Abstract: A read/write preamplifier circuit is provided that includes a fault detecting circuit that detects when two or more read/write preamplifiers are concurrently selected for communicating with their associated data heads and means for notifying the drive controller of that condition. In one embodiment of the invention, the means for notifying the drive controller that two or more preamplifiers are concurrently selected includes a data storage register that is readable by the drive controller and that has a fault flag which is set when two or more preamplifiers are concurrently selected. Also, in one embodiment, the fault detecting circuit includes a fault-detect transistor that drives a predetermined current if the preamplifier is elected. The collectors of the fault-detect transistors of each preamplifier are electronically coupled to each other and to a sensing circuit that senses if the fault-detect transistors of two or more preamplifiers are concurrently driving the predetermined current.

Abstract: A slider assembly for selectively altering a position of a transducing head with respect to a track of a rotatable disc having a plurality of concentric tracks includes a slider body having a main portion and a head portion separated by a gap. The head portion carries the transducing head. The slider body is arranged to be supported by a support structure over a surface of the rotatable disc. A pair of structural elements are disposed on opposite side surfaces of the slider body between the main portion and the head portion across the gap. At least one of the structural elements is a microactuator responsive to electrical control signals to selectively bend to alter the position of the head portion with respect to the main portion of the slider body. The structural elements may be complementary microactuators.

Abstract: A spacing between a transducer head and disk surface in a disk drive's head-disk interface is monitored. The transducer head includes a magneto resistive element. The surface of the disk includes a region containing at least one asperity extending from the surface to have a height. The transducer head is placed over the region containing the at least one asperity, and the disk is rotated. A determination is then made as to whether the transducer head contacts the at least one asperity.

Abstract: A method and apparatus for releasing an actuator from a latched position. A voice coil motor is operably coupled to the actuator which is held by a latch in a latched position. The voice coil motor is provided with a first current signal of increasing magnitude alternating with a second current signal out of phase with the first current signal. The first current signal causes the voice coil motor to urge the actuator away from the latched position, and the second current signal causes the voice coil motor to urge the actuator towards the latched position.

Abstract: A disk drive manufacturing system and process which includes head to disk interference equipment, servo writing equipment, formatting and controlling firmware. The system servo writes a varying number of data tracks per disk surface while sensing when the head is positioned over the transition and/or landing zones of the magnetic disk surface. The servo writing of tracks continues as far as possible on each disk surface, and stops just before the transition zone region of the landing-zone is encountered. Each disk processed has a varying number of data-tracks per surface, which variable data-track information is factored and utilized in a further step of formatting the disk in accordance with the changed boundaries of the data zone and in accordance with instructions received from a disk drive's formatting and controlling firmware.

Abstract: A method of determining the subtrack within zone P on a recording medium is provided. The recording medium has a plurality of zones 1 through Q. Each zone has a plurality of subtracks 0 through M. Each subtrack has a plurality of sectors 0 through N. Each sector has a position identifier field. Each position identifier field has a plurality of information units for recording a position identifier. The position identifier for Jth sector of subtrack I is identified as S(I,J). A preferred method comprises obtaining the local subtrack value as S(I,0), a space-efficient way to store and extract subtrack location information.

Abstract: An improved locking system for securing the actuator of a disc drive at a park position. The locking system includes a rotatable lock mechanism that is normally biased to a lock position. When the actuator is moved to the park position, a cooperative lock feature on the moving portion of the actuator interacts with a pawl feature on the rotatable lock mechanism to momentarily overcome the biasing force. When the lock feature on the moving portion of the actuator moves beyond the pawl feature, the bias force acts to return the rotatable lock mechanism to its locked position with the pawl feature engaging a cooperative surface on the lock feature to lock the actuator at the park position against a lightly compressed compliant limit stop and to maintain the actuator at the park position in the presence of applied mechanical shocks.

Abstract: Servo-pattern information is magnetically recorded on a product disc by magnetic print-through from a master medium. The master servo-writing medium is brought into close proximity with the product “slave” disc, and the two are subjected to an external magnetic field which assists in transferring magnetic servo-patterns to the slave disc in a print-through process. The preferred external magnetic field alternates and rotates with respect to the master/slave combination. In an alternative product disc structure, the magnetic layer is magnetically altered in a servo-pattern configuration. Non-magnetic portions of the servo pattern are created which define both gray code and servo burst information for the product disc.