Backing Storage

Hard Disc Drive (HDD)
A HDD is a storage device that uses magnetism to store digital data, it uses either a single or multiple platters (magnetic disks) where you can read/write data to by using an actuator arm with read/write headers as the platters rotate at high speeds. It is stored in different patterns of magnetisation to store digital data (Magnetised - 1 Non-Magnetised – 0) in a magnetisable material.

Solid State Drive (SSD)
SSDs contain no moving mechanisms to read/write data but instead uses flash memory to store information, they are non-volatile so they don’t require power in order to retain data. SSDs are capable of much faster speeds when compared to HDDs as data can be instantly read/written instead of waiting for the actuator arm and disk rotation to in the correct position.

Optical Disk Drives (ODD)
Optical drives store data on disks by using a laser to burn data onto a disk and later read the marks burned onto the disc as digital information. There different formats of optical disks are CD, DVD and Blu-ray with the main difference been the size of the laser used to read/write data with a smaller laser been capable of burning physically smaller bits to the disc.
 * CD - 0.7 GB.


 * DVD - 4.7GB.


 * Blu-Ray - 25GB