← IGCSE Computer Science Paper 1

Writing exam answers about data storage

A full-mark storage answer uses the correct term (e.g. virtual memory, ROM, SSD) and links each point to a reason with 'because', rather than just naming or listing things.

Part of: IGCSE Computer Science 0478 — 3.3 Data Storage — Module 30

Understanding Writing exam answers about data storage in IGCSE Computer Science Paper 1

What it does: The sentence states an advantage of cloud storage and explains it with 'because', as required for full marks. It uses the key terms laser, pits and lands and gives a reason, so it is a full-mark description. Virtual memory is not hardware. It is an area of secondary storage that the OS uses when RAM is full. ROM is non-volatile and stores the start-up instructions. RAM is volatile and loses its contents when power is lost. Use 'because' to link the point to a reason. Repeating the question wording does not earn a mark. The answer gives a correct term and a reason, which is what examiners reward, not just a bare statement.

Common mistakes: RAM is volatile because it loses its data when the power is off. It should say 'RAM is volatile memory'. Calling it non-volatile mixes up RAM and ROM. ROM is non-volatile, so it keeps its data without power. This is the reason it can store the bootstrap. The line should be 'It keeps data without power'.

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This module's key terms are also in a printable crossword (Modules 325–341) and word search (Modules 325–354).

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Learning
Duo
Which answer to 'Why does a computer need secondary storage?' gets the mark?
Secondary storage is where the computer keeps thingsBecause RAM is volatile, secondary storage keeps data when the power is off
Matches
"Virtual memory is extra RAM added to the computer."
↓
Virtual memory is not extra RAM hardware. It is part of secondary storage used as if it were RAM when RAM is full.
Applying
Meanings
Term
point because reason
Meaning
A full-mark storage answer uses the correct term (e.g. virtual memory, ROM, SSD) and links each point to a reason with 'because', rather than just naming or listing things.
Practice
RAM is volatile because it loses its data when the power is off.
Testing
Gaps
An SSD is faster it has no
Check Answer
Spots
1RAM is non-volatile memory
2Data is lost without power

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Quick Questions

1. Which answer to 'Why does a computer need secondary storage?' gets the mark?
A. Because RAM is volatile, secondary storage keeps data when the power is off ✓
B. Secondary storage is where the computer keeps things
A full-mark answer links the point to a reason. Naming the device is not enough; explain that secondary storage is non-volatile.
2. Which sentence uses the correct term for virtual memory?
A. Virtual memory is extra RAM chips added to the motherboard
B. Virtual memory is part of the secondary storage used as if it were RAM ✓
Virtual memory is not hardware. It is an area of secondary storage that the OS uses when RAM is full.
3. Which answer explains virtual memory in the correct order?
A. RAM fills up, so pages not in use move to virtual memory, and they are moved back when needed ✓
B. Pages move back from virtual memory, then RAM fills up, then pages are moved out
The order matters: RAM becomes full, unused pages are moved out to virtual memory, then they are swapped back in when needed.
4. Which answer correctly describes how an SSD stores data?
A. It uses transistors as floating gates to trap electrons, which represent 1s and 0s ✓
B. It uses a laser to burn pits and lands onto a spinning disc
Solid-state storage uses floating gate transistors with no moving parts. Pits and lands belong to optical storage.
5. Which answer correctly describes magnetic storage?
A. A laser reflects off pits and lands on the platter to store 1s and 0s
B. Electromagnets in the read/write head magnetise areas on the platter to store 1s and 0s ✓
Magnetic storage uses magnetised areas on platters. Lasers reflecting off pits and lands is optical storage.

Match the Pairs

"An SSD is faster because it has no moving parts." → A full-mark sentence: it names the device (SSD) and links the point to a reason using 'because'.
"Virtual memory is used when RAM is full, so pages move to the hard drive." → An answer that explains virtual memory in the correct order: RAM fills, then pages are moved to secondary storage.
Compare cloud and local storage by giving a point and a reason linked with 'because'. → "Cloud storage lets me access files anywhere because they are stored on remote servers via the internet."
Describe how optical storage works using the correct terms, not vague words. → "A laser reads the pits and lands on the disc surface because they reflect light differently."
"Virtual memory is extra RAM added to the computer." → Virtual memory is not extra RAM hardware. It is part of secondary storage used as if it were RAM when RAM is full.
"ROM stores the data and programs currently being used and is wiped when the power is off." → This mixes up RAM and ROM. It describes RAM, which is volatile. ROM is non-volatile and keeps the start-up instructions.

Key Term

point because reason
A full-mark storage answer uses the correct term (e.g. virtual memory, ROM, SSD) and links each point to a reason with 'because', rather than just naming or listing things.

Fill in the Blanks

1. An SSD is faster because it has no moving parts.
Hint: Type the linking word that connects a point to its reason.
2. RAM is volatile because it loses its data when the power is turned off.
Hint: Type the term for memory that loses its contents without power.
3. Virtual memory is an area of secondary storage, not extra RAM hardware.
Hint: Type the type of storage that virtual memory borrows space from.
4. ROM stores the bootstrap program because it is non-volatile and keeps its data.
Hint: Type the name of the start-up program that ROM holds.
5. Cloud storage needs an internet connection, so local storage is better offline.
Hint: Type what a user must have to reach files stored in the cloud.

Spot the Error

Question 1
A RAM is non-volatile memory
B Data is lost without power
C It holds running programs
Line A — RAM is volatile because it loses its data when the power is off. It should say 'RAM is volatile memory'. Calling it non-volatile mixes up RAM and ROM.
Question 2
A ROM is non-volatile
B It loses data without power
C so it can hold the bootstrap
Line B — ROM is non-volatile, so it keeps its data without power. This is the reason it can store the bootstrap. The line should be 'It keeps data without power'.
Question 3
A 1 RAM becomes full
B 2 Idle pages move to ROM
C 3 Needed pages move back
Line B — In virtual memory, idle pages move from RAM to secondary storage (the disk), not to ROM. ROM is read-only and cannot be used for swapping. It should be '2 Idle pages move to disk'.
Question 4
A Cloud suits remote workers
B because files are online
C Local storage works offline
D because data is on the server
Line D — Local storage works offline because the data is on the user's own device. Data on a server describes cloud storage. It should be 'because data is on the device'.
Question 5
A HDD is magnetic storage
B Platters hold tracks, sectors
C The head burns pits in disk
Line C — A magnetic HDD writes data by using an electromagnet in the head to magnetise areas of the platter. Burning pits is how optical discs work. It should be 'The head magnetises the disk'.

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