Considerations for applying solid state sensors to high density magnetic disc recording

To compete with optical recording densities of 10
⁷
or greater bits per square centimeter, equal magnetic disc areal densities must be achieved. Based on signal to noise considerations, inductive sensing of magnetic transitions written on magnetic media must give way to solid state magnetic sensors. There are fundamental considerations involved with implementing solid state sensors as read heads. These considerations embrace the basic sensor characteristics of size, resolution, sensitivity, signal to noise ratio and frequency response. Other equally important considerations involve packaging and head-wear resulting from head-media proximity demanded by the nature of the field to be sensed from the media. Finally, the solutions to these considerations must be simple and inexpensive.