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Secondary Storage

FoundationHigherAQA

Master Secondary Storage for GCSE Computer Science with this free worksheet and full mark scheme — Foundation and Higher exam-style questions with worked answers. Secondary storage is non-volatile and includes solid state and magnetic devices.

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These worksheets and mark schemes are original, written for Virtus Academy and checked against the current AQA specification. Every worksheet comes with a full mark scheme.

Foundation

WorksheetFoundation · PDFMark SchemeFoundation · PDF

Higher

WorksheetHigher · PDFMark SchemeHigher · PDF

Topic overview

Secondary storage holds data permanently, retaining it when the computer is switched off. Three types must be compared.

Magnetic storage uses a spinning disk with a moving read-write head. It offers large capacity at low cost per gigabyte, but the moving parts make it slower and vulnerable to damage if dropped.

Solid state storage has no moving parts, using flash memory instead. It is faster, more durable, silent and uses less power, but costs more per gigabyte and has a limited number of write cycles. Optical storage uses a laser to read pits burned into a disc. It is cheap and portable but has small capacity and is easily scratched. Choosing between them means weighing capacity, speed, durability, portability and cost.

Revision notes

Magnetic storage

A spinning disk with a moving read-write head.

Advantages: large capacity, low cost per gigabyte. Disadvantages: moving parts make it slower, noisier and easily damaged if dropped while running.

Solid state storage

Flash memory with no moving parts.

Advantages: faster, more durable, silent, lower power consumption. Disadvantages: higher cost per gigabyte, and a limited number of times each cell can be written to.

Optical storage

A laser reads pits burned into the surface of a disc.

Advantages: very cheap, portable, useful for distributing software. Disadvantages: small capacity compared with the alternatives, slow, and easily scratched.

Key points

  • Secondary storage is non-volatile.
  • Magnetic storage uses a spinning disk.
  • Magnetic offers large capacity cheaply.
  • Solid state has no moving parts.
  • Solid state is faster and more durable.
  • Optical storage uses a laser to read discs.

Worked examples

Example 1

State two advantages of solid state storage over magnetic storage. [2 marks]

Working

It is faster, because there are no moving parts to wait forgive the first advantage
It is more durable and less likely to be damaged if the device is droppedgive the second advantage

Example 2

Explain why magnetic storage is often chosen for a server storing very large amounts of data. [2 marks]

Working

Magnetic storage has a much lower cost per gigabyte than solid statestate the advantage
so a large capacity can be provided far more cheaply, and speed matters less for archived dataexplain the reasoning

Example 3

Give one disadvantage of optical storage. [1 mark]

Working

It has a small capacity compared with magnetic and solid state storage, and is easily scratchedgive a disadvantage

Common mistakes

  • Saying solid state has no disadvantages.

    Cost per gigabyte and limited write cycles are both real.

  • Confusing optical with magnetic.

    Optical uses a laser and a disc; magnetic uses a spinning platter and a head.

  • Recommending a type without justifying it.

    Weigh capacity, speed, durability, portability and cost.

  • Saying secondary storage is volatile.

    It is non-volatile — that is its purpose.

Exam tips

  • Weigh several factors when recommending a storage type.
  • Give both advantages and disadvantages.
  • Link the choice to the specific situation described.
  • Remember cost per gigabyte, not just total cost.

Key terms

Secondary storage
Non-volatile storage retaining data without power.
Magnetic storage
Storage using a spinning disk and read-write head.
Solid state storage
Flash storage with no moving parts.
Optical storage
Storage read by a laser, such as a DVD.

Related topics

Written and reviewed against the current AQA specification. Spotted an error? Let us know.