Basic Computer Hardware Components II

Basic Computer Hardware Components II: Storage Units

Subject: Digital Technologies | Class: JSS 1 | Term: First Term | Week: 6

TOPIC: Basic Computer Hardware Components II: Storage Units
CLASS: JSS 1 (Basic 7)
TERM: First Term
WEEK: 6
DURATION: 80 Minutes

1. Introduction

Every time we use a computer, smartphone or tablet, we work with digital information. This information may include documents, photographs, music, videos, applications and other files.

For this information to be kept and used again later, it must be stored. Computers therefore contain different types of storage components and devices that help to keep digital information.

In this lesson, we will learn about primary storage, secondary storage, RAM, ROM, hard disks, flash drives and storage measurements.

2. Meaning of Computer Storage

Computer storage is the process or means by which digital data and information are kept so that they can be used immediately or retrieved later.

For example, when you save a document on a computer, take a photograph with a smartphone or copy a video to a flash drive, the information is being stored.

Examples of information that can be stored

• Text documents
• Photographs
• Music
• Videos
• Computer programs
• School assignments
• Presentations
• Digital records

3. Types of Computer Storage

Computer storage can broadly be divided into two major categories:

1. Primary Storage
2. Secondary Storage

4. Primary Storage

Primary storage is the storage area that the computer uses directly while processing data and running programs.

Primary storage is closely connected with the computer's processor. It provides information that the processor needs to perform its operations.

Two important examples of primary memory are RAM and ROM.

RAM – Random Access Memory

RAM stands for Random Access Memory. It temporarily holds data and instructions that the computer is currently using.

When you open a program, type a document or work on a file, some of the information being used is held in RAM.

RAM is generally described as volatile memory because its contents are lost when the computer is switched off or loses power.

ROM – Read-Only Memory

ROM stands for Read-Only Memory. It stores instructions or information that is retained when the computer is switched off.

ROM helps provide important instructions needed for starting and operating a computer system. Unlike ordinary RAM, its contents are not normally lost simply because the power is turned off.

RAM and ROM Compared

RAM	ROM
Random Access Memory	Read-Only Memory
Used for data and programs currently in use.	Stores important instructions that are retained.
Generally volatile.	Non-volatile in normal use.
Its contents are lost when power is removed.	Its stored information is retained when power is removed.

5. Secondary Storage

Secondary storage refers to storage devices used to keep data and information for longer-term use.

Secondary storage normally provides much more storage capacity than primary memory and is used for keeping files even after the computer has been switched off.

Examples of Secondary Storage Devices

• Hard disk drive (HDD)
• Solid-state drive (SSD)
• USB flash drive
• Memory card
• External hard drive
• Optical discs such as CDs and DVDs

6. Hard Disk

A hard disk drive (HDD) is a storage device used to store large amounts of digital information.

It can store operating systems, applications, documents, photographs, videos and other files.

Modern computers may also use solid-state drives (SSDs). SSDs store data electronically and have no moving disk platters.

7. Flash Drive

A flash drive is a small portable storage device that uses flash memory to store digital information.

Flash drives are commonly connected to computers through a USB port. They are useful for transferring and carrying files from one computer to another.

Uses of Flash Drives

• Storing school assignments
• Transferring documents
• Carrying photographs and videos
• Backing up important files
• Moving files between compatible devices

8. Memory Card

A memory card is a small removable storage device commonly used in smartphones, digital cameras and other electronic devices.

Examples include SD cards and microSD cards.

9. Storage Measurements

Digital information is measured using different units. Some of the common units include:

Unit	Meaning	Use
Bit	Binary digit	The smallest basic unit of digital information.
Byte	Group of 8 bits	A common basic unit for representing digital data.
KB	Kilobyte	Used for relatively small amounts of digital information.
MB	Megabyte	Used for files such as images, documents and some applications.
GB	Gigabyte	Commonly used to describe the capacity of phones, computers and storage devices.
TB	Terabyte	Used for very large storage capacities.

Remember: In everyday computing, storage capacities are commonly expressed using units such as MB, GB and TB. The exact numerical relationship between units can depend on whether decimal or binary conventions are being used.

10. Examples of Storage Capacity

Device / File	Possible Storage Description
Small document	May be measured in KB
Photograph	May be measured in MB
Video file	May be measured in MB or GB
USB flash drive	Often measured in GB
Computer hard drive	Often measured in GB or TB

11. Importance of Data Storage

Data storage is important because it allows users and organizations to keep information for present and future use.

Major importance of storage includes:

1. Keeping information: Storage allows users to save documents, pictures, videos and other files.
2. Future use: Stored information can be retrieved when it is needed later.
3. Data backup: Storage devices can be used to keep additional copies of important files.
4. File transfer: Portable storage devices can help users move files between compatible devices.
5. Running software: Applications and operating-system files need storage space.
6. Record keeping: Schools, businesses and organizations can store important records digitally.

12. Primary and Secondary Storage at a Glance

Primary Storage	Secondary Storage
Used directly by the computer during processing.	Used mainly for long-term storage.
Examples include RAM and ROM.	Examples include HDDs, SSDs, flash drives and memory cards.
Usually has less capacity than secondary storage.	Usually provides larger storage capacity.
Located within or closely connected to the main computer system.	Can be internal or removable/external.

13. Good Storage Practices

Students should observe the following practices when handling storage devices:

• Keep storage devices away from water and excessive heat.
• Handle removable storage devices carefully.
• Safely eject removable drives when required.
• Keep important files backed up.
• Avoid deleting important files accidentally.
• Protect computers and storage devices from malware.
• Keep storage devices in safe places when not in use.

14. Class Activity

Activity 1: Identify the following devices:

1. RAM
2. Hard disk/SSD
3. USB flash drive
4. Memory card
5. ROM

Activity 2: Classify the following as primary or secondary storage:

RAM, ROM, flash drive, hard disk, SSD and memory card.

Activity 3: Arrange these storage units from smaller to larger:

GB, bit, TB, byte and MB.

15. Summary

• Computer storage is used to keep digital data and information.
• Computer storage can be divided into primary and secondary storage.
• RAM temporarily holds data and instructions currently being used.
• ROM stores important instructions that are retained when power is removed.
• Hard disks and SSDs are common storage devices.
• Flash drives are small and portable storage devices.
• Memory cards are commonly used in smartphones, cameras and other devices.
• Digital storage is measured using units such as bit, byte, MB, GB and TB.
• Data storage is important for saving, retrieving, backing up and transferring information.

16. Evaluation Questions

1. What is computer storage?
2. State the two major types of computer storage.
3. What does RAM stand for?
4. What does ROM stand for?
5. State one difference between RAM and ROM.
6. Mention four examples of secondary storage devices.
7. What is a flash drive?
8. What is a memory card?
9. What is a bit?
10. State three reasons why data storage is important.

17. Assignment

1. Define primary storage and secondary storage.
2. Write three differences between RAM and ROM.
3. List five secondary storage devices.
4. Explain the meaning of bit, byte, MB, GB and TB.
5. State five importance of data storage.

18. Interactive Practice Quiz

Choose the correct answer for each question.

1. Which of the following is an example of primary memory?

A. RAM B. Flash drive C. Memory card D. DVD

2. What does RAM stand for?

A. Read Access Memory B. Random Access Memory C. Rapid Application Memory D. Random Application Module

3. Which device is commonly used as portable secondary storage?

A. Monitor B. Keyboard C. USB flash drive D. Mouse

4. Which of these is the smallest basic unit of digital information?

A. Gigabyte B. Byte C. Bit D. Terabyte

5. Which storage unit is commonly used for very large storage capacities?

A. Bit B. Byte C. Terabyte D. Kilobyte