimal into Binary
   1. 33  (b) 25  (c) 50  (d) 16 (e) 37
2. Convert the following Binary to Decimal
   1. 11110101  (b) 101  (c) 1010101  (d) 111010  (e) 1100101001

CONVERSION FROM DECIMAL TO OCTAL NUMBERS

The decimal numbers are repeatedly divided by 8 and the remainder after each division is used to indicate the coefficient of the octal number to be formed. Note that the octal number is derived by writing from button to the top.

Example: Convert the following Decimal to Octal Number

1. 385₁₀
2. 674₁₀

(1)

385₁₀ = 601₈

(2)

674₁₀ = 1241₈

Example: Convert the following Octal number two Decimal

1. 217₈
2. 415₈
3. 3167₈
4. 217₈  =  2×8² + 1×8¹ + 7×8⁰

   =  2×64 + 1×8 + 7×1

   =  128 + 8 +7

   =  143₁₀

5. 475₈  =  4×8² + 7×8¹ + 5×8⁰

   =  256 + 56 + 5

   =  317₁₀

6. 3167₈  =  3×8³ + 1×8² + 6×8¹ + 7×8⁰

   =  1536 + 64 + 48 + 7

   =  1536 + 115

   =  1655₁₀

EVALUATION

1. Convert the following Decimal into Octal

   (a) 679  (b) 988  (c) 544 (d) 238 (e) 864

2. Convert the following Octal to Decimal
   1. 3768  (b) 356  (c) 1550  (d) 600 (e) 11280

CONVERSION FROM DECIMAL TO HEXADECIMAL NUMBERS

The Decimal number is repeatedly divided by 16 and the remainder after each division is used to indicate the coefficient of the hexadecimal number to be formed.

Note that the hexadecimal number is derived by writing from bottom to the top. It should also be noted that numbers from 10 to 16 should be indicated with alphabets from A to F.

Example: Convert the following Decimal numbers to Hexadecimal numbers

1. 469
2. 783
3. 16172

(1)

469₁₀ = 289₁₆

(2)

783₁₀ = 30F₁₆

(3)

16172₁₀ = 3F2C₁₆

Example: Convert the following Hexadecimal to Base 10

1. 305
2. 2EC
3. 11F
4. 305 =  3×16² + 0x16¹ + 5×16⁶

   =  768 + 0 + 5

   =  773₁₀

5. 2EC  =  2×16² + 14×16¹ + 12×16⁰

   =  512 + 252 + 12

   =  512 + 264

   =  778₁₀

6. 11F =  1×16² + 1×16¹ + 15×16⁰

   =  256 + 16 + 15

   =  287₁₀

GENERAL EVALUATION/QUESTIONS

1. Convert the following Decimal into Hexadecimal
   1. 978  (b) 8870  (c) 6470  (d) 832 (e) 46885
2. Convert the following Hexadecimal to Decimal
   1. 2AC  (b) 50FE  (c) 12FF  (d) 510D  (e) 5EC2

3. Convert the following octal numbers to decimal numbers

(a) 352 (b) 462

READING ASSIGNMENT

Computer studies for Junior Secondary Schools 2, p23- p36.

WEEKEND ASSIGNMENT

Instruction: Choose the correct option from the ones lettered A to D

1. Convert the following Decimal number into Binary
   1. 55  (b) 36  (c) 49  (d) 17 (e) 40
2. Convert the following Binary number to Decimal
   1. 10101010  (b) 111111  (c) 10001111  (d) 10111  (e) 10101110
3. Convert the following Octal number to Decimal
   1. 346  (b) 566 (c) 8468  (d) 9000  (e) 3456
4. Convert the following Decimal number into Hexadecimal
   1. 10345  (b) 2045  (c) 7860  (d) 4056  (e) 3987
5. Convert the following Hexadecimal number to Decimal
   1. 2DEF  (b) 5AC  (c) 2390  (d) AD56  (e)23B

SECTION B

1. Convert the following Decimal into Hexadecimal

(a) 978  (b) 8870   (c) 647  (d) 832  (e) 46885

1. Convert the following Hexadecimal to Decimal

(a) 2AC  (b) 50FE   (c) 12FF (d) 510D (e) 5EC2

WEEK TEN

TOPIC: UNIT OF STORAGE IN COMPUTER

Computers work in term of 0s and 1s known as binary digit (i.e. Base 2). It is also called bits (short form of binary digits). This is the only language that the computer understands. Any data or information supplied to the Computer such as letters, figures and symbols must be converted to the language before computer can process such data or information. This is the smallest unit of information that can be stored in a computer and is called bit.

In electronics devices, binary number can represent two voltage levels on and off. For this reason, the binary number system is the core of digital computing.

BIT: A bit which is also called binary digit is the smallest unit of information in a digital computer. It has a value of 1 or 0 which represents true/false in logic and on/off in electronics devices.

BYTE: A byte is a unit of storage in a computer which consists of 8-bits. e.g. 01011101, 11101101 and this is equal to 2 bytes.

NIBBLE: A nibble is a storage unit in a computer and equivalent to 4 bits or half of a byte. .e.g. 0101, 1110 and this is equal to 1 byte.

WORD: A word is a group of fixed numbers of bits in a given computer. It is also described as a group of two bytes.

DOUBLE WORD: A double word consists of 2 words which are equivalent to 4 bytes.

QUARD WORD: It consists of 4 words i.e 8 bytes.

KILOBYTE (KB): This is equivalent to 1024 bytes.

MEGABYTE (MB): This is equivalent to 1024 x 1024 bytes.

GIGABYTE (GB): This is equivalent to 1024 x 1024 x 1024 bytes.

TERABYTE (TB): This is equivalent to 1024 x 1024 x 1024 x 1024 bytes.

CONVERSION OF BYTES TO BITS

1 bytes = 8 bits

2 bytes = 16 bits

3 bytes = 24 bits

5 bytes = 40 bits

Example 1

Convert 4KB to Byte

Solution: 1 KB = 1024 bytes

Therefore, 4 KB = 4 x 1024 = 4096 bytes

Example 2

Convert 2048 bytes to kilobytes

Solution: 1024 bytes = 1KB

Therefore, 2048 bytes = 2048/1024 = 2 kilobyte.

GENERAL EVALUATION/REVISIONAL QUESTIONS

1. Define the following:
   1. BIT (b) BYTE  (c) NIBBLE  (d) WORD  (e) KILOBYTE

2.  Convert (i) 3 bytes to bits (ii) 5 nibbles to bit (iii) 2 words to byte

3. Convert the following: (i) megabyte to kilobyte (ii) kilobyte to byte (iii) 6 bytes to nibble.

READING ASSIGNMENT

A hand book on computer studies for Schools and Colleges, p60- p61.

WEEKEND ASSIGNMENT

Instruction: Choose the correct option from the ones lettered A to D

1.  A computer works in ………….. number system

 (a) Decimal  (b) Octal  (c) Hexadecimal  (d) Binary

2.  ………………. is the smallest unit of information in a digital computer

 (a) Byte (b) Nibble  (c) Word  (d) Bit

3.  A byte consists of ………….. bits (a) 4 (b) 2  (c) 6  (d) 8

4.  A word is equivalent to ………… byte (a) 3  (b) 6  (c) 3  (d) 2

5.  Two kilobytes is equivalent to ………. Bytes (a) 1024 (b) 4096  (c) 3096

 (d) 2048

SECTION B

1.  Explain the following terms (a) Nibble  (b) Word  (c) Byte (d) Megabyte

2.  Convert the followings: (i) 3 bytes to bits (ii) 2 kilobytes to bytes