Backing Storage

Backing Storage

Computers need backing storage because data in main memory is lost when the computer is switched off.

Backing storage is used to store programs and data permanently.

Backing Storage

Hard Disk

Magnetic disk

Typical storage: 500Gb – several Tb

Backing Storage

CD-ROM

Optical disk, uses laser to read

Typical storage: 650Mb

Backing Storage

DVD

Optical disk, uses laser to read

Typical storage: 4.7Gb

Backing Storage

Solid State Drive

Data stored on microchips, faster (and more expensive) than Hard Disk Drive

Typical storage: Up to 1Tb

Backing Storage

USB Flash Drive

Data stored on microchips but not as fast or reliable as SSD

Typical storage: Up to 1 Tb

Backing Storage

Backing Storage Media

Sequential orRandom

Magnetic Tape Is mostly used for backing up data, all storage locations are one after the other.

Sequential

Hard Disk RandomCD-ROM RandomDVD-ROM RandomCD RandomCD-RW Rewriteable CD allows the user to record

over data or delete individual files.Random

DVD-R RandomDVD-RW RandomUSB Random

Backing Storage

Sequential vs Random Access

Sequential

Random