# UNITS OF STORAGE IN THE COMPUTER

Subject:

Christian Religious Knowledge

Term:

First Term

Week:

Week 5

Class:

JSS 2 / BASIC 8

Previous lesson: Pupils have previous knowledge of

### TYPES OF OPERATING SYSTEM

that was taught in their previous lesson

Topic:

UNITS OF STORAGE IN THE COMPUTER

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

• define units of computer storage
• calculate the units of computer storage

Instructional Materials:

• Wall charts
• Pictures
• Related Online Video
• Flash Cards

Methods of Teaching:

• Class Discussion
• Group Discussion
• Explanation
• Role Modelling
• Role Delegation

Reference Materials:

• Scheme of Work
• Online Information
• Textbooks
• Workbooks
• 9 Year Basic Education Curriculum
• Workbooks

Content

UNITS OF STORAGE IN THE COMPUTER

Introduction to Units of Storage in the Computer

Computer memory is a storage location where data/information are kept or stored. All data, information, text, numbers, audio, video etc are converted into 0’s and 1’s and stored in different types of storage in order to be processed by the computer CPU. Hence, we have various units of storage. These are;

(i) Binary digit (Bit)

(ii) Nibble

(iii) Byte

(iv) Word

Binary Digit (Bit)

It is the first and the smallest unit of computer memory. It is a unit of data that can be either of the two conditions – 0 or 1. Groups of bits make up storage units in the computer, called bytes (characters), words which are manipulated as a group. Each of the 0 and 1 in the diagram below indicates a bit.

Nibble

It is a storage unit that is in a sequence of 4 bits. It is equivalent to 4 bits (half of a byte) i.e 0101, 1110, 0101, 1101, 1001 etc. E.g.

Binary Table (BYTE)

A group of 8 bits is called a byte. A byte is the basic and the most common unit in the computer’s memory. One byte is one character. A character can be a number, letter or symbol. Each byte resides temporarily on the computer’s memory and this specific location is called an address. i.e. 01011101, 11110110 01010110 etc.

Other higher memory units associated with bytes are:

(i) Kilobyte

(ii) Megabyte

(iii) Gigabyte

(iv) Terabyte

KILOBYTE (KB): This is equivalent to 210 = 1,024 bytes

MEGABYTE (MB): A megabyte is equivalent to 220 = 1,048,576 bytes

GIGABYTE (GB): A gigabyte is equivalent to 230 = 1,073,741824 bytes

TERABYTE (TB): A terabyte is equivalent to 240 = 1,099,511,627,780 bytes

EVALUATION

1. How many bits are in a byte?
2. What is a kilobyte?
3. List three units of storage in the computer

Word Length

A word is a group of fixed numbers of bytes which always varies from computer to computer but is fixed for each computer. The length of a computer word is called a word length, which is in the range of 1 byte to 64 bytes. It implies the number of bits which can be handled in a single operation.

Other higher memory units associated with WORD are:

(i) Double word – is made up of 2 words which is equal to 4 bytes (32 bits)

(ii) Quad word – is made up of 4 words i.e. 2 double words, which equals to 8 bytes (64 bits)

WORKING EXAMPLES

1 byte = 8 bits

1 kilobyte (KB) = 210 = 1,024 bytes

1 megabyte (MB) = 210 × 210 =220 = 1,048,576 bytes

I gigabyte (GB) = 210 × 210 × 210 = 230 = 1,073,741,824 bytes

I terabyte (TB) = 210 × 210 × 210 × 210 = 240 = 1,099,511,627,780 bytes

FURTHER WORKINGS

Bit = 0 or 1

4 bits = 1 nibble

2 nibbles = 8 bits and 8 bits = 1 byte

3 nibbles = (3 × 4) bits = 12 bits

4 nibbles = (4 × 4) bits = 16 bits

5 nibbles = (5 × 4) bits = 20 bits

Conversion of Bytes to Bits

1 bytes = 8 bits

2 bytes = 16 bits

3 bytes = 24 bits

5 bytes = 40 bits

Unlike the metric system where I kilometer (km) is equal to 1000 meter the sub-units of byte are converted as follows.

EXAMPLE 1

Converts 2 kilobytes to byte

Solution

1 KB = 1024bytes

2 KB = 2(1024) bytes = 2048 bytes.

EXAMPLE 2

Convert 4KB to Byte

Note IKB = 1024 bytes

4KB = 4(1024) bytes

= 4096 bytes

EXAMPLE 3

Convert 2048 bytes to kilobytes

Recall,

1024 bytes = 1KB

2048 bytes = 2048bytes × 1KB / 1024 bytes

= 2 kilobytes

EXAMPLE 4

Change 3 megabytes to byte

1MB = 1,048, 576 bytes

3 MB = 3(1048, 576 bytes)

= 3,145,728 bytes

Conversion of Words to Bytes

Recall 1 word = group of 2 bytes

(a) 1 word = 2 bytes

2 bytes = 16 bits

(b) 2 words = 2(2bytes)

= 2 × 16 bits

= 32 bits

(c) 4 words = 4(2 bytes)

= 4 × 16 bits

= 64 bits

(d) Convert 3,145,728 bytes to MB

Solution: To change 3,145,728 to MB

1, 048,576B = 1MB

3, 145,728   = 3,145,728 x 1MB / 1,048,576

= 3MB

1. How do you convert bytes to kilobytes?
2. What is the difference between bytes and kilobytes?
3. Why is it important to know how to convert bytes to kilobytes?
4. When would you use this conversion?
5. How do you remember which way the conversion goes?

Presentation

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

Conclusion

The class teacher wraps up or concludes the lesson by giving out a 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 by the pupils.

He or she makes the necessary corrections when and where the needs arise.

### Evaluation

EVALUATION

Explain the following terms

(a) Nibble (b) Word (c) Double words (d) Quad word (e) Byte (f) Kilobyte (g) Megabyte (h) Gigabyte

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

1. What is a kilobyte?
2. What is a megabyte?
3. What is a gigabyte?
4. What is a terabyte?
5. How much data can be stored in each one of those measurements?