Explain solid-state flash storage
Describe NAND/NOR flash memory and identify SSDs, SD cards and USB drives as examples.
This sequence follows Cambridge IGCSE Computer Science 0478, 2026–2028 syllabus Version 6. It covers subject content sections 3.1–3.3 only. The separately published 2029–2031 syllabus is not mapped here. Practice is original, self-checked and does not award an official Cambridge grade. Full timed papers and human subject-teacher review remain outstanding.
Before you begin
- No programming language is required. Be comfortable with place value and multiplication; each lesson introduces the computer-science notation it uses.
Work on paper. Try each question before revealing help, and explain why your method works.
Quick readiness check
Which storage type has no moving platter?
What you will learn
- Describe flash storage using transistors and charge
- Identify NAND or NOR technology
- Classify SSDs, SD cards and USB drives
Flash memory stores data in transistor cells
Solid-state flash memory uses NAND or NOR technology. Transistors act as control gates and floating gates; stored electrical charge represents data and can be retained without continuous power.
Apply and check the rule
SSDs, SD cards and USB flash drives use solid-state storage. They have no spinning platter or optical laser, which can make them compact and resistant to mechanical movement, though capacity, cost and write endurance vary by device.
Pause and explain
What is a floating gate used for in flash memory?
Worked example
Which storage method is used in an SD card?
Show the worked solution
- It is solid-state flash memory.
- Its cells use transistor-based NAND or NOR technology.
- No rotating magnetic platter is needed.
Answer Solid-state flash storage
Try a topic test
Choose Easy, Normal or Difficult. Save your answers and open worked review after finishing.
Test this topic →From guided practice to a new situation
Write your answer and reasoning first. Use a hint only if you are stuck. The model solution is for self-checking; your written work is not automatically marked.
Classify an external USB flash drive by storage technology.
Give me a hint
The connection type does not determine the storage mechanism.
Compare my reasoning
- A USB flash drive uses solid-state flash memory.
- Its storage is typically based on NAND or NOR technology.
Solid-state flash storage
Look for these in your work
- Storage technology named
- Flash technology identified
Name two advantages a solid-state drive can have over a mechanical HDD.
Give me a hint
Consider moving parts and access behaviour, while avoiding absolutes.
Compare my reasoning
- An SSD has no spinning platter or moving read head.
- It can be compact and respond quickly, depending on the models compared.
It has no moving mechanical parts and can provide compact, fast access; the exact advantage depends on the devices.
Look for these in your work
- No moving parts
- Practical benefit qualified
A student says an SD card stores data magnetically because the file is made of bits. Explain the distinction.
Give me a hint
Binary is a representation; the storage device has a physical method.
Compare my reasoning
- Bits describe how information is represented.
- An SD card stores data using solid-state flash cells and transistor-based NAND/NOR technology.
- An HDD instead uses magnetic patterns on platters.
Binary describes the data representation, not the medium. An SD card uses solid-state flash cells; an HDD uses magnetic platters.
Look for these in your work
- Representation distinguished
- Flash mechanism stated
- HDD comparison
Common mistakes
- Calling flash storage magnetic because data is represented in binary
- Assuming all flash devices have identical durability or speed
What can you explain now?
Which item is a solid-state flash storage device?
Compare with the explanation
SD card
SD cards use solid-state flash memory, as do SSDs and USB drives.
After trying it yourself, choose your next review. This is your self-assessment.
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Make it stick
Name three solid-state storage examples in this syllabus.
If you needed the solution, close it and solve the problem again from a blank page. A correct answer is stronger when you can explain the reason for each step.