| abstract |
A magnetic disc storage system employing two stage actuators for simultaneously positioning recording heads over the top and bottom surfaces of the disc is disclosed. The recording heads are fastened to a distal end of respective top and bottom load beams. A base end of the load beams is connected to a voice coil motor (VCM) rotary actuator which simultaneously positions both recording heads over the disc. A silicon microactuator is also fastened to the distal end of at least one of the load beams for positioning the recording heads independent of one another, thereby allowing simultaneous tracking of embedded servo data. Various data formats are provided, including interleaving logical sector numbers, symbols of a logical sector, and segments of a logical sector, between the top and bottom physical sectors of a track. Complexity and cost of the servo controllers is reduced through the use of sliding mode control: a simple, robust and fast control system implemented using simple switching circuitry, small lookup tables, and simplified binary multipliers (shift registers). A dual path read channel implemented in a single integrated circuit is provided for parallel processing the read signals from the top and bottom recording heads. |