Secondary Storage Devices

The main advantage of secondary storage device over primary storage device is that secondary storage devices can store data permanently when the computer is turned off. These are the devices that are used to store the data permanently for the future reference.

Magnetic Storage Device
Magnetic Storage devices uses a surface coated with a magnetically sensitive material, such as iron oxide, chromium oxide etc. which react to the magnetic field. The orientation of the magnetic field can be used to represent data. When a binary 1 is to be stored, the information is sent to the head, and it magnetizes a spot below with left to right pole alignment S->N. Similarly the binary 0 is stored with right to left pole alignment N<-S.

The disk has to be formatted before using. This creates a set of magnetic concentric circles called tracks and each track on a disk is also split into smaller parts known as tracks.

The following are the types of secondary storage devices.

1. Hard Disk
A rigid magnetic disk fixed permanently within a drive unit and used for storing computer data. Hard disks generally offer more storage and quicker access to data than floppy disks do.

2. Memory Card
A memory card or flash memory card is a solid-state electronic flash memory data storage device used with digital cameras, handheld and Mobile computers, telephones, music players, video game consoles, and other electronics.

3. Pen Drive
The pen drive is a portable USB flash memory device that can be used to quickly transfer audio, video, and data files from the hard drive of one computer to another.

4. Magnetic Tape
Magnetic tape is a memory device consisting of a long thin plastic strip coated with iron oxide; used to record audio or video signals or to store computer information.

Utilized as a storage device since the early days of radio, magnetic tape is an external storage device that can be used for making copies of audio, video, and data. In addition to data storage, magnetic tape has been used over the years to make master copies of audio recordings that would be replicated for cassette, and more recently compact disk recording formats.