Magnetic and optical storage
Some devices use magnetic or optical storage.
Optical storage makes use of a laser to shine and reflect light to read the data stored. Examples include:
- CDs
- DVDs
- Blu-ray
Magnetic storage makes use of a magnetisable coating. Magnetised dots are made on the surface of the material. These dots are created, read and erased by very small electromagnets. Examples include:
- Magnetic tape
- Hard disk drive
Solid state storage
Modern computer systems, such as mobile phones and MP3 players, all make use of solid state storage devices. These have no moving parts, which means they can:
- Be smaller - devices they are in can be smaller too.
- Use less battery power - devices they are in stay charged for longer.
- Be more robust - a magnetic disk could be ruined by dropping it, because its moving parts may be damaged.
Solid state devices include:
- SD cards, used in mobile phones, smartphones and tablets
- USB flash drives
