Merchant, Gould, Smith, Edell, Welter & Schmidt
Method and apparatus for controlling and analyzing a data storage system
 A system and method for controlling and analyzing data storage systems, and more particularly, to systems and methods for controlling and analyzing performance and physical attributes of a sealed disk drive unit using an externally accessible but internally integral positioning system. A disk drive having a sealed housing utilizes a reflective planar mirror on the rotary actuator controlling the head drive assembly. A narrow beam directed through a window on the side wall of the housing onto the mirror is reflected off at angle dependent on the actuator position to a beam sensitive detector. A translator system driven by a positioner disposed at a distance from the rotary actuator axis which is substantially greater than the distance between the actuator axis and the head assembly, is used to vary the relationship between the directed and reflected beams. This system incorporates the rotary actuator in a closed loop servo that positions the actuator precisely at different locations relative to the recording medium, so that the data may be written and analyzed at off-track track position increments. The invention further provides, at an early or later manufacturing stage, means for calculating bias torque and friction without the need for prerecorded embedded servo information. 
Servo Track Writer Corporation
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William W. Martyn A. Gajus
Valliant Lewis Michelson