What is Magnetic Disk and Floppy Disk?

2.2 Magnetic Disk

Magnetic disk is the most widely used storage media. A magnetic disk is a thin, circular metal/platter coated with magnetic material. Information can be recorded on or read from the magnetic surface. A disk must be formatted before it can be used. The formatting process prepares the disk so that it can store data.

Formatting is a process that creates tracks and sectors on disk. Each track on a disk is divided into sectors. Each sector holds a specific number of characters. A sector is the smallest physical storage unit on a disk. Its size is normally 512 bytes. Two or more sectors combine to form a cluster. A cylinder consists of all tracks of the same number. Every cylinder contains the same number of sectors. For example, track 0 of slide 1 and track 0 of side 2 is called cylinder 0.

The magnetic disk is a random access storage media. It means that any part of the disk is directly accessible. Three types of magnetic disks are floppy disk, hard disk and Zip disk.

2.2.1 Floppy Disk or Diskette

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 introduce by IBM in early 1970s. It is a portable storage medium and can be removed from one computer and inserted into another computer easily. It is not very popular now a days.

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 disks 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 the floppy disk drive is used to read and write data on the floppy disk. Floppy disk drives are downward compatible. It means they can use earlier media.

The storage capacity of a diskette depends on the following two factors:

·         Destiny: It is the number of bits that can be stored on one inch. It is measured as bits per inch (bpi). A floppy disk with higher density can store more data.

·         Number of Tracks: The number of tracks on a diskette is measured as tracks per inch (tpi). A floppy disk with more tracks can store more data.

Floppy disk was being used too much earlier times. But now its usage is lesser in today's life because its alternatives and best storage devices are available in market. As we know that we always seek for best things that can help us. Floppy disks contain lesser data I think this is the main reason for which people do not use it in these days.