Abstract: An acoustic emission sensor is mounted on a flying slider opposed to a rotating recording medium, for example. The acoustic emission sensor outputs a detection signal in response to the sound of collision. When a protrusion exists on the recording medium, the flying slider is expected to collide against the protrusion at a predetermined fixed angular position. A variation is induced in the detection signal based on the collision between the flying slider and the protrusion in synchronization with the rotation of the recording medium. Specifically, when a variation is synchronized with the angular position signal of the recording medium, the variation should correspond to a protrusion existing on the surface of the recording medium. If the component corresponding to the variation is extracted out of the detection signal, a protrusion on the recording medium can be determined at a higher accuracy.

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: A magnetic head is disposed opposite to a magnetic disk having a first recording area capable of facilitating writing information to the magnetic disk when the surrounding temperature is low, and a second recording area capable of surely holding information written to the magnetic disk when the surrounding temperature is high. Information is written to the first recording area when the surrounding temperature is low and is transferred later to the second recording area.

Abstract: The invention relates to a magnetic recording/reproducing device in which a reproduce head is positioned where the crosstalk between adjacent tracks in a magnetic disk is minimized to maintain an adequate transfer rate in a system involving great crosstalk. The removal of crosstalk ensures the reproduction of the recorded data and thus increases the reliability of the magnetic recording/reproducing device. The magnetic recording/reproducing device according to this invention includes a magnetic disk on which a plurality of tracks are concentrically formed, and data are recorded at different frequencies on adjacent tracks.

Abstract: A magnetic recording system, such as a magnetic recording disk drive, uses a patterned perpendicular magnetic recording medium where each magnetic block or island contains a stack of individual magnetic cells to provide multilevel recording. Each cell in an island is formed of a material or set of materials to provide the cell with perpendicular magnetic anisotropy and is a single magnetic domain. Each cell is magnetically decoupled from the other cells in its island by nonmagnetic spacer layers. Thus each cell can have a magnetization (magnetic moment) in one of two directions (into or out of the plane of the layer making up the cell), and this magnetization is independent of the magnetization of the other cells in its island, This permits multiple magnetic levels or states to be recorded in each magnetic island.

Abstract: A method and apparatus for characterization of a thermal response of giant magnetoresistive (GMR) sensors in magnetic read/write heads is provided. The method and apparatus make use of a probe to measure temperatures at a base and a tip of the probe. With the method and apparatus, a temperature of magnetic shields of the read/write head are cooled to a temperature lower than an ambient temperature. A current is then applied to the GMR sensor to increase a temperature of an air bearing surface such that the heat flow through the probe is zero. The amount of current applied, the resistance of the GMR sensor, the magnetic shield temperature, and the ambient temperature are used to calculate a thermal conductance of dielectric material in the read/write head. The thermal conductance is then utilized to estimate the signal to noise ratio of the GMR sensor and determine a maximum bandwidth of the read/write head.

Abstract: A method of determining a transfer speed of an encoded data signal including a clock signal and a data signal is provided. First, the encoded data signal is decoded to generate a decoded clock signal. Then, a data transfer speed of the encoded data signal is determined using the decoded clock signal.

Abstract: A write driver for use with a magnetic recording head includes a photoconductive switch that is positioned adjacent a magnetic recording head for switching current waveforms. Both light and a DC voltage are applied to the photoconductive switch to switch the applied current waveforms. The write driver further includes means for writing to a storage medium in response to current waveforms switched by the photoconductive switch. The write driver may also include a suspension that supports at least one photoconductive switch, DC conductors for supplying a DC voltage, means for supplying light, and recording head means for writing to a storage medium.

Abstract: A method and apparatus for detecting a topographic feature on a media is described. More particularly, a light scatter detector is coupled to an atomic force microscope. The detector is used detect scattered optical energy reflected from the surface of the media to identify the topographic feature. The atomic force microscope may then be positioned in response to the topographic feature identified.

Abstract: The present invention includes a method and apparatus to write and read copy protected data on a disc drive storage system by encoding and decoding data to be copy protected using servo wedge data as the encoding element. In one aspect, the drive is marked by a number generated from the servo wedge data.

Abstract: A magnetic recording apparatus provides improved resolution and S/N without adversely affecting thermal stability. An angle formed by the direction of easy magnetization of a recording layer and the direction normal to a magnetic recording medium is in the range between 5° and 55°, the easy magnetization direction is from a back surface of the recording layer toward a front surface thereof, and when a recording track direction is from the upstream of the direction of transportation of the medium toward the downstream thereof, an angle formed by the direction of a projection of the easy magnetization direction on the medium plane and the recording track direction is in the range between 0° and 70°.

Abstract: A system and method for decoding magnetic media. Parallel decoders, each with a different equalization magnitude, are used to decode a read signal. A Viterbi metric is used to determine the direction and magnitude of equalization shift that best compensates for a systematic separation, such as pole tip recession. If optimal equalization has changed, the equalization coefficients of the decoders is shifted to compensate.

Abstract: A method of designing a thermally-assisted magnetic recording apparatus having a magnetic recording medium, a heater and a magnetic head includes, determining a stable retention time tst for recorded magnetization and a thermal-fluctuation stability coefficient ?st calculated from ?(T)=KuV/kBT, where Ku is a magnetic anisotropy energy density, V is an activation volume, and kB is Boltzmann's constant, obtaining an equivalent degradation time tEQ calculated from tEQ=?(?tEQ), that sums values of ?tEQ within a period of time ?t for a time span during which the medium is substantially degraded, where ?tEQ=exp(ln(?t)????st) and ? is a thermal-fluctuation stability coefficient for a medium temperature T in ?t, and determining specifications of the medium, the heater and the magnetic head in a manner to meet the relationship of tEQ<tst.

Abstract: A disk drive of perpendicular magnetic recording method including a read head comprising a GMR element and a drive using a double-layered disk medium, is disclosed. In the magnetic field response characteristic of the GMR element, the relationship between the degree of nonlinearity and a pulse width at 50% threshold (PW50) of a differentiated read signal is used. The degree of nonlinearity of the GMR element is adjusted such that the PW50 is smaller than the maximum value. The read channel comprises a differentiation circuit for converting the read signal output from the GMR element into the differentiated read signal.

Abstract: A magnetic recording method uses a patterned perpendicular magnetic recording medium where each magnetic block or island contains a stack of individual magnetic cells to providing multilevel recording. Each cell in an island is formed of a material or set of materials to provide the cell with perpendicular magnetic anisotropy and is a single magnetic domain. Each cell is magnetically decoupled from the other cells in its island by nonmagnetic spacer layers. Thus each cell can have a magnetization (magnetic moment) in one of two directions (into or out of the plane of the layer making up the cell), and this magnetization is independent of the magnetization of the other cells in its island. This permits multiple magnetic levels or states to be recorded in each magnetic island.

Abstract: A method for efficiently saving data to tape, preferably within the ANSI X3.27 standard format sends signals to the tape drive to allow the tape drive to buffer the required tape marks, which the standard requires. Although the standard presumed these would be required for synchronization and would be written when produced, we do not adhere to that thinking. Instead we synchronize only at the logical end of the application constructed file, or at the end of the tape in one embodiment, saving time in writing through avoiding stop-start activities of the tape drive, thus allowing newer tape drives to take advantage of the features of the ANSI X3.27 standard. We also provide an embodiment, which allows for non-ANSI standard (i.e., unlabeled) tapes to be used.

Abstract: A method for magnetic recording uses a fixed write current with thermal assistance to record on a patterned perpendicular magnetic recording medium. The patterned medium has magnetic blocks or islands, each of which contains a stack of individual magnetic cells to provide multilevel recording. Each cell in an island is formed of a material or set of materials to provide the cell with perpendicular magnetic anisotropy and is a single magnetic domain. Each cell is magnetically decoupled from the other cells in its island by nonmagnetic spacer layers. Thus each cell can have a magnetization (magnetic moment) in one of two directions (into or out of the plane of the layer making up the cell), and this magnetization is independent of the magnetization of the other cells in its island. This permits multiple magnetic levels or states to be recorded in each magnetic island.

Abstract: A media information distribution and recording system for distributing media information from a central apparatus to terminal apparatus through a network and for recording the media information on a detachable recording medium in the terminal apparatus, wherein the terminal apparatus serves not only as a transmitting terminal apparatus, but also as a receiving terminal apparatus, is proposed, together with the terminal apparatus, a media information recording apparatus for use in this system, and a recording medium which stores a program that controls the operation of a computer for use in this system as well as in the media information recording apparatus.

Abstract: A method of operating a transducer includes heating a write element by passing a preheat electrical current through a conductive coil of the write element in a manner which produces a substantially zero magnetic flux. The method also includes writing data to a media after heating the write element by passing a write electrical current through the conductive coil in a manner in which produces a net magnetic flux.

Abstract: A storage device stores a plurality of information, each having first and second partial information. A reading device reads the first partial information of one arbitrarily selected information to be reproduced, and the corresponding first partial information is reproduced. Also, a reading device reads the second partial information of the arbitrarily selected information during the reproduction of the first partial information.

Abstract: A data tape drive for recording information on the data tape of a tape cartridge has a transducer head with air bleed slots that define side walls, a tape guide, and a device for detecting damage to the transducer head and tape guide. The damage detection device has a conductor loop that is located along the outer edges of the air bleed slots and tape guide for detecting any brittle fracture damage that may be present. The conductor loop is a thin filament of wire that is preferably attached to the ends of the side walls. When the transducer head or tape guide experiences a fracture, such as a fracture in one of the side walls, the delicate filament breaks and forms an open circuit. The open circuit in the conductor loop is detected by the data tape drive so that remedial actions can be taken.

Abstract: A magnetic head is disposed opposite to a magnetic disk having a first recording area capable of facilitating writing information to the magnetic disk when the surrounding temperature is low, and a second recording area capable of surely holding information written to the magnetic disk when the surrounding temperature is high. Information is written to the first recording area when the surrounding temperature is low and is transferred later to the second recording area.

Abstract: A method for forming a magnetic pattern in a magnetic recording medium, which includes irradiating energy beams to a magnetic recording medium having a magnetic layer on a substrate via a photomask having a transmitting portion and a nontransmitting portion to heat locally an irradiated portion of the magnetic layer. The method also includes applying an external magnetic field to the magnetic layer. The transmitting portion and the non-transmitting portion of the photomask each has a reflectivity of energy beam of 30% or less in at least one surface facing the magnetic recording medium. By using techniques of heating a local portion and applying an external magnetic field in combination, a fine magnetic pattern can be effectively and accurately formed while the production of an interference fringe is suppressed.

Abstract: Data for specifying servo bands SB1 to SB5 is embedded in each servo signal S1 to S5 that is written on a plurality of servo bands SB1 to SB5 formed on a magnetic tape MT.

Abstract: The present invention provides a multi-magnetic recording head capable of increasing a magnetic recording density of information recorded on a magnetic recording medium. The multi-magnetic recording head includes a substrate, a pair of first thin film magnetic poles with a specific gap put therebetween, which are stacked over the substrate, and a pair of second thin film magnetic poles with a specific gap put therebetween, which are stacked over the pair of first thin film magnetic poles, wherein the pair of first thin film magnetic poles and the pair of second thin film magnetic poles are offset from each other in the direction nearly perpendicular to the stacking direction.

Abstract: Magnetic tape onto which information may be recorded on either side exhibits the risk of having information recorded on one side affect the opposite side when the two sides are adjacent, such as when the tape is wound in a tape pack. The chance that information recorded onto one surface of a double sided magnetic tape will affect information recorded on the other surface of the magnetic tape is reduced by keeping fields emanating from a recorded region less than about one-half the coercivity of the magnetic medium onto which the information is recorded.

Abstract: In the performance of a magnetic transfer utilizing a magnetic transfer master medium, the occurrence of signal omissions in the magnetic data transferred to the slave medium is prevented. By forming the protrusion portions of the uneven pattern formed on the surface of the master medium so that the width thereof in the direction of the track pitch is narrower than said track width, no depression portions that are surrounded on all four sides by protrusion portions are formed.

Abstract: Provided are a method of magnetic recording and reproducing capable of permitting high density recording on magnetic recording media even under the condition of high data transfer rates and yielding adequate recording and reproduction characteristics when an MR head is used in reproduction, and a magnetic recording medium capable of being used in this magnetic recording and reproducing method. The magnetic recording and reproducing method is a method for reproducing a signal magnetically recorded on a magnetic recording medium with a magnetoresistive (MR) head. The magnetic recording medium comprises a substantially nonmagnetic lower layer and a magnetic layer comprising a hexagonal ferrite ferromagnetic powder and a binder in this order on at least one side of a nonmagnetic support, in which said hexagonal ferrite ferromagnetic powder has a mean plate diameter ranging from 15 to 40 nm and a mean plate thickness ranging from 4 to 15 nm, and said magnetic layer has a coercive force Hc ranging from 143.

Abstract: A disk drive having a connection-blocking device for use with a Serial Advanced Technology Attachment (SATA) power receptacle. The disk drive has a moveable head for writing and reading to and from a disk, a printed circuit board assembly (PCBA) for controlling operations in the disk drive, a Serial Advanced Technology Attachment (SATA) section attached to the PCBA having a SATA power receptacle and a SATA data receptacle, a legacy Integrated Drive Electronics (IDE) power receptacle attached to the PCBA, and a connection-blocking device. The legacy IDE power receptacle is electrically common with the SATA power receptacle. The connection-blocking device is attachable to either one of the SATA power receptacle or the legacy IDE power receptacle, respectively, to prevent redundant power connections within the disk drive.

Abstract: A PLL circuit is disclosed which extracts phase difference information of a high S/N ratio from a readout signal uses the phase difference information for PLL control. An A/D converter samples the input signal to produce a digital signal. A pattern string detector identifies a type of an input pattern string formed from a plurality of successive sample values successively outputted from the A/D converter and outputs pattern string identification information which indicates an identification result. A phase difference generator outputs phase difference information which indicates a phase error of the output of the A/D converter based on the pattern string identification information and the output of the A/D converter. A loop filter, a D/A converter and a voltage controlled oscillator generate a clock signal from the phase difference information to control the sampling timing of the A/D converter.

Abstract: A method includes providing a superconducting material having pinning sites that can pin magnetic vortices within the superconducting material. The method also includes pinning one or more magnetic vortices at one or more of the pinning sites. An information storage apparatus includes a superconducting material, doped particles within the superconducting material that can pin dipole magnetic vortices, a magnetic tip that generates pinned magnetic vortices and a magnetic detector that detects pinned magnetic vortices.

Abstract: A magnetic recording head comprises a write pole having a tip adjacent to an air bearing surface of the recording head, a return pole magnetically coupled to the write pole, a conductor positioned adjacent to at least one edge of the write pole at the air bearing surface for carrying current to produce a magnetic field that saturates at least a portion of the write pole and augments a write field, a first conductive heat sink connected to a first end of the conductor, and a second conductive heat sink connected to a second end of the conductor. Disc drives that include the recording head are also included.

Abstract: A head suspension assembly having a magnetic head, an arm which is supported so as to rotate, a suspension having one end which is fixed to an end of the arm and an other end which mounts the magnetic head, a nonvolatile memory which is mounted on the suspension assembly, and stores control parameters of the magnetic head, a connecting terminal which is mounted to the arm, and a signal transmission line which electrically connects the connecting terminal to the nonvolatile memory and the magnetic head. The connecting terminal enables transmission of signals at least one of to and from the head suspension assembly, the nonvolatile memory and the magnetic head.

Abstract: A playback error associated with overwriting on a narrow-width track is prevented from occurring in the overwritten portion. A signal generator (11) generates a signal of a predetermined data pattern that stabilizes the operation of a synchronizing pulse generator of a playback system (shown in a separate figure). A timing generator (4) switches over a switch (12) to the output of the signal generator (11), at least a period of time equivalent to writing of one track before the main signal is input. When a signal of the predetermined data pattern from the signal generator (11) has been output, the timing generator (4) switches over the switch (12) to the main signal. The playback system includes a circuit which discriminates between the predetermined data pattern and the main signal data from a playback signal generated by playing back a record on a magnetic tape (T).

Abstract: As a tape recording format, tracks are formed by a succession of block units, and a data unit called a group is formed by data of size equivalent to a predetermined plurality of tracks. Using this format, a base group number indicating the group to which the current track physically belongs is recorded in the ID information for a track, and the lower four bits or similar of a group number indicating the group to which the current block logically belongs is recorded within a block. By this means, even if rewriting is performed in block units and a recorded state results in which the blocks of a plurality of groups are intermixed within a track, the group to which each block belongs can be correctly identified during reproduction.

Abstract: A disc drive includes a base and a disc rotatably attached to the base. The disc drive also includes an actuator assembly rotatably attached to the base and a device for moving the actuator assembly. The actuator assembly includes an arm carrying a transducer head in a transducing relationship with respect to the disc. The disc drive further includes a servo circuitry and a controller for controlling movement of the actuator assembly during a track follow and a track seek. Piezoelectric transducers are attached to the actuator assembly for non-intrusive measurement of stiction and friction forces developed between the transducer head and the disc during a disc drive spin-up.

Abstract: When jitter-like noise is prominent, sampling-phase control and amplitude control in a preamble pattern region is affected. It is possible to reduce effects of jitter-like noise without increasing the length of the preamble pattern. By altering a preamble pattern from that of a conventional 4T-cycle to 6T-cycle or over, amplitude data at a peak point of a reproduced signal, which is less affected by jitter-like noise, is utilized. Thus, the stability of the amplitude control can be improved. As to the phase control, a shift of the sampling timing is estimated by sample data of one cycle of the preamble pattern, and an acquisition procedure of the timing control is made faster.

Abstract: The present invention relates to an improved structure of a multi-purpose thumb-like hard disk device especially one very small and easy to carry along. The present invention mainly consists of a digital music playing module, a battery stand and a laser source assembled in a thumb-like shell designed with recording, playing, information transmission and laser operating buttons as well as indicating lights for operation of different functions. The present invention therefore provides a very convenient small sized MP3, recorder, laser pen drive and surface file transmission device.

Abstract: A magnetic recording medium for recording information by forming a magnetic pattern for information thereon by a magnetic head, which is a longitudinal magnetic recording medium having a coercive force of at least 3000 Oe, and which has a magnetic pattern for control of the magnetic head preliminarily formed thereon, wherein the full width at half maximum of an isolated pulse of a reproducing signal of the magnetic pattern for control is smaller than the full width at half maximum of an isolated pulse of a reproducing signal of the magnetic pattern for information.

Abstract: A scanner (3-85, 8-85, 9-85) for use in a helical scan magnetic transducing apparatus has a periphery upon which plural read tranducing elements (3-82) and plural write transducing elements (3-80) are mounted non-symmetrically. The plural write transducing elements are physically situated on the periphery of the scanner in M number of local groups (3-81), wherein the plural read transducing elements are physically situated on the periphery of the scanner in N number of local moveable groups (3-831, 3-832), and wherein M<N. Each of the moveable groups has a separate actuator (89) for adjusting position of the group.

Abstract: A circuit includes a buffer for receiving and storing two samples of a signal, and a phase calculation circuit for calculating from the samples a phase difference between one of the samples and a predetermined point of the signal. Such a circuit can be used to decrease the alignment-acquisition time of a digital timing-recovery loop, and thus allows a shortening of the sector preambles and a corresponding increase in the data-storage density of a disk. In one application, the circuit determines an initial phase difference between a disk-drive read signal and a read-signal sample clock. The digital timing-recovery loop uses this phase difference to provide an initial coarse alignment between the read signal and the sample clock. By providing an initial coarse alignment, the recovery loop reduces the overall alignment-acquisition time.

Abstract: A digital VFO phase control device comprising: an output signal generation means for generating an output signal having the predetermined phase relationship with an input signal of the digital VFO phase control device, a phase difference detection means for detecting a phase difference between the input signal and the output signal, a first correction value output means for outputting a correction value for correcting a phase of the output signal based on a phase difference detected by the phase difference detection means, a second correction value output means for outputting a preset correction value for correcting a phase of the output signal based on a phase difference detected by the phase difference detection means, a comparison means for detecting whether or not the phase difference detected by the phase difference detection means being within a predetermined range, and a correct value selection means for selecting either one of a correction value outputted by the first correction value output means and

Abstract: An apparatus and method for adding errors to magnetic data and then detecting the errors is revealed. The method includes providing a magnetic recording channel, reading and digitizing a stored signal, introducing an error signal that emulates off-track interference, adding the error to the digitized signal, and determining an error rate. The apparatus includes a magnetic recording channel having a linear feedback shift register to generate a pseudo-random binary sequence, circuitry to convert the sequence into an error signal, and a Viterbi detector to quantify an error rate.

Abstract: A service system is provided for recording spoken passages exchanged between parties, for example, via the public telephone system. The service system is called into action preferably by the agreement of the parties and is used to make a recording of the spoken exchanges between the parties. At the termination of recording, each party is preferably provided with the opportunity to review the recording and asked to confirm their acceptance of the recording. The service system then provides a reference copy of the recording. Where a digital copy of the recording is made, the parties are preferably required to indicate their acceptance by digitally signing and returning the recording to the service system.

Abstract: A method for detecting the degree of wear of a magneto-resistance (MR) effect type magnetic head element for reading a magnetic signal by use of a simple structure is disclosed. The degree of wear of an MR head for reading a magnetic signal from a magnetic tape is detected based on a value of resistance of an MR element by a head wear detecting circuit. A signal indicative of the degree of wear of the MR head is supplied to an alarm generating circuit for example, to generate an alarm informing of the life of the MR head.

Abstract: In magnetic transfer performed to transfer an information signal such as a servo signal from a master medium to a slave medium, the degradation of transfer quality caused by a failure of close contact between the master medium and the slave medium due to dust accumulated thereon is prevented. Magnetic transfer means is provided to carry out the magnetic transfer by bringing the master medium bearing information and the slave medium into close contact with each other, and applying a transfer magnetic field. Replacing means is provided to prepare a plurality of master media, and replacing the master medium after magnetic transfer is performed a predetermined number of times. Cleaning means is also provided to clean the replaced master medium by ultrasonic washing or the like.

Abstract: Magnetic data storage media having recording layers that include microscopic surface protrusions are described. A recording head of a magnetic drive may contact the protrusions, i.e., the protrusion tops may define a load bearing surface area of the recording layers of such media. The heights of the protrusions under the recording head and distribution of the protrusions on the recording layers of such media may be substantially uniform. The load bearing surface area may be relatively small when compared to the total surface areas of the recording layers of such media. Also, the average distance between any two adjacent protrusions on such media may be defined based on the length of bits recorded thereon.

Abstract: A magnetic recording disk drive having an interline crosstalk amplitude detection unit 36 within its preamplifier 20 is provided. The detection unit 36 is used for detection coil malfunctions. The interline crosstalk amplitude detection unit 36 includes an interline crosstalk amplitude detection circuit 31 which is branched from a branch circuit 30 within the read circuit in the preamplifier 20. The interline crosstalk amplitude detection unit 36 is provided with the capability to determine occurrence of a write condition abnormality when the amplitude has exceeded a threshold value, making it possible to ensure the recording function of the preamplifier 20. Likewise, the inductance is reduced when a circulatory shunt has occurred in a line near the head, making it possible to detect a write condition abnormality.

Abstract: The maximum external magnetic field of a magnetic recording medium longitudinal component which is applied to a magnetic recording medium is smaller than an absolute value Hn of a magnetic field at the intersection of a straight line connecting two points of an M-H curve in the longitudinal direction of a soft magnetic backing layer and a tangent of the M-H curve. One of the two points is a point (Hs, Ms) at which magnetization saturates in the first quadrant. The other of the two points is a positive intersection (0, Mr) of the M-H curve and the ordinate. The tangent is at a negative intersection (−Hc, 0) of the M-H curve and the abscissa.

Abstract: A magnetic recording and/or reproducing apparatus performing efficient decoding to lower a decoding error rate. A magnetic recording and/or reproducing apparatus 50 includes a modulation SISO decoder 63 for modulation decoding data modulation-encoded in a predetermined fashion by a modulation coder 52. In the magnetic recording and/or reproducing apparatus 50, the modulation SISO decoder 63 is a soft input soft output (SISO) type modulation decoder fed with a soft input signal and issuing a soft output signal. The modulation SISO decoder 63 is fed with a trellis soft output signal D64 supplied from a trellis SISO decoder 62 to find a soft decision value for an error correction coding data D52 fed to the modulation coder 52 of the recording system to generate a modulated soft decision signal D65. The modulation SISO decoder 63 routes the so-generated modulated soft decision signal D65 to a downstream side error correction soft decoder 64.