Computing - Storage Devices
AQA Computer Science 2022
See Also
Flashcards
Drives, media and optical storage
What is a drive?
A device that reads and writes data from secondary storage.
What is the main principle of operation of optical storage?
Processing the reflections caused by shining a laser at pits and lands.
How are read-only optical storage devices (such as CD-Rs) initially written to?
A laser burns pits and lands.
How are read-write optical storage devices (such as CD-RWs) written to many times?
With a reversible chemical reaction.
In what direction is the data on an optical storage device read?
Spiralling from the inside-out.
What are some advantages of optical storage devices?
- Cheap
- Light weight
- Portable
What are some negatives of optical storage devices?
- Slow access times
- Prone to scratches
Magnetic media
What is data actually represented as in magnetic storage?
Small regions that can be magnetised or demagnetised.
What makes tape worse than magnetic hard disks despite having more storage capacity?
Read/write times are very slow.
Solid-state media
How do solid-state drives store information?
As charges trapped in a floating gate between two oxide layers.
How do solid-state drives write information?
Running electrons past oxide layers.
What are some advantages of solid-state storage?
- Durable
- Fast access times
What are some disadvantages of solid-state storage?
- Expensive
- Limited reads and writes