1.10 Secondary storage Devices

The secondary storage device is a storage medium used for storing data, instruction and output for archival purposes, so that whenever any data or instruction is required in the future, it can be retrieved for reference, or for further processing. Different kinds of secondary storage devices available are:

1)      Floppy Disk: A floppy disk is a circular plastic disk coated with magnetic oxide and enclosed within a square plastic cover. The data or instruction is stored in the form of magnetic impulses. The floppy disks are available different sizes, but the most commonly used floppy disks are 51/4” and 31/2”.

2)      Hard Disk: A hard disk is a storage device that contains one or more rigid disks called platters coated with magnetic material sealed in an enclosure. It is most often called a fixed disk as it is placed within the cabinet of the computer system, and cannot be removed often like the floppy disks. The storage capacity of the hard disk is more than a floppy disk. The data is stored in the form of magnetic impulses.

3)      Optical Disk: An optical disk uses Optical Technology (LASER) to store and retrieve data. The amount of data that can be stored on a single disk is enormous. However, it faces only one drawback and that is, once recorded, it cannot be modified or removed, but can be read as many times as you wish i.e. WORM (Write Once Read Many times).

4)      Cartridge Tape: A cartridge tape is magnetic storage medium, but the only difference is data is stored on a tape and not on a platter. It resembles the audio cassettes and generally uses in microcomputers.

5)      Spool Tape: A spool tape is again a similar storage medium as compared to your cartridge tape. But has a comparative higher capacity of data storage and size if compared to the cartridge tape. They are generally used in minicomputers and mainframes.