Abstract: One embodiment of the present invention is directed to a method of aligning servo wedges of a plurality of disc surfaces in a disc drive. This process of aligning servo wedges in a disc drive includes writing multiple servo wedges, one adjacent another, continuously across an entire circumference of each disc surface. Subsequently, one of the disc surfaces is designated the master surface. Every nth servo wedge on the master surface is then designated as a master wedge, where n is a positive integer. Next, the servo wedges on the non-master surfaces which are most closely axially aligned with the master wedges are selected. Subsequently, all of the non-selected and non-master wedges are erased.

Abstract: A hard disc drive having a digital servo system for controlling the position of a servo head on a dedicated servo surface. The servo surface is formatted in a series of consecutive frames along concentric tracks, each frame passing the servo head in a time that defines a sampling interval for the servo system. The frames contain track address and position fields for locating the servo head and location can be effected in relation to limited or extended fine control regions about the tracks via signals transmitted to a position circuit utilized to generate a servo position error from the position field. The position circuit generates a track phase code for checking track addresses generated by a track address circuit used to generate a track address from the address field.

Abstract: A circuit for slimming signals read signals from a read/write head of a rotating disk data storage device. A low-pass filter and a high-pass filter are connected in parallel to the read signal from the read/write head. These filters each have a variable gain amplifier connected to their respective output ports. The gain of each of the variable gain amplifiers is programmably adjusted in accordance with preselected criteria. A summing circuit is connected to the outputs of the variable gain amplifiers to generate a slimmed read signal. A multi-pole low pass filter has an input port coupled to the output port of the summing circuit.

Abstract: A circuit for slimming signals read signals from a read/write head of a rotating disk data storage device. A low-pass filter and a high-pass filter are connected in parallel to the read signal from the read/write head. These filters each have a variable gain amplifier connected to their respective output ports. The gain of each of the variable gain amplifiers is programmably adjusted in accordance with preselected criteria. A summing circuit is connected to the outputs of the variable gain amplifiers to generate a slimmed read signal. A multi-pole low pass filter has an input port coupled to the output port of the summing circuit.

Abstract: An index pulse generator in a magnetic storage system reads data from a surface in the magnetic storage system and produces an index pulse. An incrementing sequence of non-zero codes, with redundancy, is written in a series of consecutive servo data frames, immediately preceding, leading up to, and including a specific servo index frame. Error tolerant circuitry reads and decodes the servo frame data, maintains a count of non-zero codes encountered, and generates an index pulse provided that both the desired count of non-zero codes has been reached and that a minimum number of matches between the non-zero frame counter and the actual frame decodes has been satisfied.