Now, even 1-Gbyte drives are too small. To keep up, builders of hard drives are searching for ways to cram more bits into less space. It relies on familiar magnetic media, yet promises to boost storage densities from today's 700 Mbits per square inch to the 5-10 Gbits needed by the turn of the century. Conventional hard drives depend on the close relationship between electricity and magnetism. If electrical current is sent through the coil, it creates a magnetic field.
Floppy drives are a simple example of magnetic storage.
The floppy itself is a sheet of plastic with millions of tiny metal shards stuck to its surface. The drive spins the disk while two very small wire coils, called heads, rest on the top and bottom surfaces. Since hard drives retrieve data faster, the platters must spin faster. To write data to the disk, a drive sends current through one of the coils, switching it on and off to represent the 1s and 0s of the data stream. The magnetic field induced by the current pulls the magnets on the surface of the disk into alignment, storing the data bits.