Sector servo system for high speed seeking and high track density

A microprocessor-based sector servosystem, which uses servo information derived only from each data surface, has been developed. Applying this servosystem to a 5.25-in hard disk drive, a 12-ms average seek time (at 1500 TPI) and +or-0.5- mu m head-positioning accuracy were achieved. The system controls the read/write head position more swiftly and accurately then in conventional head-positioning systems with a dedicated servo surface.<>