Computer ScienceExam code: 0984
Memory and Storage
Hardware
An exam question can give a scenario and ask which storage type fits best. The five questions to ask:
| Question | Magnetic (HDD) | Solid-state (SSD) | Optical (CD/DVD/Blu-ray) |
|---|---|---|---|
| Need large capacity at low cost? | ✓ Best | Costly per GB | Limited capacity |
| Need fast read/write? | OK | ✓ Best | Slow |
| Need physical durability? | Worst (moving parts) | ✓ Best | Discs scratch easily |
| Need to be portable? | Heavy | ✓ Best | Light but fragile |
| Need very low cost per copy for distribution? | No | No | ✓ Best |
Storage choice by scenario
| Scenario | Best storage |
|---|---|
| The internal main drive of a modern laptop | SSD (fast, durable, silent, low-power) |
| A 12 TB backup drive for a server room | HDD (cheapest per TB, capacity matters more than speed) |
| A music album for sale in a record shop | CD (low cost per disc, well-supported format) |
| A 4K film for retail | Blu-ray (high capacity, established format) |
| A removable storage stick for moving files between computers | USB flash drive (solid-state) |
| The internal storage of a phone | SSD-type flash (no moving parts, small, durable) |
| A games console with a huge installed library | A combination: fast SSD for currently-played games, large HDD for older titles |
Exam tip
Pair each feature with its benefit for the device
When a question asks for the most suitable secondary storage for a smartphone and an explanation (set once in the 17 papers), the name (solid-state) is one mark and the explanation three, from a list in which a feature and its consequence are separate points. So "no moving parts" is one point and "so the data survives the phone being dropped" a second; "fast read and write speeds" one and "so files load quickly" another. Other credited pairs: small and thin, so it fits the phone; lightweight; needs little power, so the battery lasts; runs cool and quiet.