What is magnetic disks?explain it?

Magnetic disk provides the bulk of secondary storage of modern computer system. The disk capacity is growing at over 50% per year. But the storage needs of large applications have also been growing very fast and in some case each faster than the growth rate of disk capacities. A large data base may need 100 of disks.

Physical characteristics of disk

Physical disks are relatively simple. Every disc platter has a flat circular shape

We can call magnetic disk as

Ø   hard disk

Ø   Floppy disk

The read write head keeps information on a sector magnetically as reversals of the direction of magnetization of the magnetic material. There might be hundreds of concentric tracks on a disc surface, having thousands of sectors.