Abstract: In order to operate a communication terminal for packet-oriented data transmission, at least one piece of status information is stored, for a communication terminal, in a memory unit associated with the communication terminal. Said status information is provided with a digital signature that is calculated from the status information by means of a private key for an asymmetrical encoding method associated with a first control unit associated with the communication terminal, for the resolution and/or conversion of network addresses. If the first control unit fails, a request is transmitted comprising the status information and the digital signature to associate the communication terminal with at least one second control unit, and the digital signature is checked. In the event of a positive check result, the communication terminal is associated with the second control unit.

Abstract: Even when encoded (compressed) image data appended with an error-detecting code is encrypted, the apparatus which receives and reproduces that image data can execute a normal process without any insignificant re-send request and the like. To this end, encoded image data is input, and first error-detecting encoding information contained in its header is checked to determine whether or not an error-detecting code is appended. If it is determined that the error-detecting code is appended, the first error-detecting encoding information is changed to indicate the absence of an error-detecting code, and is saved as second error-detecting encoding information. Then, the encoded image data is encrypted.

Abstract: A method (300) of performing photon detector autocalibration in quantum key distribution (QKD) system (200) is disclosed. The method (300) includes a first act (302) of performing a detector gate scan to establish the optimum arrival time of a detector gate pulse (S3) that corresponds with a maximum number of photon counts (NMAX) from a single-photon detector (216) in the QKD system (200). Once the optimal detector gate pulse arrival time is determined, then in an act (306), the detector gate scan is terminated and in an act (308) a detector gate dither process is initiated. The detector gate dither act (308) involves varying the arrival time (T) of the detector gate pulse (S3) around the optimal value of the arrival time established during the detector gate scan process. The detector gate dither provides minor adjustments to the arrival time to ensure that the detector (216) produces maximum number of photon counts (NMAX).

Abstract: A magnetic disk apparatus capable of reducing deformation of a magnetic disk is disclosed. The magnetic disk apparatus comprises a magnetic disk on which data is recorded while the disk is driven, a hub around which the magnetic disk is supported from an under side of the magnetic disk, and a clamp in contact with the other side of the magnetic disk and fixing the magnetic disk. An O-ring is interposed between a flange formed at an outer circumference of the hub and the magnetic disk, and a spacer is interposed between the magnetic disk and the O-ring. Thus an upper surface of the hub is in contact with an under surface of the clamp and defines a vertical position of the magnetic disk.

Abstract: A flexible printed circuit board using a lead-free solder is to be fixed within a disk enclosure while ensuring a high rigidity. In one embodiment, a rotating disk storage device comprises a flexible printed circuit board (FPC), wherein there is formed a wiring pattern including a signal line for the transmission of a signal of data read by a head in an actuator head suspension assembly (AHSA) and wherein one side end portion is fixed to a base and an opposite side end portion is fixed to the AHSA. A first metallic plate and a second metallic plate are both fixed to one side end portion of the FPC. A connector is disposed in an area where the first metallic plate in the FPC is provided, and connected to the wiring pattern. A shock sensor is disposed in an area where the second metallic plate in the FPC is provided, and connected to the wiring pattern.

Abstract: An integrated optical head is provided. In the integrated optical head, a light source emits light. A waveguide guides the light. An input coupler is located at one edge of the waveguide, and couples light emitted from the light source and transmits the coupled light to the waveguide. An output coupler is located at another edge of the waveguide, and couples light emitted from the waveguide and focuses the coupled light on an optical disc. A light path changing unit is installed on the waveguide, and changes the light path of light that has been reflected by the optical disc and then passed through the output coupler. An optical detector receives the light passed through the light path changing unit and converts the received light into an electrical signal in order to detect information from the optical disc. Accordingly, an input coupling efficiency and an output coupling efficiency are improved, such that light loss is reduced.

Abstract: Disclosed is a magnetic circuit operable in multiple axes in an optical pick-up actuator. The optical pick-up actuator includes: a lens holder for receiving and moving an object lens in a predetermined direction; a magnetic circuit having; a plurality of coils series and parallel connected and attached to both sides of the lens holder; a yoke and a magnet faced with the coils, for generating and inducing different polarities in perpendicular directions. With such construction, the actuator moves the lens holder to tracking, focusing, tilting directions under control of a direction and intensity of a current by the magnetic circuit.

Abstract: A read channel includes a signal receiver that receives a read back signal and a signal detector to detect symbols in the read back signal. The signal detector includes a first detector that generates raw decisions as a function of the read back signal, a post processor that identifies possible defects in the raw decisions, a selector that independently receives the raw decisions and a list of the possible defects from the first detector and the post processor, respectively, and a decoder that generates final decisions based on the raw decisions and the possible defects identified by the post processor. The decoder performs at least one of Reed-Solomon decoding, Bose Chaudhuri Hocquerghen (BCH) decoding and Hamming Decoding.

Abstract: A magnetic tape includes plural diagonal tracks, each storing a preamble sequence close to user data such that a transducer for reading the track reads the preamble sequence immediately before reading the user data. The preamble sequence is such that when the track is read by the transducer the preamble sequence has a power sequence with a power spectrum substantially equivalent to the power spectrum of the user data. An AGC circuit responds to the transducer.

Abstract: A high-density optical disc such as a high density-digital versatile disc (HD-DVD) or Blu-ray disc, and a method for reproducing or recording data of the high-density optical disc. The high-density optical disc includes a lead-in area, a data area and a lead-out area. The lead-in area has control information. A minimum mark or space length of the control information recorded in the lead-in area is longer than that of data recorded in the data area. The control information of the lead-in area is copied to the lead-out area. On the basis of the data reproduction or recording method, an optical disc device can correctly read and confirm the control information from the high-density optical disc, minimize the interference between a mark and space in high-density recording data, reduce the effects of scratches or dust on the disc, and efficiently prevent an erroneous data reproduction or recording operation.

Abstract: A tape recording system is provided for coupling the angular velocities of a pair of roller guides disposed one on either side of a head assembly. In one embodiment, the roller guides each comprise cylindrical first and second surfaces wherein the first surfaces guide a tape over the head assembly. An idler bearing comprising a cylindrical ring having an inside diameter surface engages in rolling contact the second surfaces of the pair of roller guides, thereby coupling the angular velocities of the pair of roller guides. In another embodiment, an idler bearing comprises a roller having an outside diameter surface that engages the surfaces of a pair of roller guides on each side of the head to couple the angular velocities of the pair of roller guides.

Abstract: An apparatus for detecting abnormal states which prevents damage to a laser diode or data recorded on a disc and swiftly correcting the abnormal state. An overflow/underflow detector detects whether overflow or underflow of the laser diode occurs, by comparing a laser diode output power control value, which is output from the laser diode output power control circuit, with an overflow setting value and an underflow setting value. A mode switch switches an operation mode of the laser diode output power control circuit from a recording mode to a reproducing mode, in response to the detection result of the overflow/underflow detector.

Abstract: Embodiments of the invention avoid an off-track write when an impact is applied. A hard disk drive according to one embodiment of the present invention comprises a magnetic disk; an actuator for moving a head element section over the magnetic disk; and an HDC/MPU for prohibiting the head element section from writing onto the magnetic disk for a short period when a detected impact is found to be greater than a low reference level and not greater than a high reference level, and prohibiting the head element section from writing onto the magnetic disk for a period longer than the short period when the detected impact is found to be greater than the high reference level.

Abstract: A method and an apparatus to write and inspect servo information on a disc drive and minimize an effect on servo information written in adjacent tracks caused by a gap erase field, and write servo information on the disc drive and perform servo information inspection and defect processing. The method includes sequentially writing servo information toward a track having skew ‘0’ at from outer surface in an outer region of the disc, and sequentially writing the servo information toward the track having skew ‘0’ from an inner surface in an inner region, and after writing of the servo information is completed, inspecting the servo information written in a track at a predetermined distance from the track having skew ‘0’, and determining whether the servo information is correctly written.

Abstract: A method of servo writing a disk for use in a disk drive is disclosed by writing discontinuous spiral tracks on the disk to protect against overheating the head and/or preamp circuitry. A write clock is synchronized to the rotation of the disk, and a plurality of discontinuous spiral tracks are written on the disk. Each discontinuous spiral track is written at a predetermined circular location determined from the write clock, and each discontinuous spiral track comprises a plurality of segments separated by gaps. Each segment comprises a high frequency signal interrupted at a predetermined interval by a sync mark.

Abstract: Disclosed is a deck for a magnetic recording/reproducing apparatus. The deck has a chassis in which a plurality of structures constituting a mechanical mechanism for loading a tape and recording or reproducing information; and a switch/sensor circuit board in which a plurality of switches and sensors constituting an electronic mechanism for detecting an operation of the deck and a state of the structures. The switch/sensor circuit board is formed of a PCB and assembled to a lower surface of the chassis.

Abstract: An actuator includes a focusing-substrate having a focusing coil pattern for generating focusing driving force, the focusing-substrate being provided with a land part and a hole through which laser beams pass, tracking coils for generating tracking driving force, the tracking coils being wound around opposite sides of the focusing substrate in parallel with the a wire direction, magnets for providing magnetic force to the focusing coil pattern and the tracking coils, and a yoke plate provided with a pair of first yokes for fixing the magnets.

Abstract: The present invention relates to a magnetic disk device and provides a magnetic disk device in which data recording areas are separately set based on the inner recording boundary or outer recording boundary of the head measured for each magnetic disk device. When the recording linear (angular) density that has to be attained to ensure a prescribed capacity cannot be attained by the head, the recording linear (angular) density that has to be attained by the head is reduced and the prescribed capacity is realized by expanding the data recording area. A method using a counter-electromotive force generated when the head is moved toward a stopper or ramp load or a method by which the measurements are conducted based on the head position information from the servo signal can be used for measuring the positions of the inner recording boundary and outer recording boundary of the head.

Abstract: An optical pick-up device comprising at least one micromirror array lens. The micromirror array lens enables focusing, tracking, and/or tilt compensation in the optical pick-up device without macroscopic motions. The micromirror array lens provides the device with a simple structure, which can reduce the size, weight, and cost of the recording/reproducing system. The device is also durable for vibration. Optical pick-up devices using an array of micromirror array lenses can increase the recording/reading speed without macroscopic motions. The recording/reading speed can be increased by adding more micromirror array lenses to the lens array. The present invention can also be used to record/read information on/from a multi-layered optical disc.

Abstract: An object of the present invention is to attain stable tracking servo performance by suppressing an offset caused by a shift of an object lens or a tilt of a disk, despite the one-beam method which does not cause reduction in light quantity of the main beam. A diffraction grating is provided between a hologram and a light receiving section, and a diffraction efficiency of the diffraction grating is varied in a grating longitudinal direction. For example, if an incident light beam on the diffraction grating is shifted in the grating longitudinal direction, the quantity of received light in each light receiving section varies to cause offset. By performing tracking servo so as to cancel the change, it is possible to correct the offset, thereby attaining stable tracking servo performance.