Provided is a glass for a magnetic recording medium substrate, which is an amorphous glass, in which an SiO.sub.2 content is in a range of 54 mol % or more and 62 mol % or less, an MgO content is in a range of 15 mol % or more and 28 mol % or less, an Li.sub.2O content is in a range of 0.2 mol % or more, and an Na.sub.2O content is in a range of 5 mol % or less.

In a multi-actuator drive, the effect of moving a first actuator (the so-called “aggressor actuator”) in on a second actuator (the so-called “victim actuator”) is reduced or compensated for. A victim feedforward signal is added to a microactuator control signal of the victim actuator in response to a voice-coil motor (VCM) control signal that is applied to the aggressor actuator. The feedforward signal is configured to compensate for disturbances to the victim microactuator caused by VCM commands provided to the aggressor actuator. The feedforward signal is based on a transfer function that models commands added to the victim microactuator, which is coupled to the head of the victim actuator, as a function of the aggressor VCM control signal applied to the aggressor actuator.

Systems and methods for compensating for magnetoresistive (MR) jog offset direct current (DC) drift in a disc drive are described. In one embodiment, a method may include determining an occurrence of NOS, for example, by monitoring disc slip, to determine when the method should proceed. An MR jog offset DC drift amount is determined for each head of the disc drive. One of several approaches may be employed for determining the MR jog offset DC drift amount. By determining an MR jog offset DC drift amount for each head, a compensation profile is determined for the drive. The determined compensation profile may then be used during operation of the disc drive to compensate for the DC drift. One of several approaches may be employed for compensating based on the compensation profile.

A method for manufacturing a disk device includes the steps of measuring a first gain of a control signal of a fine motion actuator while positioning a head to a first radial position of a disk medium using a coarse motion actuator but not the fine motion actuator, based on an auxiliary servo pattern recorded on the disk medium, measuring a second gain of a control signal of the fine motion actuator while positioning the head to a second radial position of the disk medium using the coarse motion actuator but not the fine motion actuator, based on the auxiliary servo pattern recorded on the disk medium, and determining gain correction values which are to be applied to a control signal for the fine motion actuator while performing servo pattern writing on the disk medium, based on the first and second gains.

An apparatus that includes a read sensor having a bearing surface and first and second free layers that are separated by an intermediate structure. The first FL includes multiple segments, with each segment having a width at the bearing surface. A sum of the widths of different ones of the multiple segments is a first width of the first FL. The second FL is unsegmented and has a second width at the bearing surface that is different from the first width of the first FL. The read sensor also includes a first terminal connected to a first one of the multiple segments of the first FL, and a second terminal connected to a second one of the multiple segments of the first FL. A third terminal is connected to the second FL. Control circuitry applies a bias current from either the first or second terminal to the third terminal.

According to one embodiment, a recording medium controller includes a recording medium, an input module, a reading module, and a writing module. The recording medium includes a write area and an escape area. The write area includes track groups. Each of the track groups is a unit for writing data and includes tracks. The input module receives a write command for data. The reading module reads data stored in the escape area and data from a first track group of the track groups. The writing module writes data received for the write command to the escape area, and writes merged data obtained by merging the data read from the escape area and the data read from the first track group to each track of a second track group of the track groups by using a shingle recording technique in which adjacent tracks are partly overlapped with each other.

A flexure assembly is described. The flexure assembly includes a gimbal portion on configured to receive a slider. The gimbal portion includes a first surface and a second surface which is opposite to the first surface. The slider is mounted on the second surface. The flexure assembly also includes a pair of microactuator elements. The flexure assembly also includes a tongue of the gimbal portion on which the slider is mounted. The tongue includes a dimple point which represents the center of the tongue. The flexure assembly also includes a pair of first supporting portions and a pair of second supporting portions of the gimbal portion. A pair of end portions are individually secured to the tongue and the first supporting portions and the pair of second supporting portions. The flexure assembly also includes a conductive circuit portion unsupported between a first stationary part and the pair of end portions.

A flexure assembly is described. The flexure assembly includes a gimbal portion on configured to receive a slider. The gimbal portion includes a first surface and a second surface which is opposite to the first surface. The slider is mounted on the second surface. The flexure assembly also includes a pair of microactuator elements. The flexure assembly also includes a tongue of the gimbal portion on which the slider is mounted. The tongue includes a dimple point which represents the center of the tongue. The flexure assembly also includes a pair of first supporting portions and a pair of second supporting portions of the gimbal portion. A pair of end portions are individually secured to the tongue and the first supporting portions and the pair of second supporting portions. The flexure assembly also includes a conductive circuit portion unsupported between a first stationary part and the pair of end portions.

According to one embodiment, a method for manufacturing a magnetic disk device includes: moving a magnetic head such that a read head is located on a first learning position among a plurality of learning positions set in a radial direction of a magnetic disk; and learning RRO correction information related to the first learning position using the read head. The method further includes: moving the magnetic head such that the read head is located on a second learning position among the plurality of learning positions; and executing writing of the RRO correction information related to the first learning position using the write head in parallel while learning RRO correction information related to the second learning position using the read head when the read head is located on the second learning position.

A method for writing repeatable run-out data, representing a recurring contribution to position error, to a rotating constant-density magnetic storage medium, includes repeating, for each respective track at a respective radius of the constant-density magnetic storage medium, (1) determining a respective track pattern frequency based on track location and desired data density, (2) locating a position in a respective servo wedge on the respective track based on servo sync mark detection, (3) writing the repeatable run-out data to the respective servo wedge at a time delay, from the location of the position in the respective servo wedge, that is inversely proportional to the respective radius, to achieve a predetermined offset, and (4) repeating the determining, the locating and the writing for each servo wedge on the respective track of the constant-density magnetic storage medium.