High capacity submicro-winchester fixed disk drive

Abstract

A miniature disk drive achieves storage densities of at least approximately 1700 tracks per inch per storage surface of a storage disk defining a series of radially extensive servo sectors embedded within circumferential zones of data tracks. The sectors are recorded at a constant data transfer rate while each zone has a data transfer rate adapted to disk radius. The drive includes a head and head positioner, a read preamplifier for amplifying analog signals read from, and for amplifying signals to be written to, a storage surface. A circuit board carries drive electronics including a read channel, a servo processing circuit for recovering head location information from the servo sectors, a data block sequencer for sequencing data blocks between a buffer and the storage surface, a buffer memory controller for controlling the buffer, a bus level interface circuit for transferring data blocks between the buffer and a host computer, and a programmed digital controller which functions within a head position servo loop and which also controls the sequencer, buffer controller and bus level interface circuit. As one feature, the servo sectors split data blocks into segments. Segment byte counts in each data block header are used by the sequencer automatically to assemble the segments into data blocks during read and to divide the blocks into segments during write. A single VLSI circuit including the sequencer, servo processing circuit, memory controller and an interface to the microcontroller is disclosed.