Abstract: A method is provided for writing a servo-pattern on a storage medium. According to the method, first timing marks are written at a first radial position of the storage medium, and the head is moved to a second radial position. Time intervals between selected pairs of the first timing marks are measured, and other timing marks are written at the second radial position of the storage medium. The measuring step is performed after the moving step. In one preferred method, the steps of moving, measuring, and writing other timing marks are repeated until the servo-pattern is written on an entire surface of the storage medium. A method is also provided for generating an initial aligned pattern of timing marks for self-servo-writing on a storage medium.

Abstract: A method and apparatus for mapping the character and location of small surface variations on a planar surface. Energy in the form of pulses is supplied to an object in close proximity to the planar surface to thereby raise the temperature of the object and at part of the surface. A change in temperature of the object is detected when it is in proximity to the variation to define the location and character of the variation. By supplying the energy in the form of pulses, the size of the thermal signature produced in the planar surface is limited wherein a more accurate and more sensitive mapping method and apparatus are provided. The energy supply may be thermal energy or optical energy but preferably is electrical energy which heats a resistive element. Preferably, the object is a magnetoresistive head of a disk drive assembly and the surface may be that of a magnetic recording material. The change in temperature is detected by monitoring the resistance of the magnetoresistive coil of the head.

Abstract: A method for writing tracks on a rotating disk media data storage device comprising the steps of: receiving a set of component parameters; and adjusting track pitch for each of the tracks to be written in each disk according to the component parameters. According to another embodiment a disk drive includes at least one disk comprising a two or more of tracks in which the track pitch between each pair of adjacent tracks is set based on component parameters such as the recording head widths. According to another embodiment a servowriter is adapted to perform the method discussed above.

Abstract: A disk drive which incorporates separate actuators for each recording head so as to only place required recording heads over the recording media of multiple surface hard disk drives. The reduction in recording heads that are placed over the recording media reduces drag on the rotating disk holding the recording media and thereby reduces the power consumption. Reducing the number of recording heads over the recording media also reduces damage to the recording media surfaces in the event of a physical shock to the drive since inactive transducer heads are not in a position to damage the recording media.

Abstract: An electronic event recorder for attachment to a vehicle is provided which can broadcast encrypted signature and data, thereby leaving behind an electronic version of a “fingerprint” in the event of an accident or traffic violation. The fingerprint, captured by an external data acquisition system or another vehicle so equipped, provides a history of events related to the vehicle. The event recorder is preferably integrated on a smart card and housed in a tamper proof casing. In a first mode of operation, monitoring stations along the roadways periodically send an interrogation signal, such as when radar detects that the vehicle is speeding. Upon receiving the interrogation signal the smart card transmits the vehicle's signature information to the monitoring station where it is time and date stamped along with the speed of the vehicle.

Abstract: The present invention provides methods and apparatus to detect and reliably record the physical history of a product including effects due to one or more of the following: 1) product use 2) handling 3) tampering and 4) environment of the product (as changes in the environment, such as excessive temperatures, humidity, or shocks, can result in degradation to a product). The apparatus includes a “smart card”, or, more generally, “smart token”, in combination with one or more sensors which record the external influences on the product and/or the environment and records those changes in an encrypted form. This information can then be verified by any individual who is equipped with a (possibly public) decryption key, but capability to modify this information, depending on the application, is restricted to those with access to the encrypting key.

Abstract: A method and apparatus for mapping the character and location of small surface variations on a planar surface. Energy in the form of pulses is supplied to an object in close proximity to the planar surface to thereby raise the temperature of the object and at part of the surface. A change in temperature of the object is detected when it is in proximity to the variation to define the location and character of the variation. By supplying the energy in the form of pulses, the size of the thermal signature produced in the planar surface is limited wherein a more accurate and more sensitive mapping method and apparatus are provided. The energy supply may be thermal energy or optical energy but preferably is electrical energy which heats a resistive element. Preferably, the object is a magnetoresistive head of a disk drive assembly and the surface may be that of a magnetic recording material. The change in temperature is detected by monitoring the resistance of the magnetoresistive coil of the head.

Abstract: The present invention provides methods and apparatus to detect and reliably record the physical history of a product including effects due to one or more of the following: 1) product use 2) handling 3) tampering and 4) environment of the product (as changes in the environment, such as excessive temperatures, humidity, or shocks, can result in degradation to a product). The apparatus includes a “smart card”, or, more generally, “smart token”, in combination with one or more sensors which record the external influences on the product and/or the environment and records those changes in an encrypted form. This information can then be verified by any individual who is equipped with a (possibly public) decryption key, but capability to modify this information, depending on the application, is restricted to those with access to the encrypting key.

Abstract: A method for writing timing marks on a rotatable storage medium, such as on a disk in a disk drive, includes the steps of: 1) during a rotation of the disk, detecting the passage of at least a portion of a first timing mark located at a first radius of the disk, and 2) writing a second timing mark at a second radius of the disk, the location of the second timing mark being based at least in part on a stored calculation of a delay from the time of passage of the first timing mark during a rotation of the rotatable storage medium. The location of the second timing mark is calculated based on alternative time intervals between detected timing marks and on various functions of the time intervals.

Abstract: An electronic event recorder for attachment to a vehicle is provided which can broadcast encrypted signature and data, thereby leaving behind an electronic version of a “fingerprint” in the event of an accident or traffic violation. The fingerprint, captured by an external data acquisition system or another vehicle so equipped, provides a history of events related to the vehicle. The event recorder is preferably integrated on a smart card and housed in a tamper proof casing. In a first mode of operation, monitoring stations along the roadways periodically send an interrogation signal, such as when radar detects that the vehicle is speeding. Upon receiving the interrogation signal the smart card transmits the vehicle's signature information to the monitoring station where it is time and date stamped along with the speed of the vehicle.

Abstract: An electronic event recorder for attachment to a vehicle is provided which can broadcast encrypted signature and data, thereby leaving behind an electronic version of a “fingerprint” in the event of an accident or traffic violation. The fingerprint, captured by an external data acquisition system or another vehicle so equipped, provides a history of events related to the vehicle. The event recorder is preferably integrated on a smart card and housed in a tamper proof casing. In a first mode of operation, monitoring stations along the roadways periodically send an interrogation signal, such as when radar detects that the vehicle is speeding. Upon receiving the interrogation signal the smart card transmits the vehicle's signature information to the monitoring station where it is time and date stamped along with the speed of the vehicle.

Abstract: Methods and systems for self-servowriting a data storage medium are disclosed, including servoing to propagation bursts of a propagation pattern located in tracks other than an immediately preceding track. Reference levels used to position a recording head are accordingly kept in a usable dynamic range necessary to keep servo track spacing constant across the medium. The methods and systems are disclosed in connection with a rotary actuator having spaced read and write heads. Similar methods are disclosed for writing trigger or timing bursts of the propagation pattern.

Abstract: A technique for writing a servo-pattern on a storage medium located in a recording device having an internal recording head. A timing pattern is generated on the storage medium with the internal recording head and a radial positioning value is determined in order to radially position the internal recording head. The servo-pattern is written using the internal recording head at locations determined by the timing pattern and the radial positioning value.

Abstract: During a write revolution of a storage medium, a transition is written on the storage medium while servoing on another transition previously recorded on the storage medium. During that write revolution, a position error signal corresponding to the position error of the transducer relative to the previously recorded transition is determined. That position error signal is then stored, during the write revolution, to be used in computing a reference track value associated with the transition being written to correct for the position error. Additionally, a product servo-pattern is written, which includes an embodying of the position error therein.

Abstract: A technique for writing a servo-pattern on a storage medium located in a recording device having an internal recording head. A timing pattern is generated on the storage medium with the internal recording head and a radial positioning value is determined in order to radially position the internal recording head. The servo-pattern is written using the internal recording head at locations determined by the timing pattern and the radial positioning value.

Abstract: A technique for writing a servo-pattern on a storage medium located in a recording device having an internal recording head. A timing pattern is generated on the storage medium with the internal recording head and a radial positioning value is determined in order to radially position the internal recording head. The servo-pattern is written using the internal recording head at locations determined by the timing pattern and the radial positioning value.

Abstract: A sealed direct access storage device wherein a head is positioned for interaction with a storage medium in which the relative humidity is controlled by placing a predetermined amount of desiccant and a predetermined amount of water in the sealed volume of the device. At any given steady state temperature within a predetermined operating range the water vapor within the free space within the device and the water contained in the desiccant are in equilibrium and the relative humidity is controlled within acceptable limits.

Abstract: A laser (10) provides an output beam to an interferometer (12). A portion of the output beam is directed by a beamsplitter to a receiver (18) as a reference beam while the remaining portion of the output beam passes through the beamsplitter and impinges on a plane mirror reflective surface (14a) mounted upon or integrally formed with or upon a surface of a body of interest, such as rotary actuator or arm (14). The arm has a fixed center of rotation O and rotates through an angular range indicated by theta-max. Phi is the angle of incidence of the laser beam with the arm in its original position when theta equals zero. .vertline.OC.vertline. and .vertline.CD.vertline. are distances which locate the intersection point between the arm and the laser beam relative to the center of rotation O when theta equals zero. A corner cube (16) is located at a convergence plane and returns all reflected beams back to the plane mirror and hence to the receiver via the interferometer.

Abstract: A method and apparatus for measuring dynamic head and track misregistration in, for example, a magnetic disk file. A reference signal waveform is recorded onto a track on a recording medium. The track has a center line and an off-center line parallel to the center line. The recorded reference signal waveform is read a plurality of times with the transducer centered approximately above the off-center line of the track to produce a plurality of off-track playback signal waveforms. A track misregistration signal waveform is produced by computing the difference between one off-track playback signal waveform and the average off-track playback signal waveform.

Abstract: A high speed, small diameter disk storage system having a plurality of disk drive devices utilizing disks with a nominal 65 mm diameter rotated at a speed of approximately 10,000 RPM which can be optimally arranged in a four drive system to match the space geometry of the traditional half-high flexible disk drive used in a personal computer.