Abstract: An improved disc clamping system for the elements of the disc stack in a disc drive to increase resistance to radial shifting of the disc stack elements. The increased resistance to radial shifting is achieved by increasing the coefficient of friction between adjacent disc stack elements, and the increase in the coefficient of friction is accomplished by controllably texturing the contact surfaces of various disc stack elements or combinations of disc stack elements. Surface texturing processes particularly suited to specific disc stack elements are disclosed.

Abstract: A disc pack assembly is provided for use within a disc drive having a spindle motor assembly rotatable about a central axis, with a spindle hub and a hub flange. A disc centering sleeve of the current invention with an inner raised portions and outer raised portions is placed around the spindle hub. An information storage disc is stacked on the spindle hub and rests on the hub flange. A disc spacer is placed on top of the information storage disc. A disc clamp is used to secure the information storage disc to the spindle hub. The inner raised portions abut against the outer surface of the spindle hub and the outer raised portions abut against the inner surface of the information storage disc and the disc spacer, centering the information storage disc and the disc spacer concentric with the central axis.

Abstract: A latching mechanism for a disc drive actuator that makes use of a constant force to hold the latch in an unlatched position while the disc drive is in operational mode. The latching mechanism uses the power of the actuator to move the latching mechanism into a latched position under program control or upon the detection of a power loss. While in the latched position, the configuration of the latching mechanism components combined with the frictional contact between heads and discs serves to overcome the constant force and maintain the actuator in its park position, even in the presence of applied mechanical shock, until power is restored to the disc drive. Unlatching of the latching mechanism is accomplished by bringing the spindle motor up to a speed at which the heads begin to fly, eliminating the friction between the heads and discs and allowing the constant force to move the latching mechanism to it unlocked position.

Abstract: A disc pack assembly comprises a spindle motor assembly rotatable about a central axis. The spindle motor assembly has a spindle hub, which has at least one ring receiving portion. At least one information storage disc is stacked on the spindle hub and a resilient spacer ring is stacked on top of the information storage disc. A second resilient ring is located in the ring receiving portion of the spindle hub and is adjacent to the inner diameter of the information storage disc.

Abstract: A method of storing and retrieving P user information data and Q error information data for the P user information data in a buffer memory unit having multiple DRAMs. P user information data and Q error information data together define a paragraph. Each user information data and error information data have a plurality of information units. Each DRAM has a plurality of rows and columns, with a maximum column address of M and each row capable of storing N such paragraphs. The virtual memory address for each user information data is translated by dividing the virtual memory address by N, then assigning quotient of the division as the row address and assigning remainder of the division as the starting base column address for the user information data. To store or retrieve successive user information data within a paragraph, the base column address is incremented from (starting base column address+0) to (starting base column address+P).

Abstract: A disc clamp for securing a plurality of information storage discs to a spindle hub on a disc drive motor assembly comprising an annular inner wall portion, an annular outer ring portion, a plurality of clamp load beams extending radially from the annular inner wall portion to the annular outer ring portion and a plurality of eyelets extending radially from the annular inner wall portion for receiving screws that couple the disc clamp to the spindle hub.

Abstract: A flexure mounting system that facilitates removal of a faulty head/flexure assembly in a disc drive. The flexure mounting system includes an improved mounting plate for head/flexure assemblies in disc drives. The improved mounting plate includes deswaging tabs which extend laterally beyond the width of the actuator head mounting arms to which the mounting plates and attached head/flexure assemblies are mounted. A disassembly tool, configured to operatively engage the deswaging tabs, and a specially featured flex circuit adapted for use with the improved mounting plate are also disclosed.

Abstract: A method of encoding position information for a group of recording units on a recording medium having plurality of primary groups, with each primary group having N primary labels and plurality of secondary groups, with each secondary group having M secondary labels. The primary labels and secondary labels are always in a fixed sequence. The primary labels and secondary labels are combined such that for each position X, there is a unique combination of primary label and secondary label. Further, the value of Xth primary label differs by the quotient of X/N from the value of corresponding secondary label of the secondary group when the value of primary label is greater than or equal to the value of secondary label and the value of Xth primary label differs by M subtracted from the value of secondary label when the value of primary label is less than the value of secondary label.

Abstract: An apparatus for mounting head-supporting flexures in a disc drive includes a transverse hole closely adjacent the distal end of head mounting arms, the transverse hole communicating to the distal surface of the head mounting arm through a transverse slot. Flexures are formed with a substantially semi-cylindrical transverse channel at their proximal mounting ends. A pair of flexures--or a single flexure and a dummy channel blank--are placed in back-to-back relationship such that the transverse channels form a substantially cylindrical transverse opening, and a transverse pin is inserted in the transverse opening. The flexures and pin--or single flexure, dummy channel blank and pin--are then inserted into the transverse hole in the head mounting arm with the flexures extending distally through the transverse slot. The components may be held in their assembled positions by interference fit, or the transverse pin may be deformed after assembly to lock the components in their assembled condition.

Abstract: A method to accurately determine a defective servo burst written on a recording medium having plurality of tracks, each track containing plurality of position data portions. The position data portions include servo bursts capable of providing position error information, which can be selectively retrieved by a servo control system having a servo gate enabling signal. A first likely defective servo burst is identified by reading each servo burst, measuring corresponding position error information and comparing to a range of acceptable position error information. While disabling retrieval from the first likely defective servo burst, the position error information of plurality of servo bursts occurring after the first likely defective servo burst is measured. If the measured values are within the acceptable range, the first likely defective servo burst is concluded as the first confirmed defective servo burst.