Pearson Edexcel · GCSE · Computer Science
Course version: 1CP2 · Version from Sept 2020
Understand the role of secondary storage and the ways in which data is…
Full specification wording
Hardware: 3.1.2 understand the role of secondary storage and the ways in which data is stored on devices (magnetic, optical, solid state)
Secondary storage provides non-volatile, long-term storage for data and programs when the computer is switched off.
Checked against the Pearson Edexcel 1CP2 specification (opens in a new tab) on .
- Point 2 of 3
- 4 key terms
Study notes
From the checked teaching notes for this specification point.
The idea
Secondary storage provides non-volatile, long-term storage for data and programs when the computer is switched off. It is not directly accessed by the CPU as main memory is; data must first be loaded into RAM. Magnetic storage, such as a hard disk drive, stores data by magnetising tiny areas on a spinning platter, with read/write heads detecting or changing the magnetic state. Optical storage, such as a CD, DVD or Blu-ray disc, stores data as pits and lands on a reflective surface; a laser beam is reflected differently by pits and lands, and the pattern is interpreted as binary. Solid state storage, such as a USB flash drive or solid-state drive, stores data in flash memory chips using electrical charge in floating-gate transistors; there are no moving parts. Each method has different characteristics of speed, capacity, durability and cost, but all provide non-volatile storage.
What earns the marks
- Secondary storage is non-volatile and used for long-term storage of data and programs.
- Secondary storage is not directly accessible by the CPU; data must be transferred into main memory (RAM) before it can be processed.
- Magnetic storage stores data by magnetising areas of a magnetic medium, for example a spinning platter in a hard disk drive, and read/write heads detect or change the magnetic state.
- Optical storage stores data as pits and lands on a reflective surface; a laser reads the pattern of reflections as binary.
- Solid state storage stores data using electrical charge in flash memory chips, with no moving parts.
- Examples: magnetic – hard disk drive; optical – CD, DVD, Blu-ray; solid state – USB flash drive, solid-state drive.
Common mistakes and how to put them right
Thinking secondary storage is directly accessed by the CPU.
Put it right by stating that data must first be copied into RAM before the CPU can use it.
Confusing magnetic and optical storage.
Put it right: Magnetic uses magnetised areas and read/write heads, while optical uses pits and lands read by a laser.
Believing solid state storage uses moving parts.
Put it right: Solid state storage has no moving parts and stores data as electrical charge in flash memory chips.
Saying secondary storage is volatile.
Put it right: Secondary storage is non-volatile and retains data when power is removed.
Exam tips
- For multiple-choice questions, match the storage technology to its method: magnetic – magnetised areas; optical – pits and lands read by laser; solid state – electrical charge in flash memory.
- Remember that secondary storage is non-volatile and is used for long-term storage, while RAM is volatile main memory.
- If an option describes moving parts, check whether it applies to magnetic or optical storage; solid state has none.
Try the lesson
The start of the Hardware: 3.1.2 understand the role of secondary storage and the ways in which data is stored on devices (magnetic, optical, solid state) lesson, made from checked teaching notes for this specification point.
Have a go first
A student inserts a DVD into a laptop drive. Which type of secondary storage reads the data by shining a laser onto the disc surface and measuring the light reflected back?
Listen
Secondary storage provides non-volatile, long-term storage for data and programs when the computer is switched off. It is not directly accessed by the CPU as main memory is; data must first be loaded into RAM. Magnetic storage, such as a hard disk drive, stores data by magnetising tiny areas on a spinning platter, with read/write heads detecting or changing the magnetic state. Optical storage, such as a CD, DVD or Blu-ray disc, stores data as pits and lands on a reflective surface; a laser beam is reflected differently by pits and lands, and the pattern is interpreted as binary. Solid state storage, such as a USB flash drive or solid-state drive, stores data in flash memory chips using electrical charge in floating-gate transistors; there are no moving parts. Each method has different characteristics of speed, capacity, durability and cost, but all provide non-volatile storage. A strong answer earns marks for these points. Secondary storage is non-volatile and used for long-term storage of data and programs. Secondary storage is not directly accessible by the CPU; data must be transferred into main memory (RAM) before it can be processed. Magnetic storage stores data by magnetising areas of a magnetic medium, for example a spinning platter in a hard disk drive, and read/write heads detect or change the magnetic state. Optical storage stores data as pits and lands on a reflective surface; a laser reads the pattern of reflections as binary. A common slip: Thinking secondary storage is directly accessed by the CPU. Instead, stating that data must first be copied into RAM before the CPU can use it. Exam tip: For multiple-choice questions, match the storage technology to its method: magnetic – magnetised areas; optical – pits and lands read by laser; solid state – electrical charge in flash memory.
Key words
Say what each word means before you turn the card.
role of secondary storage
Try answering aloud or in your head before turning the card.
magnetic storage method
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optical storage method
Try answering aloud or in your head before turning the card.
solid state storage method
Try answering aloud or in your head before turning the card.
See every definition
- role of secondary storage
- Provides non-volatile, long-term storage for data and programs when the computer is switched off, and is not directly accessed by the CPU.
- magnetic storage method
- Stores data by magnetising tiny areas on a spinning platter, with read/write heads detecting or changing the magnetic state.
- optical storage method
- Stores data as pits and lands on a reflective surface, where a laser beam is reflected differently and the pattern is interpreted as binary.
- solid state storage method
- Stores data in flash memory chips using electrical charge in floating-gate transistors, with no moving parts.
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