Abstract: Method and apparatus of attenuating an optical signal without adding extra components is presented. The drive current of the optical signal source is set to meet a predetermined bandwidth requirement and exceed a predetermined amplitude requirement. An optical isolator that is used to prevent back-reflections from reaching the optical signal source is used to achieve the desired amount of attenuation. More specifically, the invention includes controlling the attenuation by tuning an angle &thgr; between the transmission axis of a polarizer that is part of the optical isolator and the original polarization state of the optical signal. By increasing the angle &thgr;, the amount of attenuation is increased; by decreasing the angle &thgr;, the amount of attenuation is decreased. The invention allows continuous tuning of the angle &thgr;.

Abstract: The active vibration suppression of a slider suspension arm is achieved by including as part of the suspension arm two bimorph piezoelectric elements. A first bimorph piezoelectric element is attached to the top of the suspension arm and acts as a sensor. A second bimorph piezoelectric element is attached to the bottom of the suspension arm and acts as an actuator. The actuator is controlled as a function of a voltage measured by the sensor so that the actuator damps periodic vibrations occurring in the suspension arm.

Abstract: A combination glide test/burnishing head can be utilized in a glide test/burnishing system. The combination glide test/burnishing head includes two piezo-electric elements, which can be utilized in a passive mode as sensors for detecting contacts between the glide test/burnishing head and asperities on the surface of a magnetic recording disc. Contact between the glide test/burnishing head and disc asperities results in generation of a defect detection signal, which can be utilized by associated test logic to define the location of the detected asperities on the disc surface. The piezo-electric elements of the glide test/burnishing head can also be utilized in an active mode to cause yaw variation in the flight attitude of the glide test/burnishing head, in turn causing a burnishing pad on the glide test/burnishing head to be moved radially into contact with a detected disc asperity.

Abstract: A disk head fly height adjustment method includes positioning a disk head over a surface of a rotating data storage disk and dynamically altering a load point of the disk head by changing an electrical force applied to an active element mounted to a head-gimbal assembly. A data storage apparatus includes a head assembly having a data transfer head coupled to a gimbal and an active element coupling the head assembly and a suspension. The active element is configured to exert a force between the head assembly and the suspension in response to an electrical force applied to the active element. The active element can dynamically shift a load point of a disk head. Shifting the load point can alter the pitch of the disk head and, consequently, the fly height of the head.

Abstract: A magnetic tape head assembly with enclosed through slots to eliminate an air bearing at high tape speeds and lower operating tape tensions is provided. In one embodiment of the present invention, the magnetic tape head comprises a recording gap, containing read/write elements, across the width of the head and slots exposed to the tape head surface that faces the plane of the tape. These slots run through the head approximately perpendicular to the plane of the tape and are open to ambient pressure at a tape head surface other than the surface facing the plane of the tape. These slots are aligned with the read/write elements along the recording gap.

Abstract: A method and apparatus for data disks adapted to compensate for effects of shock loads imparted to a disk drive which are of sufficient magnitude to cause disk shifts. A series of topographical features are formed on the disk surface or edge to cause signal fluctuation in a sensor during read-back mode operation. An initial signal profile is stored as a map indicative of track or disk alignment with respect to the actuator assembly. Selectively, such as after a known shock event, the topographical features are re-profiled. A comparison of the profiles provides a measure of any track distortion which must be compensated for in future read-write operations by adjustments to data track servo follower algorithms.

Abstract: An improved glide head has an air bearing surface with a flatness of less than about 1 &mgr;inch. The air bearing surfaces are formed from the very smooth and flat surface of a wafer, preferably prior to slicing the glide heads from the wafer. Thus, a wafer is formed having a flat surface with a plurality of air bearing surface contoured onto the surface. To form a glide head, a transducer can be mounted on the air bearing surface or the surface opposite the air bearing surface, preferably at the wafer level before slicing.

Abstract: An improved glide head has optical marks on the air bearing surface. The glide heads can be used for detecting defects on disc surfaces following an evaluation of the fly height as a function of disc rotation. The optical marks provide a position for focusing light used in the optical measurement of fly height. The optical marks have measurably different optical properties from the portions of the air bearing surface not covered by an optical mark. The differences in optical properties of the optical marks can be used to adjust the position of the optical system relative to the glide head to ensure that the light is focused on an optical mark.

Abstract: An improved glide head has an air bearing surface with a flatness of less than about 1 &mgr;inch. The air bearing surfaces are formed from the very smooth and flat surface of a wafer, preferably prior to slicing the glide heads from the wafer. Thus, a wafer is formed having a flat surface with a plurality of air bearing surface contoured onto the surface. To form a glide head, a transducer can be mounted on the air bearing surface or the surface opposite the air bearing surface, preferably at the wafer level before slicing.

Abstract: Glide heads for the detection of asperities on a storage disc have a thermal transducer oriented along the air bearing surface. The thermal transducer generally is in electrical contact with a circuit to measure the electrical resistance of the thermal transducer. Preferred methods of depositing the thermal transducer involve the deposition of the thermal transducer on the smooth surface of a wafer prior to the slicing of individual sliders.

Abstract: Cleaning a media surface, such as a disc surface, comprises subjecting the surface to a detector for sensing the nature of the surface for an irregularity in the smoothness of the surface. Directing, on detecting an irregularity beyond a predetermined amount, a burnishing pulse laser output to that irregularity, and energizing the laser to thereby impart an energy source to reduce the irregularity to a degree less than a predetermined amount.

Abstract: A method and apparatus for data disks adapted to compensate for effects of shock loads imparted to a disk drive which are of sufficient magnitude to cause disk shifts. A series of topographical features are formed on the disk surface or edge to cause signal fluctuation in a sensor during read-back mode operation. An initial signal profile is stored as a map indicative of track or disk alignment with respect to the actuator assembly. Selectively, such as after a known shock event, the topographical features are re-profiled. A comparison of the profiles provides a measure of any track distortion which must be compensated for in future read-write operations by adjustments to data track servo follower algorithms.

Abstract: A glide head apparatus for testing surface characteristics of a disc includes a gimbal, a slider and an actuator including a piezoelectric material disposed between the gimbal and the slider. A voltage applied across the piezoelectric material is controllable to cause the piezoelectric material to expand or contract depending on the applied voltage so as to vary the fly height between the slider and a disc under test. The fly height can be varied without substantially varying the linear velocity of the disc under test. Methods of testing surface characteristics of a disc using the glide head apparatus also are disclosed.

Abstract: A magnetic data storage medium includes a dedicated transducing head contact zone for engaging an air bearing slider, primarily when the disk is stationary. The contact zone is textured with at least one elongate ridge extending in the circumferential direction. When a single ridge is formed, it runs in a spiral path in multiple turns with a predetermined radial pitch at least ten times the nominal ridge width. The ridge protrudes axially outward from a nominal surface plane of the contact zone, and is rounded and free of sharp edges. The ridge, or plurality of ridge sections, can be formed by a texturing process that includes directing a laser beam, focused, onto the contact zone surface. While the disk is rotated to maintain a constant circumferential speed relative to the laser, it also is translated radially to provide the desired radial pitch. The laser is operated in a CW (continuous wave) mode, to create a more uniform ridge.

Abstract: A glide test head which includes a pillar or column member positioned on the lower surface of the laterally-extending wing that mounts the piezo element of the glide test head, and extends toward the disc surface being tested. The preferred location of the column member is near the trailing and outermost edges of the laterally-extending wing. The dimensions of the column member and the flying attitude of the glide test head are selected to make the lowermost surface of the column member the closest contact point of the entire test head during test operation, and to contribute minimal effect on the overall hydrodynamic operation of the glide test head. In a related aspect of the invention, it is envisioned that the test system in which the inventive glide test head is implemented will spin the disc under test at a greater than normal speed, thus increasing the throughput of the test system.

Abstract: A disc storage system includes a rotating disc and a transducer. The transducer is carried on a slider which is supported by an armature. The armature is used to move the slider radially across the disc surface whereby information may be read from or written to the disc surface of the transducer. The slider includes an air bearing surface which faces the disc surface. As the disc rotates, the air bearing surface causes the slider to “fly” over the disc surface. Pads are provided on the air bearing surface to improve operational characteristics of the system.

Abstract: A disc drive, includes a base, a disc stack rotatably attached to the base, and an actuator assembly movably attached to the base. The actuator assembly also includes a bearing housing, head mounting arms, head suspensions attached to the head mounting arms and a head assembly attached to the head suspension. The disc drive also includes a hub having a cylindrical body. The hub includes a disc mounting flange on one end of the hub. A disc has an opening therein sufficient to allow the hub to fit within the opening of the disc. The disc has two substantially flat data surfaces. The disc also includes a disc clamping portion located near the opening in the disc. A clamp is used to attach the disc to the hub. At least one disc is placed onto the hub and onto the mounting flange of the hub. The clamp is then used to clamp the disc to the hub. The disc clamping portion includes features for accommodating differences in flatness between the disc surfaces, the mounting flange of the hub and the clamp.

Abstract: A glide testing apparatus includes a motor assembly, a sensor element, a positioning assembly, and detection circuitry. The motor assembly rotates a magnetic disk about an axis. The sensor element produces a detection signal in response to disk surface characteristics. The positioning assembly positions the sensor element at selected radii from the axis of disk rotation, and the detection circuitry receives a signal from the sensor element to detect movement of the sensor element between a first zone on the disk and a second zone on the disk. Methods of distinguishing between two adjacent zones on a magnetic disk include rotating a magnetic disk about an axis and positioning a sensor element at selected radii from the axis of rotation.

Abstract: A glide head that can be coupled to a mounting base via a load arm includes a gimbal. A slider is coupled to the gimbal and includes an air bearing surface having a downward protrusion. The distance between the protrusion and a disc under test is substantially insensitive to changes in a height measured from a bottom of the mounting base to an upper surface of the disc. Furthermore, the protrusion can have a distal end extending downward such that a distance from the distal end to the disc under test is less than a distance from every other surface of the slider to the disc during operation of the glide head. The glide head can have a fly height that is substantially constant. Therefore, the glide head can provide more accurate and more uniform detection of outwardly projecting defects on the surface of the disc.

Abstract: A glide head apparatus for testing surface characteristics of a disc includes a gimbal, a slider and an actuator including a piezoelectric material disposed between the gimbal and the slider. A voltage applied across the piezoelectric material is controllable to cause the piezoelectric material to expand or contract depending on the applied voltage so as to vary the fly height between the slider and a disc under test. The fly height can be varied without substantially varying the linear velocity of the disc under test. Methods of testing surface characteristics of a disc using the glide head apparatus also are disclosed.