Abstract: A method and system for managing a plurality of defects that may cause an error during a write operation in a write-once data storage disk is provided. A host system sends a write command to a disk drive that contains the storage disk. The process detects any errors that may occur during the write operation. When an error is detected, a “skip list” containing the addresses of physical sectors on the disk that are to be skipped during a read operation is updated, the write operation is suspended, and the process attempts to rewrite the data in another sector. If the rewrite is performed successfully, the write operation continues. Otherwise, the write operation is terminated and the host device is notified. While the disk drive is operative, the skip list is preferably maintained in a buffer memory, but periodically the entries in the skip list are copied to the disk for permanent storage. Before a read operation begins, the skip list is copied from the disk to the memory.

Abstract: A system and method is provided for authenticating a device. A method includes receiving a certificate from the device, the certificate including a plurality of fields, including a field holding a digital signature from a certifying authority, verifying the digital signatures in the certificate, the verifying including at least one of verifying the certifying authority digital signature using the certifying authority public key; and verifying a device digital signature using a device public key, and receiving validation data from a source, the validation data identifying one or more data in the certificate as valid or invalid according to predetermined criteria, and if the digital signatures are verified and validated, transmitting a session key to the device to establish a secure communication channel.

Abstract: An optical medium including a substrate and information content portions is provided. The optical medium is preferably a first-surface medium in which a read light beam during a read operation impinges first on the information content portions of the medium before it impinges on the substrate. The information content portions can include both read-only and writeable areas. The information content portions containing both read- only and writeable areas can be made from the same material or composition. The optical medium diameter is no greater than about 40 mm. The thickness of the optical medium is no greater than about 0.6 mm. When joining a hub assembly to the medium, a portion of the medium, such as a track, is utilized for alignment purposes. The ratio of the total height of the hub assembly to the thickness of the optical storage medium is at least about 1.5. The hub assembly can include a magnetic coupling for use in connecting the optical medium to an optical drive spindle.

Abstract: A system and method is provided for detecting unauthorized actions with respect to encrypted data on a media disk, the media disk including a first portion for prerecorded content and a second portion for written content. The method includes reading an identifier on the media disk, wherein the identifier includes one or more sections located in one of the first portion for pre-recorded content, the second portion for written content, and both the first portion for pre-recorded content and the second portion for written content, determining whether the identifier includes a section located in the second portion written content, comparing the identifier with one or more predetermined types of identifiers for which a section is located in the second portion for written content, and if the identifier is of a type that is one of the one or more predetermined types of identifiers, detecting an unauthorized action.

Abstract: An optical medium uses a single structure or format (such as identical materials, layers and the like) for both a region for holding mastered data and a writeable area. In one aspect, a writeable region of a medium with mastered content is used in connection with paying, collecting or accounting for usage or royalties for proprietary intellectual property embodied in or associated with the content. In one embodiment, the (preferably write-once) writeable area can be used for storing later-written information such as annotations, highlighting, reordering, remixing, modifications, supplements, collections, additions, bookmarks, cross references, hypertext or hyperlinks and the like. Preferably, annotations and similar materials can be associated, by the user, with particular portions or content of the mastered data.

Abstract: Micro lenses are fabricated using processes which operate on multiple lenses at a time. In one embodiment, wafer-scale processing includes employing photolithography for defining gray-scale masks which permit relatively smooth or continuous curvatures of lens surfaces to be formed by, e.g., reactive ion etching. Processes and materials are used which achieve desired etching at a sufficiently rapid rate such as etching to a depth of about 200 micrometers in less than about 10 hours. Wafer-scale molding processes can also be used. Diffractive features can be formed on or adjacent lens surfaces to provide functions such as dispersion correction. Also, sub-wavelength scale features may be etched to provide quarter-wave plate functionality, birefringence, anti-reflective functions and the like. Structures such as mounting rings and/or crash stops can be formed integrally with the lens body, eliminating the need to glue or otherwise couple separate components.

Abstract: The present invention is related to a method and apparatus for limiting movement of an actuator assembly in a data storage/retrieval system. In one embodiment of the apparatus, a base is provided on which first and second devices are mounted. The first device is rotatably mounted to the base and reads or writes data to a data storage disk. The second device operates between first and second states. In the first state, the first device is capable of movement with respect to the base. In the second state, the second device operates to inhibit movement of the first device with respect to the base. The second device may operate in the first state when the first device is reading or writing data to the data storage disk, and the second device may operate in the second state when the first device is not reading or writing data to the data storage disk. In one embodiment, second device is rotatably mounted to the base between first and second positions.

Abstract: US vi A calibration of input signal offsets for stray light in an optical disk drive is presented. The input signal offsets can be determined by setting a laser power level, receiving digitized input signals, and setting the input signal offsets so that the digitized input signals are zero. The laser power level can be a read power or a write power. In some embodiments, input signal offsets for both read power and write power are determined and stored.

Abstract: A calibration of a loop gain in a digital servo system is presented. The loop gain can be calibrated measuring the response in a control signal generated by the digital servo system when the control signal is replaced by a sum of the control signal and a sinusoidal disturbance. The loop gain can be set to provide a desired gain, for example unity, between the control signal and the sinusoidal disturbance at a cross-over frequency.

Abstract: A notch filter that filters a focus error signal during a multi-track seek operation is presented. The notch filter has a center frequency that relates to the seek reference velocity of a multi-rack seek algorithm. During the multi-track seek operation, a focus control signal is calculated from the filtered focus error signal from the notch filter.

Abstract: A sample integrity test is disclosed. The sample integrity test receives an error signal and a defect signal. If the defect signal indicates the presence of a defect, a low-pass filtered error signal is substituted for the error signal. The low-pass filtered error signal is the error signal filtered with a low-pass filter. The error signal can be derived from optical signals from an optical pick-up unit. A control signal generated from the output signal from the sample integrity test controls the position of the optical pick-up unit. The defect signal can also be derived from the optical signals.

Abstract: A system for controlling focus in an optical disc drive for optical media with a premastered area that cannot be overwritten and a user-writeable area that can be overwritten includes instructions for turning focus on and off; and for acquiring focus on the optical media in response to a command to acquire focus. The actuator arm is moved according to a sinusoidal ramp function to prevent exciting resonances in the actuator arm. The amount of push-away force used while moving the actuator arm can be adjusted to avoid overshoot. The integrity of a focus error signal is determined and an attempt to re-acquire focus is made if the focus error signal indicates a bad focus status.

Abstract: A servo system with a multi-track seek algorithm with an accelerated servo function for regaining a closed tracking loop is presented. Upon completion of a multi-track seek operation, a gain of a tracking servo system is increased for a predetermined number of cycles. In some embodiments, the increased gain leads to a more aggressive track closing operation.

Abstract: A direction sensor in a tracking and focus servo system of an optical disk drive is presented. The direction sensor calculates a direction sum signal and a tracking error signal from side elements of detectors in an optical pick-up unit of the optical disk drive. A first direction can be indicates when the signs of a high-pass filtered sum signal and a high pass filtered tracking error signal are opposite and a second direction opposite the first direction if the signs are the same.

Abstract: A servo system with a multi-track seek algorithm with an track zero crossing period integrity test is presented. Zero crossing periods for subsequent cycles can be determined from a tracking error signal. If the zero crossing period for a first cycle differs substantially from the zero crossing period for a second cycle, then an error can be indicated. In some embodiments, the first cycle and the second cycle are subsequent cycles. In some embodiments, the zero crossing period in the second cycle can be between half and twice the zero crossing period in the first cycle. In some embodiments, other ranges are utilized. For example, in some embodiments the zero crossing period in the second cycle can be between one quarter and four times the zero crossing period in the first cycle.

Abstract: A digital servo system with a biased feed-forward control is disclosed. The biased feed-forward control determines the low frequency component of a control signal from the digital servo system. The low frequency component can then be added to a future control signal to form an adjusted control signal. In some embodiments, the low frequency component is then removed from the future control signals. In some embodiments, a bias signal is incremented or decremented in response to the low frequency component, the bias signal being added to future control signals.

Abstract: A system and method for handling events issued as a result of error conditions in the operation of an optical disc drive include suspending processing of commanded operations in the disc drive while attempting to recover from the error condition. The recovery attempt can include increasing levels of recovery effort, such as dynamically recalibrating various components in the disc drive. The system can also determine whether a previous notice was received for the same error condition. If so, the system can determine whether excessive recovery attempts have been initiated based criteria such as the time between the notices, and/or the number of notices, for the same error condition. The recovery attempts are aborted when they become excessive. If the recovery attempt is successful, the interrupted operation is resumed at the point where the processing was suspended, such as during a write or read command.

Abstract: A calibration method for an optical disk drive is presented. The operating parameters of an optical disk drive are initially calibrated when the disk drive is produced or during a repair step. The disk drive is then field calibrated during normal operation. Operating parameters can be field calibrated during power up. Further, operating parameters can be field calibrated when a new optical media is inserted into the optical disk drive. Additionally, operating parameters can be field calibrated during error recovery.

Abstract: A head load algorithm for an optical disk drive is presented. On startup, the optical media can be spun up. Then an optical pick-up unit can be positioned at an extreme position, for example at the inner diameter, and focus can be closed. The optical pick-up unit then can be incrementally moved away from the extreme position while the tracking error signal is monitored to locate an area of the optical media with tracks. Once the area is located, a tracking servo system can close on one of the tracks.

Abstract: A calibration for a tracking error signal offset in a tracking servo system of an optical disk drive is presented. In some embodiments, the tracking error signal offset is adjusted for best servo function by, for example, adjusting the center of a tracking error signal when the tracking servo system is open to zero. In some embodiments, the tracking error signal offset is adjusted for best read function by, for example, adjusting the tracking error signal offset until the data jitter is minimized. Data jitter can be determined by reading data from the optical media and measuring the data error rate.