Secondary Storage

It's also known as an Auxiliary Storage. It is a non-volatile device that holds data until it is deleted or overwritten. Such memories tend to occur in two types-sequential access (data must access in a linear sequence) and direct access (data may access in any sequence). The most common sequential storage device is the hard disk drives, whereas direct-access devices include rotating drums, disks, CD-ROMs, and DVD-ROMs. It used as permanent storage of data in mainframes and supercomputers.

Optical Storage
 is any storage method that uses a laser to store and retrieve data from optical media. The data is stored in a pattern of DOTS.

Fig 1.1 Optical Storage

Types;

1. Read-Only Optical Discs. Read-only optical discs have data written onto them when they are manufactured. This data cannot be changed.
2. High Capacity Optical Discs
3. Recordable Optical Discs

 Examples;
CD-ROM
DVD-ROM
Blu-Ray
HD DVD
CD-R
CD-RW etc

Magnetic Storage
Magnetic storage media and devices store data in the form of tiny magnetised dots. These dots are created, read and erased using magnetic fields created by very tiny electromagnets. It is a form of non-volatile storage.

Fig 1.2 Magnetic Storage

Types

Hard Drives. Fixed hard-drives act as the main backing storage device for almost all computers since they provide almost instant access to files (random access and high access speeds.

Magnetic Tape. Magnetic tape is a large capacity, serial access medium. Because it is a serial access medium, accessing individual files on a tape is slow.

Removable Media Magnetic Disc

Examples;

Portable Hard drive

Zip Disc

Floppy Disc

Solid Storage
It's any storage media that stores data and has no moving parts. It's often made from silicon microchips. Data is stored on Solid Storage electronically.

Fig 1.3 Solid Storage

Examples

Flash Memory

Memory Cards

Smart Cards


Sources

• “What Is a Secondary Storage Device?” Computer Hope, 29 Dec. 2017, www.computerhope.com/jargon/s/secostor.htm.
• “Magnetic Storage Devices / Media | IGCSE ICT.” IGCSE ICT - Magnetic Storage Devices / Media | IGCSE ICT, www.igcseict.info/theory/3/mag/index.html.