Sparklabs Learning / Digital Technology
JSS 1 First Term
Week 7: Storage Devices
- School
- Creative Brains Academy
- Subject
- Digital Technology
- Pack
- Learner notes
- Prepared
- 7 November 2026
Week index
- 01Introduction to ICT and Information Ages
- 02History, Evolution and Generations of Computers
- 03What Is a Computer and Its Parts
- 04Functions of Parts, Hardware and Software
- 05Input and Output Devices
- 06Basic Typing Skills
- 07Storage Devices
- 08Simple Uses of the Internet
- 09Introduction to MS Word
- 10Creating and Saving Documents
- 11Revision and Examination Preparation
- 12Examination
Week 7 / First Term
Storage Devices
Monday 19 October 2026 to Friday 23 October 2026
Lesson notes
Learning Objectives
- Define storage and state why a computer needs storage.
- Differentiate between primary and secondary storage.
- Name the common secondary storage devices.
- State the units used to measure storage.
What Storage Does
Storage keeps data so that it can be used again later. A computer needs storage for three reasons. Programs must be available when the machine starts. Data must survive after the machine is switched off. Work must be kept while other work is being done.
The amount of storage is measured in bits and bytes. A bit is the smallest unit and holds a single 0 or 1. A byte is made of eight bits and holds one character. Larger units are the kilobyte, megabyte, gigabyte and terabyte.
Primary Storage
Primary storage is the working memory of the computer. It is very fast and is used directly by the processor. RAM is the main part. RAM holds programs and data only while the computer is on, and its contents are lost when the power goes off.
ROM is read only memory. Its contents are fixed when it is made and it cannot be written to by the user. ROM keeps the start up instructions that the computer needs before any operating system loads. Cache is a small fast memory that holds data the processor is about to use.
Secondary Storage
Secondary storage keeps data permanently. It is slower than primary storage but much larger. The hard disk drive stores the operating system, programs and files. A solid state drive does the same job faster because it has no moving parts.
Removable secondary storage includes the flash drive, memory card, optical disc and external hard disk. Optical discs come as CD, DVD and Blu-ray. The flash drive and memory card are now more common because they are small, fast and cheap.
Comparing Storage Devices
Storage devices are compared by capacity, speed, portability and cost. A hard disk has large capacity but is fixed inside the computer. A flash drive has smaller capacity but can be carried. An optical disc can be read easily but has low capacity and can be scratched.
Learners should check free space before saving large files. Deleting a file frees space, but the space is only returned to the system when the Recycle Bin is emptied.
How Data Is Stored and Measured
A computer stores everything in binary, using only the digits 0 and 1. Each 0 or 1 is called a bit, and eight bits make a byte, which can hold one character such as the letter A.
Storage capacity is measured in units that grow larger. A kilobyte is about one thousand bytes, a megabyte is about one million bytes, a gigabyte is about one thousand megabytes, and a terabyte is about one thousand gigabytes.
Types of Secondary Storage
Different storage devices suit different jobs. A hard disk drive uses spinning magnetic discs and gives a large capacity at low cost. A solid state drive uses electronic chips, so it is faster, quieter and more durable. A flash drive and a memory card are small and portable. Optical discs such as CDs and DVDs store data that a laser reads.
| Unit | Approximate size |
|---|---|
| Bit | One single 0 or 1 |
| Byte | 8 bits, one character |
| Kilobyte | 1024 bytes |
| Megabyte | 1024 kilobytes |
| Gigabyte | 1024 megabytes |
| Terabyte | 1024 gigabytes |
| Device | Type | Capacity | Portable |
|---|---|---|---|
| RAM | Primary | Small | No |
| ROM | Primary | Small and fixed | No |
| Cache | Primary | Very small | No |
| Hard disk drive | Secondary | Large | No |
| Solid state drive | Secondary | Large | No |
| Flash drive | Secondary | Medium | Yes |
| Memory card | Secondary | Small | Yes |
| CD and DVD | Secondary | Medium | Yes |
| External hard disk | Secondary | Very large | Yes |
| Unit | Size |
|---|---|
| Bit | A single 0 or 1 |
| Byte | Eight bits, about one character |
| Kilobyte | About one thousand bytes |
| Megabyte | About one million bytes |
| Gigabyte | About one thousand megabytes |
| Terabyte | About one thousand gigabytes |
Practical Work
- Check and write down the total and free space of the laboratory computer hard disk.
- Insert a flash drive, create a folder on it and copy three files into the folder.
- Measure the size of three files of different types and record which type uses the most space.
- Empty the Recycle Bin and record how much free space is regained.
- Compare the speed of opening the same file from the hard disk and from a flash drive.
Scenario-Based Questions
- A pupil needs space to save a large video but the computer reports that there is not enough room. Give two ways to create space.
- Explain why a computer will not start properly if the RAM is faulty.
- A school wants to give each learner 8GB of portable storage. Name the device and state two reasons it is suitable.
- Differentiate between RAM and ROM using a table of four points.
- Explain what is lost and what is kept when a computer is switched off.
- A file of 40MB is copied onto a flash drive that has 25MB free. Explain what happens and why.
- Explain why a solid state drive makes a computer feel faster even when the processor is unchanged.