Hgst Netherlands, B.v.

Samsung Electronics Co., Ltd.

Craig K Yanagisawa

John Thomas Contreras

Joey Martin Poss

Bernd Lamberts

Remmelt Pit

Nobumasa Nishiyama

Karl Arthur Flechsig

Samir Y Garzon

Saurabh Deoras

Tuyen Van Trinh

Yasunori Kubo

Managing the flying height of a read-write head slider, such as in the context of a short or head switch seek, involves pre-heating the switched-to head while the active head is still performing a data read or write operation. Thus, both the active head and the switched-to head may be heated simultaneously, and once the switched-to head is switched to an active state upon the active head completing its corresponding operation, the switched-to head can immediately begin its operation with minimal or no further delay.

Preheating a hard disk drive head slider for head switch seek

A disk drive has multiple preamplifiers (preamps) connected to the system-on-a-chip (SOC) by a common transmission line with resistors between the preamps and the SOC. Each preamp includes a read resistor at the output of each read amplifier, and a write resistor at the input of each write driver. The resistors may be programmable resistors located in the preamps. The read resistors are at the source of the signal to the transmission line and the write resistors are at the termination of the signal from the transmission line. The read and write resistors provide impendence matching with the transmission line and the SOC when one of the preamps is selected as active, which enables the SOC to operate seamlessly with a common transmission line connected to all preamps.

Magnetic recording disk drive with multiple preamplifiers and common transmission line with impedance compensation

A method, apparatus, and system for implementing calibration of cooling sensitivity of embedded contact sensor (ECS) using thermal fly-height control (TFC) actuations, by subtracting the linear part (TFC heat) from the total measured ECS signal, a profile is provided that is sensitive only to the clearance of the head-disk interface due to cooling effect for hard disk drives.

Implementing calibration of cooling sensitivity of embedded contact sensor (ECS) signal using thermal fly-height control (TFC) actuations

The invention is a disk drive with a thermal fly-height actuator and a fly-height controller that compensates for exponential write pole protrusion during a write operation. The fly-height controller includes fly-height control logic that controls a single digital-to-analog converter (DAC) that outputs a voltage to drive the heater. Prior to writing, the heater is at the heater power value (HPV) required to maintain the read head at the desired fly-height (Read-HPV). At the initiation of writing the fly-height control logic inputs a new HPV to the DAC to reduce the heater power to begin the compensation. A new and successively reduced HPV is input to the DAC for each servo-identification (SID) mark, during which writing is prevented. When the DAC output voltage approaches the voltage corresponding to the desired write-head fly-height, the method is done.

Disk drive with head thermal fly-height actuator and controller for compensation of write head expansion

A hard disk drive that stores data on a disk. An overshoot duration is used to write data onto the disk. The value of the overshoot duration is a function of the data rate, which can vary for different areas of the disk. For example, the data rate can be higher at an outer diameter of the disk than at an inner disk diameter. The overshoot duration can therefore be different when writing data at the outer diameter than the duration used to write data at the inner diameter. The data rate can be determined by analyzing a preamble of the data written onto the disk.

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Palo Alto, CA, United States of America

Craig K Yanagisawa