Storage Devices and its types?

Storage Devices:
Storage devices are used to store data and programs permanently. These devices are used to store large volume of data. These devices are also called backing storage devices or secondary storage devices.
There are three types of secondary storage devices

• Magnetic Tape
• Magnetic Disk
• Optical Disk

Magnetic Disks
Magnetic disk is the most widely used storage media. A magnetic disk is thin, circular metal plate coated with magnetic material. A disk should be formatted before it is used. Formatting process creates tracks and sectors on disk which is used to hold data.
There are following types of magnetic disk.
Floppy Disk
Floppy disk is also called diskette. It is a small removable disk. It consist of a thin plastic disk coated with magnetic material. This disk is enclosed in rigid plastic jacket. This is inexpensive storage media.
Hard disk
A hard disk contain several disk plates stacked on single rotating spindle. Data is stored on the all surface of platters. The hard disk can contain large amount of data. There are heads which reads and write data. It si more reliable than floppy disk.
Zip Disk
Zip Disk is more portable disk. It is like floppy disk but can stor more data than floppy disks. Its capacity is up to 100 MB.
Flash Drive/Pen Drive/Thumb Drive
Flash drive is more reliable than a floppy disk and can store data than the floppy disk. It has longer lifespan. There is no need to format it.
Optical Disk
Optical disks use laser technology to read and write data on disk. Laser beam write on by creating small pits in the disk.
There are different there of optical devices given below.
CD-Rom
CD-Rom stands for compact disk read only memory. The data stored on the CD-ROm can only be read. It can not be deleted or changed. This is protable device data can be transferred easily by using CD-Rom.
DVD
DVD stands for digital video disk. It is similar to CD-Rom but storage capacity is higher than CD-Rom.
WORM Disk
Worm stands for write once read many. On this type of disk datamay be stored in greater capacity. Once data written can not be changed or deleted.
Rewritable Disk
It is like CD-Rom but data written on this disk may be changed or deleted.
Magnetic Tape
Magnetic tape has been used as a storage devices for a number of years an it remain choice today for high speed and large volume data storage. Its data density is high. Magnetic tape is a plastic ribbon that is coated on one side with iron oxide.