Abstract: A method and apparatus may include determining a failure of a drive. The drive comprises a plurality of platters, each platter comprises two half-platters, and data of the drive is stored via erasure encoding. The method can also include rebuilding a portion of the drive upon which the failure occurred, wherein other portions of the drive are not rebuilt.

Abstract: An optical information medium comprises a pair of discs which are bonded to each other, an optical recording layer provided on at least one of the discs, and a reflecting layer formed on an upper side of the optical recording layer. The optical information medium further includes an adhesive for bonding the pair of discs provided on the reflecting layer, wherein the adhesive has a thickness ranging from 10 to 80 ?m. A protecting layer is provided on the upper side of the reflecting layer wherein the pair of discs may be bonded by the protecting layer. The optical recording layer, reflecting layer and protecting layer may be directly sequentially provided on the disc but another substrate layer may be inserted between these layers. There is employed, as the adhesive, those including a reactive curing resin or a hot melt material, and it is preferable that the shrinkage rate of the adhesive be less than 15%.

Abstract: An optical disk 100 is provided with a hub 3 at the central portion of a substratel. A relationship Y/X?0.015, preferably Y/X?0.05 is satisfied where X is the projected area of the substrate 1 and Y is a contact area between the hub 3 and the substrate 1. As result, no slippage occurs between the hub 3 and the substrate 1 even when they are rotated at high speed than conventional. With this higher rotational speed, the data transfer rate is improved, and irregular rotation and the camming are suppressed, thereby reducing tracking errors and write/read errors.

Abstract: An optical information recording medium is provided with a plurality of information layers (2, 3), each of which has a sector structure in which a data area (8, 12) is divided in the circumferential direction by a sector address (9, 13). The positions of the sector addresses (9, 13) of the respective information layers (2, 3) coincide in the circumferential direction. This can prevent errors during reproduction caused by the effect of other information layers and stabilize recording characteristics, resulting in an increased recording capacity of a rewritable recording medium having a plurality of information layers with a sector structure.

Abstract: An optical disc for storage and retrieval of digital data, and a system and method for protecting the optical disc is disclosed. The optical disc has projections or embossments on one or both surfaces. When the optical disc is placed on a substantially flat surface such as a tabletop or a desktop, the projections act as pedestals that elevate the optical disc above the flat surface. The resulting gap or clearance helps prevent damage to the optical disc caused by contaminants on the flat surface or by defects in the flat surface. The projections are sized to provide adequate clearance between the disc and the flat surface, while minimizing interference between the projections and components of optical disc readers and drives. The optical disc may also include one or more depressions that are sized and configured to receive projections from another disc, which facilitates stacking of the optical discs.

Abstract: A system for storing a set of disks, each disk having a first major surface and a second major surface opposed to the first major surface and defining a uniform central aperture. The system comprises a set of spacers, any one of which is adapted to cooperatively engage any of the others. A first one of the spacers is placed on the first major disk surface in a first position and orientation and a second one of the spacers engages with the first spacer by being placed on the second major disk surface in a position and orientation coincident with the first position and orientation except for being spaced apart from it by the thickness of the disk. In this configuration, the first one of the spacers is retained on the first major surface and the second one of the spacers is retained on the second major surface.

Abstract: A system for storing a set of disks, each disk having a first major surface and a second major surface opposed to the first major surface and defining a uniform central aperture. The system comprises a set of spacers, any one of which is adapted to cooperatively engage any of the others. A first one of the spacers is placed on the first major disk surface in a first position and orientation and a second one of the spacers engages with the first spacer by being placed on the second major disk surface in a position and orientation coincident with the first position and orientation except for being spaced apart from it by the thickness of the disk. In this configuration, the first one of the spacers is retained on the first major surface and the second one of the spacers is retained on the second major surface.

Abstract: An optical information medium comprises a pair of discs which are bonded to each other, an optical recording layer provided on at least one of the discs, and a reflecting layer formed on an upper side of the optical recording layer. The optical information medium further includes an adhesive for bonding the pair of discs provided on the reflecting layer, wherein the adhesive has a thickness ranging from 10 to 80 &mgr;m. A protecting layer is provided on the upper side of the reflecting layer wherein the pair of discs may be bonded by the protecting layer. The optical recording layer, reflecting layer and protecting layer may be directly sequentially provided on the disc but another substrate layer may be inserted between these layers. There is employed, as the adhesive, those including a reactive curing resin or a hot melt material, and it is preferable that the shrinkage rate of the adhesive be less than 15%.

Abstract: A disk medium and a method of manufacturing the disk medium are disclosed. The disk medium includes a first disk member having a penetrating hole, and a second disk member having a projecting portion, wherein the projecting portion is placed within the penetrating hole of the first disk member to form the optical medium. The method includes forming a first disk member having a penetrating hole, forming a second disk member having a projecting portion, and positioning the projecting portion of the second disk member within the penetrating hole of the first disk member, whereby the first and disk members are combined to form an optical medium.

Abstract: A substrate disk consists of a first and a second substrate connected to one another wherein the first and second substrates have center holes. The first substrate has at least one projection positioned at the circumference of the center hole and projecting from the face of the substrate. In a preferred embodiment an annular projection surrounding the center hole is provided.

Abstract: A protected recording medium generally in the form of a disk and in one embodiment corresponding to a compact disk (CD) is provided with an annular spacer on one side thereof near the periphery thereof that will elevate an exposed downward recordable region of the medium far enough above a flat surface onto which the medium is placed to avoid contact with dust and dirt on that surface. The “upper” surface of the medium is also provided with an annular groove at a radial position corresponding to that of the spacer just noted, whereby two or more such protected recording media can be stacked one upon the other such that lateral movement of one relative to the other will be precluded.

Abstract: A disk medium and a method of manufacturing the disk medium are disclosed. The disk medium includes a first disk member having a penetrating hole, and a second disk member having a projecting portion, wherein the projecting portion is placed within the penetrating hole of the first disk member to form the optical medium. The method includes forming a first disk member having a penetrating hole, forming a second disk member having a projecting portion, and positioning the projecting portion of the second disk member within the penetrating hole of the first disk member, whereby the first and disk members are combined to form an optical medium.

Abstract: A double sided (or higher multiple sided) data storing compact disc for optically recorded data has data surfaces that are separated by a thin film of wavelength selective material that passes light of one frequency and reflects light of a second (or multiple) frequency. The thin film either passively relies upon the inherent interference between light signals reflected from its upper and lower surfaces or is an active material that reflects light of one frequency and transmits light of a second frequency. A further aspect of the present invention is the method for the manufacture of such a multi-surfaced disc.

Abstract: The optical recording medium of this invention includes: a first substrate having a first information surface; a semitransparent reflection film formed on the first information surface of the first substrate; a second substrate having a second information surface; a reflection film formed on the second information surface of the second substrate; and an adhesive layer for adhering the first substrate and the second substrate so that the first information surface and the second information surface face each other, wherein the thickness of the first substrate is 0.56 mm or more, the thickness of the adhesive layer is 30 .mu.m or more, and the total thickness of the first substrate and the adhesive layer is 0.68 mm or less.

Abstract: A colorimetric device, particularly suitable for a camera, that provides reliable color data so that a subject field is photographed with appropriate color balance. A CPU reads out sensor data D.sub.B, D.sub.R corresponding to red (R) and blue (B) light components of an incident light from the subject field a light sensor or photometric element disposed in the camera. Next, the CPU compares the sensor data D.sub.B of the B color component, and the sensor data D.sub.R of the R color component, with a predetermined standard value K1, and when it is determined that either of the sensor data D.sub.B of the B color component, or the sensor data D.sub.R of the R color component, is below the standard value K1, a "measurement impossible" display is performed for a color temperature T and a balance value LB. On the other hand, if both sensor data D.sub.B, D.sub.R are greater than the standard value K1, the color temperature T and the light balance value LB are calculated by a calculation circuit.

Abstract: A system and method is disclosed for assembling a pre-formatted top half and a pre-formatted bottom half of a disk platter, and for further assembling pre-formatted disk platters into a multi-platter MO disk drive, with the servo sectors in a predetermined rotational alignment and with the tracks in good radial alignment. Because of the known rotational alignment of the servo sectors, it is possible to have independent verification of the operation of the flying MO head switch. This independent verification prevents data corruption due to an unreliable flying MO head switch.

Abstract: An optical information recording medium which can be played back by both a playback system for an SD (Super-density Disk) and a playback system for an HDMCD (High Density Multimedia Compact Disk), or by both the playback system for the SD and a playback system for a CD (Compact Disk).

Abstract: An interlocking disk apparatus for preventing disk slip in a disk stack of a magnetic or optical disk drive is provided. A textured region within the inner diameter of the disks in the disk stack is forced in tight contact with a conformable adjacent surface, such as a spacer ring, clamp plate, and/or hub flange. The textures on the disks penetrate into and/or through the conformal coatings on the adjacent surfaces, resulting in mechanical interlock that inhibits in-plane displacements of the disks from shock and generally improving interfacial contact of the surfaces within the disk stack, thus requiring lower clamping pressures to the disk stack and resulting in greater disk flatness and minimizing disk distortion. Electrostatic Discharge within the disk stack is prevented by diffusing conductive materials into the polymer conformal coating to increase its electrical conductivity.

Abstract: The optical recording medium of this invention includes: a first substrate having a first information surface; a semitransparent reflection film formed on the first information surface of the first substrate; a second substrate having a second information surface; a reflection film formed on the second information surface of the second substrate; and an adhesive layer for adhering the first substrate and the second substrate so that the first information surface and the second information surface face each other, wherein the thickness of the first substrate is 0.56 mm or more, the thickness of the adhesive layer is 30 .mu.m or more, and the total thickness of the first substrate and the adhesive layer is 0.68 mm or less.

Abstract: A multi-layered disk which can improve a data recording density and also can record signals and allow reading and reproduction of the recorded signals in good conditions and a recording system as well as a reproducing system using the same and a multi-layered recording disk in which a plurality of data recording surfaces are laminated. In a band wherein, against an MTF level obtained when a read light is on-focus to one of the data recording surfaces, an MTF level obtained when the read light is defocusing to other data recording surfaces is 1/N (N is a real number larger than 1), data signals are recorded in each of the data recording surfaces. A distance t between each data recording surface, numerical aperture NA of an objective lens guiding a read light to any of the data recording surfaces, a wavelength.lambda. of the read light, an equivalent refractive index n between each data recording surface, and a number i of laminated data recording surfaces satisfy the following relation:1.4 n.lambda./(NA).sup.

Abstract: An optically readable data storage medium includes a thin film data carrier fabricated from first and second juxtaposed plastic layers. A microembossed data surface is positioned within an interface zone and includes physically displaced surface elements which encode digital data. An adaptor temporarily receives and supports the thin film data carrier from below and includes a centrally located aperture geometrically compatible with a standard CD player spindle to enable the adaptor to be supported and rotated by the spindle. The adaptor includes a refraction zone having an area and a location underlying the microembossed data surface to enable the light beam from the light source of the CD player to be focussed onto the rotatable data surface. The reflected light beam modulated by the digital data encoded within the microembossed data surface is intercepted and converted to an electrical signal by the CD player optical readout device.

Abstract: A double-side optical disc formed by a pair of optical disc halves bonded together, and a process for producing the double-side optical disc. An adhesive is applied to the disc halves, which are then bonded together at an angle relative to each other in which the direction of the adhesive flow on one disc half will intersect the direction of the adhesive flow on the other disc half. In this manner, satisfactory flatness of the optical disc may be achieved without being affected by surface irregularities of the adhesive layer.

Abstract: Double sided optical memory disks are produced by dropping a viscous adhesive material hardenable by ultraviolet radiation at predetermined longitudinal intervals onto an elongated cloth material of uniform thickness thereby causing the adhesive material to become absorbed by and contained in the cloth material, thereafter placing this cloth material sandwichedly between two optical disk pieces each containing a recording layer, thereafter applying pressure between these pieces such that the sandwiching pieces remain separated uniformly by a predetermined separation distance, and thereafter applying ultraviolet radiation to and thereby hardening the adhesive material while the disk pieces are maintained at the uniform separation distance.