Abstract: An exemplary hard disk (HD) track has a full overhead section followed by user sections interleaved with intervening partial overhead sections that are too short for an HD drive (HDD) to attain sufficient timing lock using only one partial overhead section, but long enough for the drive to attain sufficient timing lock using multiple partial overhead sections to read user data from the user section immediately following the partial overhead section where sufficient timing lock is attained. The drive begins, but does not finish, attaining timing lock based on the first partial overhead section, but the drive does finish attaining timing lock based on the last partial overhead section. The drive can also read user data in subsequent user sections by maintaining or re-attaining sufficient timing lock using each successive partial overhead section. Increased user data storage is achieved without significantly impacting average latency of HDD read sessions compared to conventional HD drives.

Abstract: A small-sized, large-capacity optical disk is provided which is superior in portability. The optical disk has a diameter less than 64 mm and a thickness less than 0.8 mm. Tracks are formed with a pitch less than 0.6 ?m, and the record area is divided into a plurality of zones alone the radium. The optical disk can store more than 650 MB of compressed data.

Abstract: The present invention relates to a skew control method and a skew control unit by which stable skew control can be performed with a simple configuration without the need for a dedicated skew sensor. Focus drive voltages V1 and V2 are measured at a plurality of points P1 and P2 set by moving an optical pick-up 31 in the radial direction of an optical disc 2 in a state where a focus servo of the optical pick-up 31 is ON, and skew angle control is performed so that V1 and V2 are equal to each other.

Abstract: An optical disc medium 10 having a wobbled track groove 12 includes three wobble patterns including a flat wobble pattern, a positive pulse wobble pattern, and a negative pulse wobble pattern. In the flat wobble pattern, the amplitude of the wobble from the lengthwise direction of the track groove is zero such that the track groove is flat. In the positive pulse wobble pattern, the amplitude of the wobble from the length-wise direction of the track groove is positive such that the track groove is wobbled in a first direction perpendicular to the length-wise direction. Further, in the negative pulse wobble pattern, the amplitude of the wobble from the lengthwise direction of the track groove is negative such that the track groove is wobbled in a second direction opposite to the first direction. Then, three data values can be recorded using three distinctive wobble patterns.

Abstract: There are provided an optical disk, a magneto-optical disk, a disk apparatus therefor, and a data recording method which can provide improved recording/reproducing characteristics and record durability without linear velocity dependency even if the data access speed is increased by increasing the channel clock frequency. In a disk device for recording data on an optical disk by using a phase change recording scheme, erasing means for erasing data on the optical disk, and recording means for recording other data on the optical disk after the data is erased are provided.

Abstract: In an information recording medium according to the present invention, a recording layer, a first layer, and a second layer are formed so that a thermal conductivity of the first layer that contacts one surface of the recording layer and a thermal conductivity of the second layer that contacts another surface of the recording layer are both lower than a thermal conductivity of the recording layer and a track pitch is in a range of 0.1 ?m to 0.5 ?m, inclusive.

Abstract: In a magneto-optical recording technique by which an improved domain expansion reading is achieved, a mark region is recorded as a sub-mark portion and an adjacent sub-space portion, wherein the sum of predetermined first and second lengths of the sub-mark and sub-space portions, respectively, is changed in dependence on the pattern of marks and spaces. The write strategy enables writing a long run length with sub-mark and/or sub-space lengths selected independent of the channel bit length, such that a long run length can be written with few well-chosen domains with a stray field larger than the minimum field for MAMMOS readout. In this way, differences in readout conditions for all combinations of short and long run lengths can be eliminated, resulting in substantially improved power margins for random data.

Abstract: A recording and reproducing apparatus for recording a program including video and/or audio information on a removable recording medium includes an interface, a recording unit, a reproducing unit, and a controller. The interface is configured to receive reservation information for recording the selected program. The reservation information includes maximum bit rate information. The recording unit is configured to record the reservation information on the removable recording medium. The reproducing unit is configured to reproduce the reservation in formation from the recording medium when the removable recording medium is loaded. The controller is configured to record the selected program on the removable recording medium based on the reservation information.

Abstract: A medium for optical recording is disclosed, from which recorded information is reproduced by a laser beam. The medium includes a disk board having a recording surface, and multiple pits in the recording surface. The pits are included in cells having equal size and varying pit-occupancy rates dependent on the recording information, the pit-occupancy rate being the ratio of area of the pit to area of the corresponding cell. The depths H of the pits, the wavelength ? of the laser beam, and the refractive index n of the board are related as, ?/6n<H<?/4n.

Abstract: Plural grooves or lands formed in an information recording carrier include at least a wobbling region and data is recorded wobblingly in this wobbling region by phase shift modulation while recorded digitally with a single or multiple waves as a channel bit.

Abstract: Theft, distribution, and piracy of digital content on optical media (software, video, audio, e-books, any content of any kind that is digitally stored and distributed) is often accomplished by copying it directly to another disc using commonly available copy tools and recordable optical media, or the copying of media to another mass manufactured disc. Methods which cause the copy process to become lengthy and inconvenient, or which produce copies that are significantly measurably different from the original and therefore be recognizable as copies, deter or prevent an unauthorized individual from making copies. This is accomplished by modifying the optical path of an optical medium to include regions of selective distortion. This, in turn, modifies the read operation of the data in the regions, which can be used to identify and authenticate the medium.

Abstract: The present invention is directed to a recording/reproducing apparatus having a Read After Write function which simultaneously performs recording operation and reproduction operation, and is such that, in a reproducing system (120) of a tape streamer (100) which performs Read After Write operation for signals through a magnetic tape (105), the apparatus serves to distribute reproduction signals obtained from the magnetic tape by a first data distribution switch (133) to store signals thus distributed into frame memories (135A), (135B) of 2 channels, and to distribute a recording signal from a recording system (110) by a second data distribution switch (134) as cause signals of crosstalk signals included in reproduction signals to store signals thus distributed into frame memories to generate pseudo crosstalk signals of respective channels by crosstalk cancellers (136A), (136B) on the basis of reproduction signals and cause signals of respective channels which are read out from the frame memories to cancel, ev

Abstract: Management information is read from an information storage medium having the management information recorded thereon, the management information including track number information imparted to at least one track and group management information for managing as selective recording information one or a plurality of tracks as one group. Judgment is then made upon whether the group management information is included in that management information. A display mode is changed depending on a case where the group management information is recorded and a case where it is not recorded, and it is then displayed in a displaying device.

Abstract: A method for compensating an offset of a disk drive which is accomplished by recording actual spin jitter while performing track following, extracting a DC component from a recorded actual spin jitter, and compensating for an offset of a spindle speed based on an extracted DC component.

Abstract: A system provided for protecting a disk drive from impact damages. More specifically, a disk drive is provided that includes an accelerometer interconnected to a printed circuit board that detects free fall of the disk drive. In addition, the velocity of spinning disks of the disk drive is also monitored to assess changes in velocity thereof that may indicate the presence of a tumbling condition. Furthermore, the change in acceleration measured by the accelerometer is monitored to prevent false indications of free fall due to common vibrations. Thus an enhanced system is provided that protects disk drives from the effect of free falls under a wide variety of conditions and allowing for drops from shorter distances to be identified.

Abstract: High speed access to an information recording medium is possible by preparing information relative to a lower level recording unit, e.g., a fragment, which is set smaller than a higher level recording unit, e.g., a session. A fragment identifier, typically, a fragment number is assigned to each fragment, sequentially and in ascending order. A fragment number (greatest fragment number) that is greater than any other fragment number in the session is recorded in the information recording medium for each session. When reproducing a desired fragment, a controller acquires the greatest fragment number of each session sequentially from the first session, and compares the greatest fragment number of the session with the fragment number of the desired fragment. When the greatest fragment number that is equal to or greater than the fragment number of the desired fragment is found, the desired fragment is searched for from the top of the session.

Abstract: An optical pickup apparatus for reproducing information from an optical information recording medium or for recording information onto an optical information recording medium, is provided with a first light source for emitting first light flux having a first wavelength; a second light source for emitting second light flux having a second wavelength, the first wavelength being different from the second wavelength; a converging optical system having an optical axis and a diffractive portion, and a photo detector; wherein in case that the first light flux passes through the diffractive portion to generate at least one diffracted ray, an amount of n-th ordered diffracted ray of the first light flux is greater than that of any other ordered diffracted ray of the first light flux, and in case that the second light flux passes through the diffractive portion to generate at least one diffracted ray, an amount of n-th ordered diffracted ray of the second light flux is greater than that of any other ordered diffracted

Abstract: An information recording medium according to the present invention includes a recording layer that is formed of a single layer of a single type of recording material and is directly sandwiched by a pair of resin layers, the information recording medium being constructed so that at least one resin layer out of the pair of resin layers deforms due to deformation of the recording layer that is caused by irradiation with laser light for recording data and a track pitch is in a range of 0.1 ?m to 0.5 ?m, inclusive, wherein the pair of resin layers are formed with respective Young's moduli in a range of 415 MPa to 7100 MPa, inclusive.

Abstract: A servo control apparatus and method controls systems at least partially on the basis of an observable variable that has an absolute value functional relationship with the controlled variable and does not change sign for positive and negative variations from a nominal value. When applied to the positional control of an object, the control system observes a value of a position error signal and maps that signal to two different potentially correct displacement values. Two estimators within the control system are initiated, one using the positive displacement and the other using the negative displacement, and the two estimators each predict the future position of the object and the corresponding position error signal for each estimated position. A new position error signal is detected and compared to the two estimated position error signals.

Abstract: Apparatus and methods for controlling the sensing of bit lines which facilitates the distribution of bit line charging current to be distributed any time, and facilitates the fast raising of the sense modes to full logic levels. An embodiment is comprised of a plurality of bit storage capacitors, a folded bit line for receiving charge stored on one of the capacitors, having bit line capacitance, a sense amplifier having a pair of sense nodes for sensing a voltage differential across the sense nodes, apparatus connected to the bit line and the sense nodes for imperfectly isolating the sense nodes from the bit line whereby current can leak therethrough, apparatus for enabling the sense amplifier and for disabling the isolating apparatus and thereby removing the isolation between the sense amplifier and the bit line, whereby current passing through the sense amplifier to the sense nodes is enabled to charge the bit line capacitance through the isolating apparatus to predetermined logic voltage level.