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IGCSE · Practice questions · Primary storage: RAM and ROM

Volatile or not.

Six original Cambridge-style questions on RAM and ROM, with mark-scheme style solutions.

Original questions All questions on this page are original work, written in the Cambridge IGCSE style. They are not from past papers. They test the same concepts and skills the syllabus rewards.
Keep these straight

Compare in pairs.

01
Recall
[1 marks]

State what is meant by primary storage.

  • Storage that is directly accessed by the CPU. ✓
02
Explain
[3 marks]

Describe the role of RAM in a computer.

  • It stores the programs/instructions and data currently in use (including the operating system). ✓
  • So the CPU can access them directly and quickly. ✓
  • Its contents can be read and written and are lost when the power is turned off (volatile). ✓
03
Explain
[4 marks]

Give two differences between RAM and ROM.

  • RAM is volatile; ROM is non-volatile. ✓
  • RAM can be read and written; ROM can only be read. ✓
  • RAM stores programs and data in use; ROM stores the start-up instructions. ✓
  • (Any two differences, each with both sides, for 2 marks each.) ✓
04
Explain
[3 marks]

Explain why a computer needs both RAM and ROM.

  • ROM is non-volatile, so it keeps the start-up instructions when the power is off, ready for when the computer is turned on. ✓
  • These instructions load the operating system into RAM. ✓
  • RAM is needed to hold programs and data that are in use and must be changed (read and written) quickly. ✓
05
Apply
[3 marks]

State whether RAM or ROM would store each item: (a) the instructions that start a games console; (b) a game level being played; (c) the player's current score.

  • (a) ROM. ✓
  • (b) RAM. ✓
  • (c) RAM. ✓
06
Analysis
[2 marks]

A student says: "ROM is used because it is faster than RAM." Explain why this is not the reason ROM is used.

  • ROM is used because it is non-volatile / its contents are kept without power. ✓
  • And it cannot be changed, so the start-up instructions are not lost or altered (speed is not the reason). ✓

Mark this once you have attempted all six and checked your working. It records a Practiced badge on the topic and adds a one-time bonus. Revealing the solutions alone does not count.