Wednesday, 29 October 2014

Secondary Storage Devices


Secondary Storage Devices:-

Secondary storage devices are used to store data Permanently. The data on secondary storage devices can be shifted from one computer to another computer easily.
It has three types.
Magnetic Disk
Magnetic Tape
Optical Disks

Magnetic Disk

            It is most widely used storage media for all type of computer. A magnetic disk is a thin circular metal plate or platter coated with magnetic material. Information can be record on or read from the magnetic surface through magnetism. Magnetic disk is a random access storage media.
Types of Magnetic Disk
There are the following types of the magnetic disk
  1. Hard Disk 
  2. Floppy Disk 
  3. Zip Disk 
  4. USB flash Drive

Magnetic Tape (Sequential Access)

It is an example of old type storage media to store large amount of data permanently. Magnetic Tape consists of a thin ribbon of plastic. The tap is coated with magnetic material. The process of reading or writing of data on the tape is very slow. In magnetic tape, data can only be accessed sequentially. It is mostly used for taking backup of data.

Optical Disks

Optical disk issued laser technology to read or write information. LASER Stands for Light Amplification through stimulated emission of Radiation Laser beam is used to make tiny holes on the surface of the disk. 

Compact Disk (CD)

CD is the most popular optical medium. It can hold 650 MB to 800 MB of data. The data on the CD cannot be erased like magnetic diskettes. 

DVD

DVD, also known as "Digital Versatile Disc" or "Digital Video Disc", is an optical disc storage media format. Its main uses are video and data storage. DVDs are of the same dimensions as compact discs (CDs), but store more than six times as much data