Secondary Storage: Solid State & Magnetic Flashcards
All 14 cards in this deck
What is secondary storage?
Any non-volatile storage that is not directly accessible by the CPU. It keeps data, files and programs long term, including when the computer is switched off.
Why does a computer need secondary storage?
Because RAM is volatile and limited in size, so data and programs must be stored permanently somewhere with a large capacity.
What are the two main types of secondary storage in a modern computer?
Solid state (e.g. a solid state drive, SSD) and magnetic (e.g. a hard disk drive, HDD).
Give two examples of magnetic storage devices or media.
Hard disk drive (HDD) and magnetic tape.
Give two examples of solid state storage devices or media.
Solid state drive (SSD) and USB memory stick (also SD/memory cards).
How does solid state storage store data?
It uses electrical circuits (flash memory) to store data persistently. It has no moving parts, and keeps its data when the power is off.
True or false? Solid state storage contains moving parts.
False. It has no moving parts, which makes it robust and portable. A solid state drive (SSD) is also faster to read from and write to than a magnetic hard disk drive.
Give one advantage and one disadvantage of a solid state drive compared with a magnetic hard disk drive.
Advantage: faster access with no moving parts, so more durable and lower power. Disadvantage: higher cost per gigabyte.
Why is flash (solid state) memory suitable for tablets, smartphones and digital cameras?
It is small and light, has no moving parts so is robust, uses little power and is fast to read from and write to.
Which type of storage is most suitable for backing up very large amounts of data as cheaply as possible?
Magnetic storage (hard disk drive or magnetic tape) — large capacity at a low cost per gigabyte.
Which typically has the larger capacity, an HDD or an SSD?
An HDD.
What limits the lifespan of the flash memory in an SSD?
It can only be rewritten a limited number of times before it starts to wear out.
How does a magnetic hard disk drive store data?
On spinning platters coated in magnetic material. A read/write head on a moving arm magnetises tiny areas in one of two directions, which represent 0 and 1.
How does a magnetic hard disk drive read data?
As the platter spins, the read/write head moves to the right position and detects the direction of magnetisation of each tiny area beneath it, giving the 0s and 1s.