Discuss the mechanism to read data from and write to a disk?
Disk read/write heads are mechanisms in which read data from or write data to disk drives. The heads have gone by a number of changes over the years.
In a hard drive, the heads 'fly' above the disk surface along with clearance of as little as 3 nanometres. The "flying height" is constantly decreasing to enable higher field density.
The flying height of the head is controlled through the design of an air-bearing etched onto the disk-facing surface of the slider. The role of the air bearing is to manage the flying height constant as the head moves over the surface of the disk. If the head hits the disk's surface, a catastrophic head crash can result.
The heads themselves begin out same to the heads in tape recorders-easy devices made out of a tiny C-shaped piece of highly magnetizable material known as ferrite wrapped in a fine wire coil. While writing, the coil is energized, a strong magnetic field forms within the gap of the C, and the recording surface adjacent to the gap is magnetized.
While reading, the magnetized material rotates past the heads, the ferrite core concentrates the field, and a current is produced in the coil. The gap where the field is extremely strong is quite narrow. That gap is roughly equal to the thickness of the magnetic media on the recording surface. The gap denotes the minimum size of a recorded field on the disk. Ferrite heads are large, and write fairly large characteristics.