Abstract: Time-based servo positioning systems, methods, formats, and data recording media used in association with the same, employing full amplitude recording signals to improve the available signal as media thicknesses decrease.

Abstract: A secure computing environment in which a computer automatically operates in a full-access data storage mode when it detects the presence of a secure removable storage device. In full-access mode all data written to removable storage device is encrypted with a cryptographic key and the user is given access to sensitive if authorized. Otherwise, the computer operates in a restricted-access mode in which the user is unable to write to the removable storage device and is unable to access sensitive data. The invention detects security information on the data storage device and generates a cryptographic key from the security information. The security information can be a function of the unique format characteristics of the underlying storage medium, a unique identifier retrieved from an electronic circuit embedded within the removable storage device or a serial number etched on the storage device during manufacturing.

Abstract: The invention is directed toward techniques for creating molded substrates for use in various different data storage media. The molded substrates have improved thickness profiles that can improve media quality, and in some cases facilitate higher data storage densities. In many cases, the improved thickness profile is a thickness profile that has improved flatness. Mechanical flatness or optical flatness can be achieved. In particular, optical flatness is desirable for substrates used in holographic data storage media having a sandwiched construction.

Abstract: A magnetic recording medium exhibits reduced magnetic flux modulation and improved signal-to-noise ratio. The magnetic recording medium may take the form of a magnetic tape or a magnetic disk. Providing a magnetic recording layer with a more uniform thickness can improve the magnetic flux modulation characteristic. For example, the magnetic recording medium may have a coercivity of greater than or equal to 2000 Oerstads with a magnetic flux modulation characteristic having a one sigma standard deviation of less than 0.06. In some cases, the magnetic flux modulation characteristic may have a one sigma standard deviation of less than 0.05, or even 0.04. Reduced magnetic flux modulation can support increased storage densities.

Abstract: Perpendicular magnetic media are described for use in magnetic recording and data storage. Seed layer compositions are described which can facilitate perpendicular magnetic anisotropy in subsequently deposited magnetic layers. In particular, nickel-iron-chromium (NiFeCr) alloys or nickle-chromium (NiCr) alloys can be used as seed layers which cause a subsequently multi-layered magnetic stack to assume perpendicular magnetic anisotropy. In this manner, high perpendicular magnetic anisotropy can be achieved and storage densities of media may be increased.

Abstract: The invention is directed to a magnetic storage medium recorded with an amplitude-based servo pattern in which one or more first servo windows positioned above a centerline of a servo track have a different width than one or more second servo windows positioned below the centerline. The first servo windows may be larger or smaller than the second servo windows. In either case, by detecting the widths of the servo windows and detecting signal amplitude as a servo head passes relative to the servo track, servo tracking can be achieved without the use or need for additional synchronization marks in the servo pattern.

Abstract: Servopositioning data is written onto a linear recording medium such that a position error signal is intentionally created. Precise control over the distance between servo signals simulates position error signals at any frequency or magnitude. Drives that normally assume that such distance is constant perceive the simulated position error signals as vertical tape motion. Thus, a servo writer can create such signals at pre-determined levels within the servo pattern.

Abstract: In general, the invention provides two-sided magnetic data storage tape comprising azimuthal magnetic transition layouts that can substantially reduce demagnetization of recorded magnetic transitions on the surfaces of the tape. The invention specifically balances the goal of simplified media manufacture with the goal of reducing or avoiding media degradation when the tape is spooled. The two-sided magnetic data storage tape defines a substantially similar easy axis of magnetic anisotropy on a first and a second side of the tape, which can simplify media manufacture. Recorded magnetic transitions on the opposing sides of the tape define azimuths that are substantially different, which can help avoid media degradation when the tape is spooled.

Abstract: Multilayer magnetic recording medium which is suitable for high recording densities and the recording of digital data, has very good electromagnetic recording properties and good surface smoothness and can absorb a large amount of lubricant in the lower layer and has at least one upper magnetic recording layer less than 0.5 ?m thick and at least one lower layer which contains a magnetically soft pigment.

Abstract: Techniques for precisely controlling the size of particles in a coating solution delivered to a coating apparatus involve continuous classification of coating particle size using a tangential flow filter assembly. The techniques may be particularly useful in the preparation of coating dispersions for manufacture of magnetic recording media. A classification technique makes use of a tangential flow filter assembly that permits delivery of coating particles below a maximum size threshold to a coating path. The filter assembly may be disposed in a circulation path that includes one or more processing devices to reduce the size of coating particles carried by a coating solution. The filter assembly enables coating particles above the maximum size threshold to be recirculated through the circulation path and subjected to repeated processing to reduce particle size to a desired size range.

Abstract: The invention is directed to a high pressure fluid processing device for shearing particles in a fluid mixture. The fluid processing device makes use of annular flow paths. For example, a fluid mixture can be separated into two flow paths which are introduced to first and second annular flow paths on opposite sides of a flow path cylinder. The two annular flow paths flow toward one another through the cylinder, and meet one another within the cylinder. An outlet extends through the cylinder where the two annular flow paths collide allowing the fluid mixture flowing down the annular flow paths to be expelled through the gap.

Abstract: Perpendicular magnetic media are described for use in magnetic recording and data storage. For example, a magnetic medium may include a substrate, an amorphous underlayer formed over the substrate, a seed layer formed over the amorphous underlayer, and a multi-layered magnetic stack formed over the seed layer. In this manner, high perpendicular magnetic anisotropy can be achieved and storage densities can be increased.

Abstract: In one embodiment, a holographic data storage medium includes a substrate, a holographic recording material, and an optically detectable tracking pattern on the medium. The substrate may have first and second substrate portions. The holographic recording material may be a photopolymer, and the medium may have a sandwiched construction, where the holographic recording material is sandwiched between the first and second substrate portions. The optically detectable tracking pattern may be replicated on at least one of the substrate portions. Alternatively, the optically detectable tracking pattern may be recorded as a holographic grating in the holographic recording material. The tracking pattern may facilitate the ability to pinpoint the location of the holographic bit maps on the holographic medium to within a fraction of a micron.

Abstract: In general, the invention is directed to techniques for reducing deformation of tape in data tape cartridges during storage to promote dimensional stability and increased tape longevity. The techniques involve controlling the winding tension applied to a tape during a final winding pass prior to unloading a data tape cartridge containing the tape from a drive. Excessive winding tensions can produce strain and compression on a tape pack, causing the tape to deform over time. Applications of reduced winding tension during the final pass provide reduced tape pack tension during periods in which the data tape cartridge is not used.

Abstract: A data storage tape cartridge includes a housing having a surface resistivity in a range of approximately 106 ohms/square to approximately 1012 ohms/square, at least one tape reel rotatably disposed within the housing, and a length of magnetic storage tape wound around the at least one tape reel.

Abstract: A single reel data storage tape cartridge is described that includes a housing having a tape access window. A single tape reel assembly is rotatably disposed within the housing and includes a hub about which a storage tape is wrapped. A tape guide is disposed within the housing adjacent the single tape reel assembly, opposite the tape access window, and is configured to define a pathway of the storage tape from the single tape reel assembly to the tape access window and limit lateral motion of the storage tape.

Abstract: A magnetic tape recording system employing a single bump read-while-write head, methods of minimizing crossfeed signals between the read and write channels of magnetic tape recording systems, and electronic circuitry to implement such methods.

Abstract: A polyurethane having at least one anionic anchor group L, the anchor group L being covalently bonded to a polyether segment having at least one nitrogen atom in the polyurethane.

Abstract: The invention is directed to magnetic media that make use of plastic substrates. Various buffer layer compositions are described, which can be formed over the plastic substrate. One or more ferromagnetic recording layers are then formed over the buffer layers. The described buffer layers can function as encapsulating layers in order to encapsulate the plastic substrate and provide a barrier between subsequently deposited magnetic layers and the gases within the substrate. Also, the buffer layers can reduce stress in the media either by functioning as a stress reduction layer that promotes growth of the magnetic recording layer in low stress orientations, or by functioning as a stress compensation layer that balances the stress of the subsequently deposited magnetic layers.

Abstract: The invention is directed to a multi-connector memory card that includes a device connector and a connector that conform to a device connection standard and a host connection standard respectively. The dimensions of the memory card may substantially conform to dimensions of a memory card standard, such as a MultiMedia Card standard or a Secure Digital standard. A retractable sheath fits over a housing of the memory card to protect electrical contacts on the device-connector and the host connector. In particular, the retractable sheath that can be positioned in a first position to cover the host connector and expose the device connector, and a second position to cover the device connector and expose the host connector.