Secondary Storage

KEY WORDS:

Magnetic Storage Technology - Using material with magnetic properties (ability to change polarity to store data)

Optical Storage Technology - Using reflective materials to store data by burning ‘pits‘ and leaving ‘land‘. Data is read by shining a laser and seeing which elements reflect and which do not.

Solid State Storage Technology - Using circuitry, which traps electrons in specific orders in order to store data.

MAGNETIC STORAGE:

• Magnetic storage uses different patterns of magnetisation in a magnetisable material to store data (tape/hard disk).

• Magnetised points on a pattern represent ‘1‘ and demagnetised points represent ‘0‘.

Characteristics:

1. Large capacity

2. Cheaper cost per gigabyte compared to Solid State.

3. Small and portable

4. Well-protected and durable

5. Slower access speed than solid state but faster than optical storage

Facts:

• Floppy disks are an obsolete type of magnetic storage.

• Floppy disks have been replaced by USB sticks (solid state storage device) which are much faster and high capacity.

• Magnetic tape is still used by companies to back up or archive large amounts of data.

• It has a large storage capacity.

OPTICAL STORAGE:

• Optical storage consists of ‘marks‘ arranged in patterns.

• When writing to optical media, the light (laser) is shined on its surface.

• When it hits land, the beam reflects (0) but when it hits the pits, it doesn’t reflect(1).

Characteristics:

1. Low capacity

   • CD - 700MB

   • DVD - 4.7 MB

   • Blu-ray - 25GB

2. Not durable - can be scratched and broken easily

3. Fragile

4. Thin and portable

5. Cheap to buy in bulk

6. Slowest access speed

Facts:

• Uses lasers to project beams of light onto a spinning disc to allow data to be read.

• Slowest of the four types of secondary storage.

• Traditionally internal but external disc drives can be bought for devices like laptops.

• Magnetic disks are spelt with a ‘k‘, and optical discs are spelt with a ‘c‘.

SOLID STATE STORAGE(flash):

• Work by sending a large electric current to force electrons through a barrier and trapping them in position.

• The flash of electric current used to achieve this gives us the name for this type of memory.

• The different arrangements of electrons gives us data.

Characteristics:

1. More expensive cost per gigabyte than magnetic

2. Usually durable but cheap USB sticks can snap or break

3. Small and portable

4. High capacity

5. Fastest access speed because they contain no moving parts.

Facts:

• Solid state drives are replacing magnetic hard disk drives in modern computers and video game consoles because they’re quieter, faster and use less power.

• USB flash drives(USB sticks), SD cards or micro SD cards are types of solid state storage.

NETWORK ATTACHED STORAGE(NAS):

• Stand alone external hard drive at the centre of a network. Plugs into the network to allow users of different computers to write or read files, usually documents and media files.

CLOUD STORAGE(ONLINE STORAGE):

• Used to store documents and media files online. This means that you can go to another computer and access your files(providing you have internet access)