Hard Disk Drive (HDD) — stores data on spinning magnetic platters using a read/write head.
CD / DVD / Blu-ray — laser reads/writes data as pits and lands on a spinning disc.
SSD / USB Flash — stores data in flash memory chips. No moving parts.
Directly accessible by the CPU. Very fast. Small capacity.
Not directly accessible by CPU. Slower but large and persistent.
Loses data when power is switched off.
Example: RAM — if your computer crashes before saving, work is lost.
Retains data when power is removed.
Examples: ROM, HDD, SSD, USB flash, optical discs.
1. State two differences between a solid state drive (SSD) and a hard disk drive (HDD). [2 marks]
Mark scheme — any 2 (1 mark each, must be stated as a comparison):
2. Explain why RAM is described as volatile storage. [2 marks]
Mark scheme:
3. A school is choosing between optical discs (DVDs) and USB flash drives to distribute software to students. Give two reasons why USB flash drives would be a better choice. [4 marks]
Mark scheme — 2 marks per reason (point + explanation):
4. Explain the difference between primary storage and secondary storage, giving one example of each. [4 marks]
Mark scheme: