List different types of storage devices commonly used in computer. Storage devices are used to store data and programs permanently. These devices are used to store large volume of data and program.

The main reasons for using these storage devices are as follows:

1. Main memory of a computer system is not permanent. This means that data and programs are lost when computer is shut down or power is turned off. Storages devices store data permanently.

2. The main memory of computer system has limited capacity. Storage devices can store a large amount of data.

Storage devices are also called backing storage devices, secondary storage devices or auxiliary storage devices. Following are the types of storage devices:

1.  Magnetic disk

2. Magnetic tape

3. Optical disk

What is magnetic tape? How is data stored on it?

Magnetic tape is an oldest storage media to store large amount of data permanently. Magnetic tape consists of a thin ribbon of plastic. The tape is coated with magnetic material. It is also called read/write device. It reads and writes data sequentially. So its speed is slower than other storage devices.

magnetic-tape

White a note on floppy disk.

Floppy disk is also called diskette. It consists of a thin plastic disk coated with magnetic material. This disk is enclosed in a plastic jacket. It was introduced by IBM in early 1970s. It is a portable storage medium and can be removed from one computer and inserted into another computer easily.

White a note on floppy disk

Floppy disk can only store a small amount of data. Data access speed of floppy disk is slower than hard disk. It is inexpensive storage media.

The standard size of floppy disk is 3 ½ inch. The capacity of floppy disk is 1.44MB. The circular piece of plastic on 3 ½ inch diskette is enclosed in a shell. A piece of metal covers the reading and writing area. It is called shutter. When the disk is inserted into a disk drive, the shutter opens to expose the surface of the disk.

The data stored on floppy disk can be read with floppy disk drive. The read/write head in floppy disk drive is used to read and write data on floppy disk.