Abstract: Apparatus and method for generating an analog waveform, such as a deflection signal used to deflect a write beam during the writing of data to a rotatable medium having a variable track pitch (TP). In accordance with various embodiments, a first digital to analog converter (DAC) is configured to output a deflection signal having an analog voltage level corresponding to a magnitude of a first multi-bit digital input value applied to the first DAC. A second DAC is configured to supply a rail voltage to the first DAC having an analog voltage level corresponding to a magnitude of a second multi-bit digital input value applied to the second DAC. The deflection signal is used to deflect a write beam supplied by a write beam generator.

Abstract: Method and apparatus for providing a hidden signature to a recording medium, such as an optical disc (102). The hidden signature is generated in relation to the selected sequencing of data blocks (132, 134, 136, 138, 140, 142). A plurality of) mutually exclusive, valid possible states are identified for each of the data blocks (202), each state conforming to requirements set forth by a published standards document to which the optical disc conforms. A different logical value is assigned to each of the possible states, and the hidden signature is selected as a multi-value logical word comprising a sequence of the logical values (204). The hidden signature is thereafter written to the optical disc by writing a set of corresponding data blocks at selected locations on the optical disc having states corresponding to the multi-value logical word (206). The hidden signature thereafter facilitates copy protection or forensic tracking efforts (208).

Abstract: Method and apparatus for formatting a data storage medium, such as a magnetic or optical disc. In accordance with various embodiments, a data storage medium is rotated while a write beam is used to write data to the rotating medium. The data are written in the form of a plurality of concentric data tracks. A deflection angle of the write beam is continuously adjusted in an axial direction along each track. In some embodiments, the axial deflection of the write beam imparts a desired angular offset between a beginning point of a first track and a beginning point of an immediately adjacent second track. This allows a first translation geometry, such as a linear translation path of a linear actuator, to emulate a different second translation geometry, such as a rotary translation path of a rotary actuator.

Abstract: Apparatus characterized as a multi-session data storage medium such as an optical disc, and method for formatting the same. In accordance with various embodiments, a first session is recorded onto the medium with a first set of user data. A second session is subsequently recorded onto the medium with a second set of user data. The second session contactingly abuts the first session without the use of an intervening linking area therebetween. This enhances the data storage capacity of the medium irrespective of the total number of sessions applied thereto. In some embodiments, the first session is described by a first file system and the second session is described by a different, second file system independent of the first file system. The respective file systems may be accessed by different readback systems, such a personal computer (PC) and a gaming system.

Abstract: Method and apparatus for providing a storage medium with variable track widths. In accordance with various embodiments, a data storage medium is rotated by a motor. A write transducer is used to write concentric data tracks to the storage medium during said rotation. The tracks are provided with variable track widths established by selectively changing a rotational velocity of the medium. The variable track widths can be gradual and/or abrupt, depending on the requirements of a given application. Gradual variations in track width can be used by a linear actuator with a linear translation path to emulate tracks written along a pivot translation path of a rotary actuator. Abrupt variations in track width can be used to provide different zones of tracks having different specified track widths. The tracks may be written using an electron beam recorder (EBR) with a constant write beam power level.

Abstract: An optical disc (102) and method for forming the same. The optical disc preferably includes a first substrate (150) comprising a pre-recorded, first data storage layer (152) and a second substrate (156) comprising a recordable, second data storage layer (158). The second substrate is affixed to the first substrate such that a data transducing beam (161) passes through a common exterior boundary surface (162) of the disc to access the respective first and second layers. Preferably, the pre-recorded layer comprises a sequence of pits and lands (218). Addresses of blocks in the respective layers preferably successively increment (220) so that a readback system (100) interprets the respective layers as a common recording layer within the disc. One of the layers can store disc authentication data zone, a patch which updates a version of user data stored in the remaining layer, etc. A content supplier can supply specially configured substrates with pre-recorded control data to control disc manufacture.

Abstract: Method and apparatus for tracking layers in a multi-layer optical disc. The disc includes a first layer which stores a first set of user data and a table of contents (TOC) for the disc. A second layer stores a second set of user data and an identifier tag which identifies the second layer as corresponding to the first layer. The identifier tag can comprise a portion of, or a complete copy of the TOC, or can comprise a reference value which, among other things, identifies a revision level of the second layer. Preferably, the first layer is also provided with a reference value. In this way, a database or other mechanism can be used to track the history of the various layers of the disc. Stampers form the respective layers and the ID tags further serve to ensure correspondence thereof in the formation of the disc.

Abstract: Method and apparatus for compensating for differences in translation path geometries of transducers used to access a data storage medium. A compensation profile is generated in relation to radial error between a first translation path geometry of a first transducer and a different, second translation path geometry of a second transducer. A control circuit directs the first transducer to write data to a rotatable data storage medium in relation to the compensation profile to emulate the second translation path geometry. In some embodiments, the control circuit comprises a data signal clock generator, a motor rotation clock generator, and a transducer radial translation clock generator. A nearest pulse detector identifies a closest clock signal pulse to a once-per-revolution (OPR) rotational reference, and the control circuit adjusts a frequency of the associated clock signal coincident with said closest pulse.

Abstract: An apparatus and method for determining a separation distance between radial locations on a data storage medium, such as an optical disc. A first number of channel bits are detected at a first radial location of the medium, and a second number of channel bits are detected at a second radial location. The radial separation distance therebetween is determined in relation to the respective first and second numbers. Preferably, the first radial location is a first track on the medium, and the second radial location is a second track on the medium. Preferably, a motor rotates the medium, a data transducer transduces readback signals from the first and second locations, and a processor determines the respective numbers of bits from the readback signals. The radial separation distance is preferably used to authenticate the medium.

Abstract: A data storage medium (230, 400) and associated method (500, 520), apparatus (250, 430) and application routine (110, 524) for authenticating the medium as an authentic copy. The medium (such as a prerecorded or recordable optical disc) is formatted so that a predefined relationship is established (502) between physical locations of at least first and second addressable data sectors (220) prior to recording of data to the sectors (506). The predetermined relationship will be present in an authorized copy of the medium (330) but not in an unauthorized duplicate (332), allowing an application routine to grant or deny access (532, 534) to remaining portions of the medium based on the presence or absence of the detected relationship. The predetermined relationship is further used to embed a forensic data payload to serve as a digital fingerprint on the medium.

Abstract: Method and apparatus for authenticating a data storage medium (such as an optical disc including a compact disc, CD or a digital versatile disc, DVD) in which data are nominally stored in a plurality of sectors have a defined sector size containing a first total number of bits. A number of altered sectors are formed on the medium each having a second total number of bits different from the first total number of bits. The altered sectors will provide readback data at a different rate than a nominal rate determined by the defined sector size. The altered sectors are used to verify the medium as being an authorized copy and prevent unauthorized copying efforts.

Abstract: Method for determining and cataloguing a digital data file fingerprint. A data file, such as an audio file, is converted into digital format. The file is then sampled using at least one reference value. From the occurrences of the samples in the digital data file being equal to the reference value, a fingerprint is determined. This fingerprint is provided to a digital data file fingerprint database, along with proprietary and other related information. Users may then quickly ascertain the proprietary information from a data file through accessing the database with a fingerprint. Furthermore, users may detect whether or not a data file has been manipulated, such as compressed using modern compression technology, by comparing a fingerprint of the suspect data file with an original fingerprint found in the database.

Abstract: Method and apparatus for tracking layers in a multi-layer optical disc. The disc includes a first layer which stores a first set of user data and a table of contents (TOC) for the disc. A second layer stores a second set of user data and an identifier tag which identifies the second layer as corresponding to the first layer. The identifier tag can comprise a portion of, or a complete copy of the TOC, or can comprise a reference value which, among other things, identifies a revision level of the second layer. Preferably, the first layer is also provided with a reference value. In this way, a database or other mechanism can be used to track the history of the various layers of the disc. Stampers form the respective layers and the ID tags further serve to ensure correspondence thereof in the formation of the disc.

Abstract: A recordable medium, an apparatus for forming the medium and a method for using the medium to support media authentication and copy protection efforts. A blank recordable comprises a plurality of concentric tracks arranged to form an addressable data recording area. Embedded within the data recording area is a non-recordable zone at one or more selected addresses. The non-recordable zone (recordable medium identification, or RMID zone) is configured to permit an attempted recording operation to record data to the zone, as well as to prevent successful readback of the data during a subsequent readback operation. An embossment is preferably supplied to the RMID zone such as a metalized layer of pits and lands, a layer of optically contrasting marks within the recordable medium, or a layer of dye. The embossment interferes with the ability to readback the data that was attempted to be written to the zone.

Abstract: A data storage medium (230, 400) and associated method (500, 520), apparatus (250, 430) and application routine (110, 524) for authenticating the medium as an authentic copy. The medium (such as a prerecorded or recordable optical disc) is formatted so that a predefined relationship is established (502) between physical locations of at least first and second addressable data sectors (220) prior to recording of data to the sectors (506). The predetermined relationship will be present in an authorized copy of the medium (330) but not in an unauthorized duplicate (332), allowing an application routine to grant or deny access (532, 534) to remaining portions of the medium based on the presence or absence of the detected relationship. The predetermined relationship is further used to embed a forensic data payload to serve as a digital fingerprint on the medium.

Abstract: An optical disc in which hidden data are stored for forensic tracking or copy protection purposes. This disc includes a contiguous user data portion comprising a set of user data samples which, when accessed by a readback system, generates a human detectable output. The disc further includes a null zone adjacent the contiguous user data portion comprising a sequence of user data fields storing a set of user data samples which, when accessed by a readback system, generates an output with a specified signal to noise ratio so as to be substantially undetectable by a human, wherein hidden data are written to at least selected ones of the user data fields of the null zone to convey a specified informational message related to the optical disc, the specified informational message undetectable by a human when the null zone is accessed by the readback system.

Abstract: An optical disc having a plurality of user data written to the disc from a lead-in zone to a lead-out zone, the disc comprising a plurality of control display data composed of a plurality of subcode registers, each having a value, where the control display data are written to the disc interposed with the user data and written to the lead-out zone and hidden data encoded within one of the subcode registers in the lead-out zone. The p-bit register in the lead-out zone of the optical disc required to toggle at a rate of 2 Hz. In one second, the optical disc reader reads 75 p-bit registers, therefore a perfect 2 Hz toggling cannot be achieved. The location of a p-bit state composed of a fewer number of p-bit sector is used to represent a bit value of hidden data.

Abstract: Method and apparatus for preventing unauthorized replication of a digital data file. A plurality of second data set samples are substituted for a plurality of user data samples in a user data sequence to generate a combined data set. Error correction codes are calculated to correct errors in the combined data set. Uncorrectable errors are then intentionally written to the error correction codes corresponding to the second data set samples so that, during playback, the readback system conceals the corresponding second data set samples. An unauthorized copy of the digital data file will not include the uncorrectable errors; thus, the same readback system will output both the user data samples and the second data set samples, with the second data set samples interfering with the integrity of the user data samples.

Abstract: Apparatus and method for writing data to an optical disc, and for subsequently reading the data therefrom. A first modulation encoding scheme (MES1) is defined to encode input data as data symbols having nominal symbol lengths over a first range. A second modulation encoding scheme (MES2) different from the MES1 is further defined to encode input data as data symbols having nominal symbol lengths over a second range. Each symbol length of the second range appears in the first range. The MES1 is used to encode primary data written to the disc while the MES2 is used to encode secondary data inserted at selected locations for disc authentication purposes. A readback system includes a primary decoder which decodes and outputs the primary data, and a secondary decoder which searches for a leading synchronization pattern which, when detected, allows remaining portions of the secondary data to be decoded.

Abstract: Apparatus and method for recording data to an optical disc to prevent unauthorized duplication of the disc. The disc includes a data placement zone to which first data are written at a first data rate as the disc is rotated at a selected linear velocity. The disc further includes a velocity disruption zone to which second data are written at a second different data rate as the disc is rotated at the selected linear velocity. The variation in frequency between the first and second data rates preferably causes a readback system to lose frequency lock on the second data during a continuous access operation on the first and second data. An unauthorized disc can also be detected by comparing the disc linear velocity as the second data are accessed to a target linear velocity. Access to the disc can be denied when a velocity mismatch is detected.