an intelligent hard disk drive subsystem including control circuitry and disk drive storage media along with drive mechanics in a combination including a standardized interface between the intelligent subsystem and a host computer wherein the data is buffered , serialized , deserialized , conditioned , precompensated , and located within the media , all under the control of a microprocessor within the subsystem . a method of formatting the media is provided which eliminates the need for a track 0 sensing switch , and which provides for formatted guard bands on the disk . the formatting process locates the head through a sequence of writing , indexing , and reading , until a stop is located by the fact that the head reads what it has just written .