Secondary Storage: Computer Science OCR: GCSE (9:1)

Secondary Storage

Non-volatile storage that stores programs and data. The OS, system software and application software are all installed here, plus files and folders. Comes in many types: magnetic, solid state and optical

Optical

A type of secondary storage that uses laser light to burn data onto a medium such as CD, DVD or Blu-Ray disc

Magnetic

This secondary storage type stores data by magnetising the surface, it includes hard disk drives and tape drives

Solid state

Secondary storage type with no moving parts, it uses semiconductor technology, and works by trapping electrons inside a gate. Includes SSDs, flash memory, memory sticks and SD cards

Capacity

The amount of data that can be stored in a storage device or on storage media. If you create lots of data you need this characteristic to be high

Speed

How fast data can be read from or written to a storage device. This characteristic is important if your application creates or uses a lot of data quickly such as a video camera

Portablility

How easy it is to carry around a storage device or its media. You need this characteristic for secondary storage in smartphones, laptops and tablets

Durability

How well it survives knocks and drops. A device that is carried around a lot needs this characteristic to be good

Reliability

How long a device will last without losing data. Devices with moving parts like HDDs are low in this characteristic

Cost

How expensive a device is. Some devices are faster and more durable but that makes this characteristic higher

Volatile

Loses its contents when switched off, this describes main memory aka RAM. Because data in RAM is not permanent, we need secondary storage.

Non-volatile

Retains its contents when switched off, like all secondary storage so we can save data and install programs permanently