A DATA STORAGE DEVICE AND A METHOD OF DATA STORAGE

A data storage device and method are described. The device includes a base (11), a plurality of rigid magnetic data storage disks (12, 14, 16, 18) commonly journalled to the base, one disk surface being divided into a plurality of radial sectors, each sector being recorded with first bursts offset from track centreline in a first direction for odd numbered tracks and a second direction for even numbered tracks, and with second bursts between the first bursts offset from track centreline in the second direction for odd numbered tracks and centreline in the first direction for even numbered tracks; a plurality of read/write data transducers (42, 44, 46, 48, 50, 52, 54, 56) held in close proximity to the disks; a carriage carrying the transducers; optical encoder means (94, 88, 96) for providing a plurality of phase related signals indicating transducer position relative to the base; peak detection means for detecting and putting out average peak amplitude values for each sector servo burst read by the associated transducer; analogue switch means for switching between the said position signals and peak amplitude values; analogue digital converter means for converting each analogue signal received therefrom into a digital word; user interface circuit means for receiving digital disk surface and track selection control data; tachometer means for generating clock signals representing sector boundaries; programmed digital microprocessor means for receiving digital data from the analogue to digital converter means and the user interface circuit means to calculate control data for commanding the actuator to move from a departure track to a user defined destination track on information from the encoder means during track seeking, and for commanding the actuator to maintain the transducers in track centreline alignment on information from the peak detection means during track following; digital to analogue converter means for receiving and converting the said control data words into analogue signal values; and amplifier means for amplifying the analogue signal values to control the carriage means during track following and during track seeking and settling.