According to one embodiment, a method for evaluating a magnetic head is disclosed. The method can include measuring an electrical characteristic of a current path when an alternating-current magnetic field is applied to the magnetic head. The magnetic head includes the current path. The current path includes an oscillator. The method can include, based on the electrical characteristic, deriving a frequency value relating to an oscillation frequency of the oscillator.

A wiring circuit board includes an insulating layer and a conductive layer disposed on a front surface of the insulating layer. The conductive layer includes a first wiring, a first terminal electrically connected to the first wiring, a second wiring independent of the first wiring and having a thick thickness T2 with respect to a thickness T1 of the first wiring, and a second terminal electrically connected to the second wiring. The surfaces of the first terminal and the second terminal are disposed at generally the same position in a thickness direction.

According to one embodiment, a magnetic recording/reproducing device includes a plurality of magnetic recording medium each including a recording surface, a plurality of assisted magnetic recording heads each provided with the recording surface in order to perform assisted recording, and an assisting amount adjustment part connected to the assisted magnetic recording heads in order to adjust an assisting amount of each assisted magnetic recording head corresponding to a recording capacity of the recording surface.

A system is provided to receive a first request to write data to a hard disk drive (HDD) which comprises a plurality of tracks which can be configured as a conventional magnetic recording (CMR) media or as a shingled magnetic recording (SMR) media, wherein an SMR-configured track stores a greater amount of data than a CMR-configured track. The system writes the data to a first CMR-configured track, and classifies data stored in CMR-configured tracks as hot or cold based on a first or a second predetermined threshold. The system copies cold data from the CMR-configured tracks to an SMR zone, and makes available portions of the CMR-configured tracks previously occupied by the cold data.

Aspects of the present disclosure generally relate to a magnetic recording head assembly that includes an external alternating current (AC) source. A magnetic recording head of the magnetic recording head assembly includes a conductive structure between a main pole and a trailing shield. The conductive structure includes a conductive layer, and the conductive layer is nonmagnetic. The magnetic recording head assembly also includes an external AC source to supply AC current that flows through the conductive structure. In one aspect, the conductive structure is between a coil structure and the trailing shield, and the external AC source is coupled to the coil structure. The conductive structure and the external AC source facilitate consistently providing an enhanced AC writing field to facilitate effective and reliable writing, high ADC, high SNR, and reduced jitter.

A physical unclonable function (PUF) apparatus having magnetic particles is disclosed. The magnetic field data and the image view of the magnetic particles in the PUF apparatus are difficult to counterfeit. A PUF apparatus may be incorporated into a user-replaceable supply item for an imaging device. Further, a PUF reader may be incorporated into an imaging device to read the PUF. Other systems are disclosed.

A physical unclonable function (PUF) apparatus having magnetic particles is disclosed. The magnetic field data and the image view of the magnetic particles in the PUF apparatus are difficult to counterfeit. A PUF apparatus may be incorporated into a user-replaceable supply item for an imaging device. Further, a PUF reader may be incorporated into an imaging device to read the PUF. Other systems are disclosed.

A method for scheduling data transfer commands between a first actuator or a second actuator across an interface is disclosed. The method includes balancing data transfer commands between the first actuator and the second actuator by applying a first rule for read commands and a second rule for write commands.

A storage control apparatus is configured to access a physical storage region of a storage apparatus corresponding to a logical address of a logical storage region, when an error is detected, specify a physical address of the physical storage region, for each of a plurality of regions generated by dividing the physical storage region using a plurality of division conditions different from each other, specify a number of times in which the error is detected, specify a recovery target region in which the number of times is equal to or greater than a first value, specify a first division condition generating the recovery target region, select, from a plurality of recovery methods, a first recovery method corresponding to the first division condition, and cause the storage apparatus to recover a first logical address in the logical storage region corresponding to the recovery target region by using the first recovery method.

A storage control apparatus is configured to access a physical storage region of a storage apparatus corresponding to a logical address of a logical storage region, when an error is detected, specify a physical address of the physical storage region, for each of a plurality of regions generated by dividing the physical storage region using a plurality of division conditions different from each other, specify a number of times in which the error is detected, specify a recovery target region in which the number of times is equal to or greater than a first value, specify a first division condition generating the recovery target region, select, from a plurality of recovery methods, a first recovery method corresponding to the first division condition, and cause the storage apparatus to recover a first logical address in the logical storage region corresponding to the recovery target region by using the first recovery method.