Abstract: A thermally-assisted recording (TAR) patterned-media magnetic recording disk drive has a perpendicular patterned-media disk with multilevel data islands and a laser capable of supplying multiple levels of output power to a near-field transducer (NFT). If there are only two cells in each island, each island is formed of an upper cell of magnetic material with a coercivity HC1 and a Curie temperature TC1, a lower cell of magnetic material with a coercivity HC2 and a Curie temperature TC2 greater than TC1, and a nonmagnetic spacer layer between the two cells. Each cell is formed of high-anisotropy material so as to have an anisotropy field greater than the magnetic write field. The TAR laser is capable of supplying at least two levels of output power to the NFT to allow the islands to be heated to two distinct temperatures so that the two cells in an island can be written so as to have either the same or opposite magnetizations.

Abstract: According to one embodiment, a data write control apparatus includes a magnetic disk, a write controller, and a retry controller. The magnetic disk includes a track in which data is recorded in sector unit. The write controller is configured to execute control to write a sector data block to a predetermined sector in the track. The retry controller is configured to execute control to retry a write process to a predetermined number of sectors to which data has been written and which include a first sector, and to manage the number of retries performed on each sector.

Abstract: A magnetic tape apparatus performs at least one of data reading processing and data writing processing on LTO wound around a reel. The magnetic tape apparatus causes the reel to rotate and move the LTO to a position at which the data writing processing or the data reading processing can be performed by a magnetic head. The magnetic tape apparatus is arranged along the width direction of the magnetic tape of LTO, which is driven, to detect medium abnormality that occurred in either a start-end or a stop-end in the width direction of the magnetic tape.

Abstract: An annular groove is provided to the rotary portion and/or the fixed portion in a bearing seal portion, and its cross section has a shape approximated by an arc. The annular groove is such that the relationship between the groove width W in a direction following the surface constituting a bearing seal portion and the groove depth Dg in a direction perpendicular to the surface constituting the bearing seal portion is Dg/W<0.4.

Abstract: A method of manufacturing a magnetic recording medium is provided, which include: forming a magnetic layer on the surface of a nonmagnetic substrate; forming a groove in which a nonmagnetic section is formed by etching a portion corresponding to a formation region of the nonmagnetic section in the magnetic layer and a magnetic recording section formed of the magnetic layer; applying a resin having an active energy ray curable functional group to the surface of the magnetic recording section so as to fill the groove; pressing a plate material against the resin so that the smooth surface of the plate material is in contact with the surface of the resin to make the surface of the resin smooth; removing the plate material from the resin; and forming the nonmagnetic section in the groove by etching and removing a portion located above the surface of the magnetic recording section in the resin having a smooth surface.

Abstract: A device for reading data recorded on a recording medium having multiple tracks, the device including: a receiver that receives designations of a number of data elements to be read; and a determination unit that determines an order of reading the data elements so that, no matter on which track of the tracks each of the data elements is recorded, the data elements are read in an order of recorded locations of the data elements in a direction along the tracks on which the data elements are recorded.

Abstract: According to one embodiment, a magnetoresistive element includes a stack and a pair of electrodes that allows electric current to flow through the stack in a direction perpendicular to a surface of the stack. The stack includes a cap layer, a magnetization pinned layer, a magnetization free layer provided between the cap layer and the magnetization pinned layer, a tunneling insulator provided between the magnetization pinned layer and the magnetization free layer, and a functional layer provided within the magnetization pinned layer, between the magnetization pinned layer and the tunneling insulator, between the tunneling insulator and the magnetization free layer, within the magnetization free layer, or between the magnetization free layer and the cap layer. The functional layer includes an oxide including at least one element selected from Zn, In, Sn and Cd and at least one element selected from Fe, Co and Ni.

Abstract: A method of performing information storage comprises the steps of providing a medium comprising a plurality of concentric rings for storage of information. The medium is written to by a process comprising simultaneously writing and erasing elements in at least two adjacent rings, respectively a first ring and a second ring. Subsequent to simultaneously writing and erasing elements in at least the first and second rings, simultaneously writing and erasing elements in a third concentric ring, wherein the third ring is adjacent the second ring.

Abstract: A method and apparatus to detect a defective sector include features of determining a first error value by counting the number of error symbols in first data read from a sector by using a head in an on-track state, and reading second data from the sector by off-tracking the head in a positive direction and third data from the sector by off-tracking the head in a negative direction in response to the first error value being equal to or greater than a first threshold value. Additionally, a second error value is determined based on the number of error symbols in the read second data and a third error value is determined based on the number of error symbols in the read third data. Accordingly, the sector is determined to have a defect by comparing an average of the second and third error values to a second threshold value.

Abstract: A method of performing a write operation in a disk device comprises storing multiple units of data in a first area of a buffer, wherein each of the units of data has a size that is different from a size of a corresponding target sector of a disk. The method further comprises transferring data from a first target sector to second and third areas of the buffer, and writing the data stored in the first area of the buffer and the data stored in the third area of the buffer to the first target sector.

Abstract: According to one embodiment, an apparatus for controlling a head includes a transmitting module and a controller. The transmitting module is configured to transmit a write signal to a magnetic head having a spin torque oscillator at the time of recording data. The controller is configured to supply a drive signal that has a level higher than the ordinary level for a prescribed effective time, to the spin-torque oscillator in response to an input write gate that instructs the recording of data. During a period other than prescribed effective time, the controller supplies a drive signal having the ordinary level to the spin-torque oscillator.

Abstract: A data recording apparatus and a data recording system of the present invention includes buffer memories 2a to 2c that accumulate data in a plurality of channels transferred from an external appliance on a channel basis, a data selector 3 that reads the data accumulated in the buffer memories 2a to 2c, and a data drive 4 that records the data read by the data selector 3 onto a magnetic tape, wherein the data selector 3 selectively reads the data accumulated in the buffer memories 2a to 2c, and outputs the data in an order of recording onto a magnetic tape in the tape drive 4. According to such a configuration, a data recording apparatus that can be realized at low cost and a recording system using the data recording apparatus can be provided.

Abstract: A hard disk drive (HDD) uses adaptive counting of writes to the data tracks to minimize the effect of adjacent track encroachment (ATE). The tracks are grouped into segments and a counter is associated with each segment, but the number of tracks in a segment varies or adapts depending on the number of writes to the segment. When the count for the number of writes to a segment reaches a threshold, the segment is divided into a number of segments with fewer tracks. The original segment no longer exists and does not require memory to store its count. This process continues until a segment reaches a predetermined minimum number of tracks. When the count for the number of writes to a segment with the minimum number of tracks reaches a threshold, all of the tracks in that segment, and tracks radially adjacent to and on both sides of the segment, are read and rewritten.

Abstract: Methods for certifying data retained by a tape cartridge in a tape library are shown. Error rates that are encountered when the tape cartridge is being read by a tape drive can be accounted for without actually reading data for data content retrieval. A record of the error rate can be stored in a medium auxiliary memory device associated with the tape cartridge. An older record containing a formerly accounted for error rate of read errors when the tape cartridge was formerly read can be accessed and compared with the record presently assessed. If there is a difference between the presently found error rate and the formerly found error rate an action can be executed if the difference exceeds a predetermined threshold.

Abstract: A disclosed device having a principle axis and including a magnetoresistive stack, the magnetoresistive stack having first and second opposing surfaces, the magnetoresistive stack including a free layer, a spacer layer, and a reference layer, wherein the spacer layer is positioned between the first and reference layer, the free layer includes magnetic material having a free magnetic orientation in a first plane; the spacer layer includes a nonmagnetic material; and the reference layer includes a magnetic material having a pinned magnetic orientation in a second plane, wherein the second plane is perpendicular to the first plane and parallel to the principle axis of the device; an insulating layer at least a portion of the outer surface of the magnetoresistive stack; a shielding layer surrounding at least a portion of the insulating layer; and a conducting layer, wherein the conducting layer provides electrical connection between the magnetoresistive stack and the shielding layer.

Abstract: According to one embodiment, a power management module of a storage device executes a process of stopping rotation of a disk storage medium by selectively using one of a first mode of stopping the rotation of the disk storage medium on condition that a media access command is not received during a predetermined time from last reception of a media access command, and a second mode of stopping the rotation of the disk storage medium on condition that a media access command which causes access to the disk storage medium is not received during a predetermined time from last reception of a media access command which causes access to the disk storage medium. In addition, the power management module executes a process of starting the rotation of the disk storage medium by selectively using one of a third mode and a fourth mode.

Abstract: According to one embodiment, a magnetic recording head includes a main magnetic pole, a shield, and a stacked structure body. The shield is provided to oppose the main magnetic pole. The stacked structure body is provided between the main magnetic pole and the shield. The stacked structure body includes a first magnetic layer, a second magnetic layer, and an intermediate layer. The first magnetic layer has coercivity lower than a magnetic field applied from the main magnetic pole. A size of a film surface of the second magnetic layer is larger than a size of a film surface of the first magnetic layer. The intermediate layer is provided between the first magnetic layer and the second magnetic layer and is made of a nonmagnetic material. A current is configured to pass between the first magnetic layer and the second magnetic layer.

Abstract: In a servo writer, a write signal generator circuit is configured to output a signal for writing a servo signal to a servo write head disposed to allow a magnetic tape to slidably contact therewith and configured to write the servo signal thereon, and a plurality of tape guides are configured to guide the magnetic tape supplied from a supply reel to the servo write head and to a take-up reel. The plurality of tape guides include a first tape guide disposed to contact with the magnetic tape at a position directly upstream of the servo write head and a second tape guide disposed to contact with the magnetic tape at a position directly downstream of the servo write head. Each of the first and second tape guides includes a guide roller rotatably supported by an air bearing and having a diameter of 19 mm or greater.

Abstract: A computer-implemented method and apparatus for detecting misalignment in a data storage stack by opening a first storage layer in the data storage stack, performing a plurality of accesses of the first storage layer, each of the plurality of accesses starting at a different offset, and determining an optimal offset based on a performance benchmark of each of the plurality of accesses.

Abstract: A process for producing a magnetic recording medium which can increase significantly yield and productivity is provided. Such a process for producing a magnetic recording medium includes a resist layer forming step which includes an immersing step of immersing a part of a non-magnetic substrate 31 in a resist solution 11 so that an inner circular domain 3 of an opening part is arranged above a liquid surface 11a of the resist solution 11 and a part of a data recording domain 4 is arranged under the liquid surface 11a of the resist solution 11, and a taking out step of taking the non-magnetic substrate 31 out from the resist solution 11, while rotating the non-magnetic substrate 31 immersed in the resist solution 11 around a rotation axis 37a extending in the direction of the thickness of the non-magnetic substrate 31 through the center of an opening part 37.

Abstract: A system and method are described for rendering Compact Discs (CDs) and Digital Video Discs (DVDs) unreadable. Embodiments comprise a frame, a guide for constraining motion of the frame with respect to a disc, and at least one scraping element. Scraping elements may be positioned to damage the disc volume descriptor while the frame moves in a constrained manner relative to the disc. The guide may comprise a spindle which engages the center hole of a disc to hold the frame in a radially-fixed position. A scraping element on the frame damages the disc as the disc rotates relative to the frame. The guide may be integrated, such that the frame comprises a slot through which the disc passes. A scraping element inside the slot damages a disc as it passes through. Embodiments are hand operated, not motorized, and some have no moving parts. Embodiments also function with non-optical media.

Abstract: This invention provides a magnetic recording medium evaluation apparatus and evaluation method which yield results having good correlation with error rate measurements even when comparing media with different structures. Signals from a function generator are recorded in a magnetic recording medium. The recording signals are also passed through a first digital filter to obtain ideal restored signals. Reproduced signals from the magnetic recording medium are sampled in synchronization with the output from the function generator, and the discrete signals are passed through a second digital filter to obtain restored signals. The outputs from the first and second digital filters are input to an operational amplifier, and the difference between the restored signals and the ideal restored signals is taken for each sampling of the recording signals. The signal-to-noise ratio of the ideal restored signal to the average of the absolute value of this difference is used to evaluate signal quality.

Abstract: Disc drive data recovery methods and systems that utilize off center track information are provided. A disc drive data track is illustratively read at a first position along a width of the data track and at a second position along the width of the data track. The data read from the track is stored and tagged with indications of the first and the second positions. The tagged data is optionally used to calculate average waveforms for each of the first and the second positions and to identify the average waveform having the highest signal-to-noise ratio.

Abstract: A method of writing a servo pattern of a hard disk drive includes measuring the speed of a head of the hard disk drive by reading a basic servo pattern written to only select ones of the data tracks of the disk, realizing a feedforward current profile when the difference between the actual speed of the head and a target speed of the head is within a predetermined range, and writing a reference servo pattern using the realized feedforward current profile. A final servo pattern is then written using the reference servo pattern.

Abstract: A data storage system includes recording media with a shingled track pattern of multiple data tracks in which mapped data bits are recorded. The mapped data are coherently aligned with one another across the multiple data tracks. A read head has an effective read head width that extends across the multiple data tracks and that is aligned to coherently read the mapped data bits. A read head output includes a non-binary multi-level amplitude summation of the mapped data bits.

Abstract: Injecting pad bits during a read operation to improve format efficiency is disclosed. In some embodiments, a pad sequence associated with error correction is not stored in a sector on a disk. Instead, the pad sequence is merged at a read channel with data stored in a sector that is accessed by the read channel.

Abstract: A method of performing data/information recording and retrieval utilizing a multilevel patterned magnetic medium, comprises providing a magnetic recording system including a read/write head and a multilevel patterned magnetic recording medium including a plurality of spaced apart data/information storage elements each comprising a stacked plurality n of magnetic recording cells with different magnetic properties and magnetically decoupled from overlying and/or underlying cells; providing relative movement between the write head and magnetic recording medium; and writing to the medium by supplying the write head with a modulated write current comprising a plurality n of pulses of different magnitudes while the head passes over each element, thereby applying n different magnetic field strengths to each element, such that the writing occurs in a single pass of the write head over each element.

Abstract: A signal-level calculating unit calculates a signal level based on a gain signal. A sample generating unit associates heater power with the signal level and generates samples used for determining the maximum power. An approximation-line determining unit determines an approximation line of the samples in a two-dimensional coordinate system. A line shifting unit shifts the approximation line and determines a line for determining a signal level when the heater power is increased by one step. A comparative-value calculating unit calculates a comparative value based on the line. An upper-limit determining unit compares the comparative value and an actual signal level, and determines whether the heater power has reached the maximum power.

Abstract: An arbitrary gap thin film magnetic recording head is fabricated by forming a substrate based on traditional vertical planar thin film head wafer technology which is designed to produce an integrated subgap and subpole substrate structure. The wafer is then processed into row bars to reveal, in a plane parallel to the transducing direction of the medium, the subgap and subpoles at the surface of the row bar and to bring the structure to a certain coil depth or gap depth. A flat or cylindrical contour may be utilized. This thin film subgap row bar is taken through a film deposition or growth process that deposits the magnetic film on a plane perpendicular to the wafer plane, horizontal planar processing, forming a surface film recording head where an arbitrary gap structure can be made in-between the subpoles and generally directly on top of the subgap.

Abstract: A method for using magnetic tape having damaged areas is disclosed. The method may include writing data to streaming magnetic tape, determining if the data write was successful, and responding to an unsuccessful data write by interrupting the data writing and advancing the magnetic tape forward a predetermined distance. Additionally, the method may include attempting to write data at the next location on the magnetic tape and determining if the data write was successful. The method may further include repeating the steps of advancing the tape, attempting to write, and determining whether the data write was successful following any determination that an attempted data write was not successful. The method may include further include resuming writing data to streaming magnetic tape at a location where a data write is determined to be successful.

Abstract: Extracting transducer position information from bit patterned magnetic media includes providing a magnetic storage medium having at least one data array with multiple discrete and separated recording bits and providing the transducer adjacent the data array. A readback signal dependent upon the multiple recording bits is generated with the transducer. Determining the transducer position information further includes generating at least a first position signal and a second position signal from the readback signal.

Abstract: A method and apparatus to read information from an information storage medium using a read channel, where that read channel includes a data cache. The invention generates an analog waveform comprising the information, and provides that analog waveform to a read channel, and generates a digital signal from that analog waveform using one or more first operating parameters. The method error corrects that digital signal at an actual error correction rate, and determines if the actual error correction rate is greater than an error correction rate threshold. If the actual error correction rate exceeds the error correction rate threshold, then the method captures the digital signal, stores that captured data in a data cache, reads that digital signal from the cache, generates one or more second operating parameters, and provides those one or more second operating parameters to the read channel.

Abstract: A magnetic recording and reproducing apparatus includes a magnetic head that has a spin-torque oscillator and a magnetic disk and the spin-torque oscillator detects a magnetic field from the magnetic disk and outputs a signal. A criterion used to determine the rotational speed of the magnetic disk, the frequency shift of the spin-torque oscillator produced by a magnetic field from the magnetic disk, a characteristic oscillation frequency of the spin-torque oscillator and the full-width at half maximum of an oscillation spectrum is given in order for a read signal output from the spin-torque oscillator to satisfy a desired signal-to-noise ratio and a magnetic recording and reproducing apparatus is configured based on the criterion.

Abstract: The presently disclosed technology teaches a transducer head with a read sensor, a write pole, and one or more waveform sensors attached to the transducer head. Further, a waveform propagates in the direction of a BPM and the waveform sensor is configured to detect the waveform after it is reflected from the BPM. Additionally, a spin-polarized current is influenced by the BPM and a spin angular momentum sensor detects changes in spin angular momentum of the current. Further, a processor relates at least one property of the reflected waveform and/or current with positions of patterned bits on the BPM. The processor may then modify a timing signal and/or transducer head position to ensure that data bits are accurately written to the BPM. The end result is the ability to more quickly and accurately detect the patterned bits and synchronize a position of the transducer head with the patterned bits.

Abstract: The present disclosure includes systems and techniques relating to writing ramp-tracks on a computer readable medium. In some implementations, a trajectory is identified across previously written tracks on a surface of a machine-readable medium for a read-write head to move along and build up velocity. Identifying the trajectory includes identifying one of the previously written tracks as a launch location from which to launch the read-write head. Identifying the trajectory also includes identifying a start writing location near a blank region of the surface of the machine-readable medium at which to turn on a write gate. A current is applied to the read-write head to cause the read-write head to move along the trajectory. In addition, the identified launch location is adjusted until a target velocity is obtained at the start writing location.

Abstract: A signaling method and apparatus for providing two write assist components for perpendicular thin film heads writing to high coercivity media is disclosed. The two components provided by the present invention include a media writing assist component and a head switching assist component. Circuit wiring configurations and waveforms for driving an auxiliary half coil are disclosed. These include configurations for connecting the auxiliary half coil in parallel with the main data coil, or connecting the auxiliary half coil to the thermal flight control system. Provision for both common mode signals as well as differential mode signals are disclosed. RF sinusoidal waveforms between 1 and 5 GHz have been found suitable for head switching assist functions for either symmetric current feed and common mode current configuration, or asymmetric current feed and differential mode current configuration.

Abstract: A magnetic disk apparatus that uses a head to write data in a plurality of unit areas arranged in an adjacent relationship to each other on a surface of a magnetic disk, and includes: a first recording section that records, in a RAM, the position of a unit area which is a target of data write; a first counting section that counts the number of times of data write operation performed for the unit area corresponding to the position recorded by the first recording section; and a second recording section that records, in a non-volatile storage medium different from the RAM, the side position which is the position of a unit area adjacent to the unit area whose number of records counted by the first counting section is more than a predetermined value.

Abstract: Embodiments of the invention broadly contemplate systems, methods and arrangements for managing Adjacent Track Interference (ATI) risk through intelligent management of a table that logs individual tracks creating a risk of ATI in tracks adjacent thereto. Embodiments of the invention provide that tracks considered being at low risk for creating ATI be ejected from the table in order to maintain a track-level log of manageable size.

Abstract: A data storage cartridge comprises data storage media configured to store data for read and/or write access, wherein the data may be arranged in a plurality of partitions; and a plurality of cartridge memories. A control system, for example of a data storage drive, is configured to allocate at least portions of capacity of the data storage media to cartridge memories of the data storage cartridge; and to provide information defining the allocated portions of capacity to the cartridge memories. Each of the cartridge memories may have a separate user and thus provide access for that user to separate partitions.

Abstract: A data storage cartridge comprises data storage media configured to store data for read and/or write access, wherein the data may be arranged in a plurality of partitions; and a plurality of cartridge memories. A control system, for example of a data storage drive, is configured to allocate at least portions of capacity of the data storage media to cartridge memories of the data storage cartridge; and to provide information defining the allocated portions of capacity to the cartridge memories. Each of the cartridge memories may have a separate user and thus provide access for that user to separate partitions.

Abstract: An object of the present invention is to improve safety. A disk array apparatus of the present invention includes: CHE and MEM for temporarily storing data which is transmitted/received between a host device and a disk enclosure; CPU, RAIDC, and NVMC for controlling transmission/reception of data; power supply units for supplying power, which is supplied from an external power supply, to disk array control units; batteries for supplying power to the disk array control unit when the power being supplied from the external power supply is shut OFF without executing power supply shut down processing; an insertion/extraction detection unit for detecting insertion/extraction of a connector used for connecting the disk array control unit with the power supply unit; and battery monitors for stopping power supply by the battery when extraction of the connector is detected while the battery is supplying power to each device of the disk array control unit.

Abstract: Methods and media structures are provided for increasing writability and reducing unintentional erasure of perpendicular magnetic recording media. Variable permeability is controlled within a thin soft underlayer (SUL) structure, independent of bulk SUL material properties such as magnetic moment (Bs) and magnetic anisotropy (Hk). Media with an improved combination of easier writability on the recorded track and difficult erasure off-track (between tracks and on neighboring tracks) is achieved, in part, by an unbalanced antiferromagnetically coupled (AFC) SUL structure. A permeability gradient is established within the soft underlayer with layers having different values of permeability and magnetic thickness (Bs*t). In an aspect, a first SUL layer includes a high permeability region and an overlying low permeability region. A second layer antiferromagnetically couples the first layer to a low permeability third SUL layer.

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: A control method for information processing apparatus includes is provided. The control method includes receiving a lock instruction, locking a library device into a locked state at which insertion, removal and replacement of a medium in the library device is inhibited and/or prevented in response to the lock instruction, generating a map that indicates one or more media in the library device and a position of each of the media, receiving a power-off instruction, and powering off the library device while maintaining the library device in the locked state in response to the power-off instruction.

Abstract: A method and system for providing a personalized entertainment experience that is customized for each user. The history of user control actions (such as “forward” and “back”) associated with each played composition are captured as positive or negative user feedback about each composition. A customized sequence of compositions may be automatically generated for each user by utilizing the prior history of user control actions. The personalized sequence automatically adapts to changing user feedback over time. The user's collection of compositions is automatically integrated with the generated customized sequence. Additional compositions and samples, that are new to a user, may be automatically chosen based on the prior user feedback history and may be added to the user's collection when positive user feedback occurs during playback.

Abstract: In a spindle motor, a capillary seal portion having a radial dimension that decreases in an axially downward direction, and a labyrinth seal portion arranged above the capillary seal portion are defined between an outer circumferential surface of a rotating member and an inner circumferential surface of a tubular portion. The capillary seal portion includes a liquid surface of a lubricating oil positioned therewithin. The radial dimension of the labyrinth seal portion is smaller than the radial dimension of an upper end portion of the capillary seal portion, so that the labyrinth seal portion contributes to reducing evaporation of the lubricating oil.

Abstract: An information storage device includes a record head and a data recording medium. The record head includes a magnetic substance having magnetic domain walls and records data in the data recording medium. In a method of operating the information storage device, a first high frequency current or a high frequency magnetic field is supplied to the magnetic substance while magnetic domain walls of the magnetic substance are moved.

Abstract: A method for writing information on a highly coercive recording medium stably with an electric field applied through a metal probe and with a magnetic field applied from external and an information recording system that employs the method. The recording medium includes a substrate, a first ferromagnetic layer formed on the substrate, a nonmagnetic layer formed on the first ferromagnetic layer, and a second ferromagnetic layer formed on the nonmagnetic layer. The coercivity Hc2 of the second ferromagnetic layer is larger than that Hc1 of the first ferromagnetic layer. A magnetic field H is applied to the magnetic recording medium from a magnetic pole to change the magnetizing direction of the first ferromagnetic layer to a direction of the applied magnetic field, then a positive or negative voltage V is applied between the metal probe and the magnetic recording medium to change the quantum well level energy between the first and second ferromagnetic layers, thereby inducing an exchange magnetic field HE.

Abstract: The magnetic recording and reproducing apparatus includes: a perpendicular recording magnetic recording medium including a track pattern including track portions and gap portions arranged so as to be alternately adjacent to each other in a cross-track direction, at least part of portions corresponding to the track portions being recording areas having the width substantially the same as the width of the track portions, portions between the recording areas being non-recording areas; and a magnetic head of a perpendicular recording type for applying a recording magnetic field to the recording areas. The anisotropic magnetic field Hk (T) of the recording areas of the magnetic recording medium and the recording magnetic field intensity Fw (t) of the recording magnetic field at the upper surface of the recording areas satisfy the following inequality (I): 0.23×Fw+1.2?Hk?0.26×Fw+1.6.

Abstract: A data storage device has a housing having a size and shape compatible with being inserted into a floppy disk drive. A data storage unit is provided within the housing for storing a plurality of floppy disk data images. A rotating hub is mounted in the housing to receive the spindle driven by the floppy disk drive. The rotating hub has a position encoder for generating a hub position signal. A transducer is mounted to the housing spanning a range of motion of the read/write head of the floppy disk drive. A head position sensor is mounted to the housing for generating a head position signal in response to a sensed location of the read/write head. A controller within the housing is responsive to the hub position signal and the head position signal to identify a position within a sector of a selected one of the floppy disk data images and to exchange data between the transducer and the identified position of the selected floppy disk data image in the data storage unit.