Abstract: A magnetic recording disk with pre-patterned surface features of elevated lands and recessed grooves or trenches, like a discrete-track media (DTM) or bit-patterned media (BPM) disk, has a planarized surface. A multilayered disk overcoat is used to protect the recording layer, and at least one of the overcoat layers functions as a stop layer for terminating a chemical-mechanical polishing (CMP) process that substantially planarizes the disk. All of the layers of the multilayered overcoat are located above the lands, but none of the overcoat layers, or a number of layers less than the number of layers over the lands, is located above the recesses.

Abstract: An optical disk data storage system uses an optical disk that has a plurality of substrates, each of which has a data surface. The laser light beam from the system is maintained on the data tracks of a selected one of the spaced-apart data surfaces by the use of tracking marks contained on the data surfaces. The system has a controller that identifies the type of data tracking used on the data surfaces from recorded tracking type information.

Abstract: A multiple recording layer rewriteable phase-change optical disk and disk drive uses a reverse writing type of reversible phase-change material as the recording layer nearest the incident laser light. The disk has a light-transmissive substrate onto which the laser light is incident. The substrate supports at least two spatially-separated multilayer recording stacks, each stack including an active recording layer of reversible or rewriteable phase-change material. The recording stack located nearest the substrate on which the laser light is incident includes a reverse writing type of reversible phase change material, i.e., a phase-change material with an amorphous starting phase that is recorded onto by laser heating that converts data regions to the crystalline phase.

Abstract: A multiple data layer optical medium, such as an optical disk, has a plurality of substrates, each of which has a data surface. The laser light beam from the optical data recording system is maintained on the data tracks of the two spaced-apart data surfaces by the use of tracking marks contained on the data surfaces. One of the data surfaces includes recorded information that identifies the type of tracking marks present.

Abstract: An optical data storage system comprises a multiple data surface medium and optical head. The medium comprises a plurality of substrates separated by a light transmissive medium. Data surfaces are located on the substrate surfaces. A layer of a semiconductor material is deposited onto each of the data surfaces. The thickness of the semiconductor layer determines the amount of reflectivity for each of the data surfaces.

Abstract: An optical data storage system comprises an optical disk drive and a multiple data surface magneto-optical medium. The medium comprises a substrate, a first dielectric layer, a first magneto-optical data layer, a second dielectric layer, a transmissive member, a third dielectric layer, a second magneto-optical data layer, a fourth dielectric layer, and a reflector layer. The thicknesses of the magneto-optical and dielectric layers are selected to maximize the magneto-optical read out signal received from the data layers. The disk drive includes a phase retarder for improving the signal from the magneto-optical data layers.