This research is concerned with developing new modulation, detection, and coding systems for increasing the density of reliable digital data storage and retrieval on magnetic media. In order to design better and more efficient signal processing systems a thorough knowledge of the signal and noise characteristics of the storage channel must be obtained. Thus experimental data will be collected to better characterize the input-output characteristics of the channel. In particular, emphasis will be placed on measuring effects that occur at high recording densities, e.g., signal nonlinearities. Based on these measurements, mathematical models will be developed which describe the input-output characteristics of the channel. These models will be used to suggest improved modulation, detection, and coding systems. The performance of these systems will be evaluated based upon these models and compared to alternative systems.