It is a smaller capacity removable storage device. It is made up of thin and flexible plastic material. This thin plastic film is coated with a magnetic material known as iron oxide for recording data and is protected by a hard outer cover. It is very useful in transferring data from one computer to another.
Although technology has not changed substantially, floppy disks have certainly changed considerably in order to meet the very demanding needs of the marketplace. From an 8 inch size they have evolved to a much smaller size with larger capacities. Today's standard 3.5 inch diskettes hold a formatted capacity of about 1.44 megabytes. The evolution of the personal computer acted as a catalyst primary for designers to reduce the size and cost of floppies.
Very quickly the floppy became the standard method of exchanging data between personal computers. It also became the popular method of storing moderate amounts of information outside of the computer's hard drive. Diskettes are small, inexpensive, readily available, easy to store, and have a good shelf life if stored properly.
Working of a Floppy Disk
Conventional floppy drives contain the following basic components:
1. A spindle clamping mechanism to hold the diskette in place as it spins
2. Either one or two magnetic read/write heads mounted on a mechanism that moves the heads across the diskette's surface.
3. A sensor that detects the rotational position of the diskette via an index hole (or magnetic sensor in 3.5 inch drives) on floppy disks.
The floppy disk is divided into tracks and sectors. In the adjacent figure, the concentric circles are tracks and the sliced parts of these tracks are called sectors. When the computer system needs to access data on the diskette, the read/write heads are stepped by signals generated by the computer system's floppy controller.
These steps are along invisible concentric cylinders, which are usually referred to as "tracks". The turning on of the computer system's power results in the read/write heads of the drive being automatically set to track 0 (the first track and starting position).
In most drives, this starting position is located by means of a sensor in the drive, which has been adjusted to tell the floppy controller when the heads have reached the first track. If this sensor is not in proper adjustment, then this initial starting calibration is also incorrect and the heads are not properly positioned over track 0. In order to move the heads from this first track to other tracks, the head positioner simply moves in or out one track for each step pulse received from the computer's floppy controller.
