G11B5/03

Direct measurement of magnetoresistive head resistance in a storage system

A computer program product, system, and method are provided for direct resistance measurement of a magnetoresistive (MR) head of a storage drive in a storage system. In one embodiment, a voltage difference across the MR reader head is measured directly by applying an AC current to the MR head to generate an AC voltage across the MR head that can propagate through filter capacitors and be measured. In one embodiment, the voltage difference is amplified and the peak-to-peak voltage at the output of the amplifier is captured. Similarly, a reference voltage difference across a reference resistance is measured directly by applying a reference AC current to a reference resistance. The resistance of an MR reader head may be calculated directly as a function of the respective voltage differences without including the resistance of any bias resistors biasing the MR head.

Direct measurement of magnetoresistive head resistance in a storage system

A computer program product, system, and method are provided for direct resistance measurement of a magnetoresistive (MR) head of a storage drive in a storage system. In one embodiment, a voltage difference across the MR reader head is measured directly by applying an AC current to the MR head to generate an AC voltage across the MR head that can propagate through filter capacitors and be measured. In one embodiment, the voltage difference is amplified and the peak-to-peak voltage at the output of the amplifier is captured. Similarly, a reference voltage difference across a reference resistance is measured directly by applying a reference AC current to a reference resistance. The resistance of an MR reader head may be calculated directly as a function of the respective voltage differences without including the resistance of any bias resistors biasing the MR head.

ENERGY-ASSISTED MAGNETIC RECORDING DATA STORAGE DEVICE WITH OPPORTUNISTIC BOOSTED LASER PRE-BIASING
20240221779 · 2024-07-04 ·

Various illustrative aspects are directed to a data storage device, comprising one or more disks; an actuator mechanism configured to position one or more heads proximate to a corresponding disk surface of the one or more disks; and one or more processing devices. The selected head comprises a write element and an assistive energy emitter. The one or more processing devices are configured to apply an assistive energy current to the assistive energy emitter while refraining from applying a write current to the write element.

ENERGY-ASSISTED MAGNETIC RECORDING DATA STORAGE DEVICE WITH OPPORTUNISTIC BOOSTED LASER PRE-BIASING
20240221779 · 2024-07-04 ·

Various illustrative aspects are directed to a data storage device, comprising one or more disks; an actuator mechanism configured to position one or more heads proximate to a corresponding disk surface of the one or more disks; and one or more processing devices. The selected head comprises a write element and an assistive energy emitter. The one or more processing devices are configured to apply an assistive energy current to the assistive energy emitter while refraining from applying a write current to the write element.

Data storage device with enhanced management of laser pre-bias and logic block addressing in heat-assisted magnetic recording

Various illustrative aspects are directed to a data storage device, comprising one or more disks; an actuator mechanism configured to position one or more heads proximate to a corresponding disk surface of the one or more disks; and one or more processing devices. The one or more processing devices are configured to: select a sector on the corresponding disk surface to which to write data, wherein the sector is selected in accordance with a data erosion mitigation pattern; and output, while the head is positioned proximate to a preceding sector that precedes the selected sector, a laser pre-bias current to a laser-generating component of the head, wherein the laser pre-bias current is sufficient to induce significant data erosion on the preceding sector.

Data storage device with laser pre-bias optimization using disk thermal-magnetic response mapping in heat-assisted magnetic recording

Various illustrative aspects are directed to a data storage device, comprising one or more disks; an actuator mechanism configured to position one or more heads proximate to a corresponding disk surface of the one or more disks; and one or more processing devices. The one or more processing devices are configured to generate a determination of magnetic responsiveness to thermal energy of at least one position of the corresponding disk surface in response to an operation of the selected head. The one or more processing devices are further configured to determine and apply a pre-bias current to the thermally energizing component prior to a write operation, with the selected head proximate to the at least one position of the corresponding disk surface, wherein the pre-bias current is based on the determination of magnetic responsiveness to thermal energy of the at least one position of the corresponding disk surface.

Data storage device with laser pre-bias optimization using disk thermal-magnetic response mapping in heat-assisted magnetic recording

Various illustrative aspects are directed to a data storage device, comprising one or more disks; an actuator mechanism configured to position one or more heads proximate to a corresponding disk surface of the one or more disks; and one or more processing devices. The one or more processing devices are configured to generate a determination of magnetic responsiveness to thermal energy of at least one position of the corresponding disk surface in response to an operation of the selected head. The one or more processing devices are further configured to determine and apply a pre-bias current to the thermally energizing component prior to a write operation, with the selected head proximate to the at least one position of the corresponding disk surface, wherein the pre-bias current is based on the determination of magnetic responsiveness to thermal energy of the at least one position of the corresponding disk surface.

MANAGING LASER DIODE CAVITY THERMAL TRANSIENTS IN HAMR DISK DRIVES
20240332893 · 2024-10-03 ·

A data storage device may include one or more disks, an actuator arm assembly comprising one or more magnetic recording heads, a laser diode positioned inside a laser diode cavity, and one or more processing devices configured to initiate a write operation, wherein initiating the write operation comprises activating a magnetic recording head corresponding to the laser diode, and applying a forward bias to the laser diode; apply a first reverse bias to the laser diode during at least one intervening event; and transition from applying the first reverse bias to the at least one laser diode to applying the forward bias to the at least one laser diode.

MANAGING LASER DIODE CAVITY THERMAL TRANSIENTS IN HAMR DISK DRIVES
20240332893 · 2024-10-03 ·

A data storage device may include one or more disks, an actuator arm assembly comprising one or more magnetic recording heads, a laser diode positioned inside a laser diode cavity, and one or more processing devices configured to initiate a write operation, wherein initiating the write operation comprises activating a magnetic recording head corresponding to the laser diode, and applying a forward bias to the laser diode; apply a first reverse bias to the laser diode during at least one intervening event; and transition from applying the first reverse bias to the at least one laser diode to applying the forward bias to the at least one laser diode.

Preheating laser diodes with reverse bias for HAMR disk drives

A data storage device may include one or more disks, an actuator arm assembly comprising one or more disk heads, at least one laser diode positioned inside a corresponding laser diode cavity, a preamplifier, and one or more processing devices. The one or more processing devices are configured to: generate a reverse bias; apply, using the preamplifier, the reverse bias to the at least one laser diode to preheat a corresponding laser diode cavity to a target temperature prior to a write operation; control transition of the preamplifier from applying the reverse bias to applying a forward bias to the at least one laser diode; and activate the at least one laser diode to begin the write operation.