AQA · GCSE · Computer Science
Course version: 8525 · Version from Sept 2020
Be aware of different types of secondary storage (solid state, optical and…
Full specification wording
Systems architecture: Be aware of different types of secondary storage (solid state, optical and magnetic).
Secondary storage comes in three main types.
Checked against the AQA 8525 specification (opens in a new tab) on .
- Point 26 of 30
Study notes
From the checked teaching notes for this specification point.
The idea
Secondary storage comes in three main types. Solid state storage, such as SSDs, USB flash drives and memory cards, stores data in flash memory with no moving parts; it is fast, durable and silent but costs more per gigabyte. Magnetic storage, such as hard disk drives and magnetic tape, stores data using magnetised areas on a spinning platter or tape; it offers large capacity at low cost per gigabyte but has moving parts and is slower. Optical storage, such as CDs, DVDs and Blu-ray discs, stores data as pits and lands read by a laser; it is cheap and portable but has lower capacity and can be scratched. Learners should recognise each type, give an example device and state a typical use, such as an SSD in a laptop, a hard disk in a server, or a DVD for distributing a film.
What earns the marks
- Solid state storage uses flash memory with no moving parts; examples include SSDs, USB flash drives and memory cards.
- Magnetic storage uses magnetised areas on a spinning platter or tape; examples include hard disk drives and magnetic tape.
- Optical storage uses a laser to read pits and lands on a disc; examples include CDs, DVDs and Blu-ray discs.
- Each type has trade-offs: solid state is fast and durable but costly per gigabyte; magnetic offers large cheap capacity; optical is cheap and portable but lower capacity.
Common mistakes and how to put them right
Classifying a USB flash drive as magnetic storage.
Put it right: It is solid state, using flash memory.
Describing a hard disk drive as optical because it uses a laser.
Put it right: Hard disks are magnetic; optical drives use a laser.
Assuming optical discs have the highest capacity.
Put it right: Magnetic and solid state drives generally hold far more data.
Exam tips
- For each type, name a specific example device and one typical use to secure the mark.
- State the underlying technology: flash memory for solid state, magnetised areas for magnetic, laser-read pits and lands for optical.
- Give one advantage and one drawback per type rather than listing only names.
Try the lesson
The start of the Systems architecture: Be aware of different types of secondary storage (solid state, optical and magnetic). lesson, made from checked teaching notes for this specification point.
Have a go first
Which of these is an example of magnetic secondary storage?
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