HGST (now WD) Assigned Three Patents

PMR system with spin torque oscillator and control circuitry
for fast switching of write pole magnetization

Hitachi Global Storage Technologies, Inc., Amsterdam, The Netherlands, has been assigned a patent (8,351,155) developed by John Thomas Contreras, Palo Alto, CA, and Manfred Ernst Schabes, Saratoga, CA, for a "perpendicular magnetic recording system with spin torque oscillator and control circuitry for fast switching of write pole magnetization."

The abstract of the patent published by the U.S. Patent and Trademark Office states: "A perpendicular magnetic recording hard disk drive includes a write head with a write pole and an electrically conductive coil coupled to the write pole, a write driver for supplying electrical write current to the coil to generate magnetic flux in the write pole, a spin torque oscillator (STO) that injects auxiliary magnetic flux to the write pole to facilitate magnetization switching of the write pole, and STO control circuitry. Direct electrical current to the STO induces rotation of the magnetization of a free ferromagnetic layer in the STO, which generates the auxiliary magnetic flux. The STO control circuitry may be coupled to the STO via the electrical lines that connect the write driver to the write head, the lines that connect the read amplifier to the read head, or, if the disk drive is one with thermal fly-height control (TFC), the lines that connect the TFC circuitry with the heater."

The patent application was filed on Aug. 17, 2009 (12/542,682).

Air pump in HDD

Hitachi Global Storage Technologies, Inc., Amsterdam, The Netherlands, has been assigned a patent (8,345,378) developed by Ferdinand Hendriks, Morgan Hill, Canada, for an "air pump in a HDD."

The abstract of the patent published by the U.S. Patent and Trademark Office states: "An air pump for generating air pressure in a HDD including a rotor disposed inside the HDD. The rotor comprises a first air pressure generating feature. The air pump further includes a stator. The stator includes a second air pressure generating feature. The first air pressure generating feature corresponds with the second air pressure generating feature and the air pressure is generated at a location where the first air pressure generating feature rotates in proximity to the second air pressure generating feature."

The patent application was filed on Dec. 29, 2005 (12/649,097).

Implementing enhanced host to physical storage mapping
using numerical compositions for persistent media

Hitachi Global Storage Technologies, Inc., Amsterdam, The Netherlands, has been assigned a patent (8,352,707) developed by David Robison Hall, Rochester, MN, for "implementing enhanced host to physical storage mapping using numerical compositions for persistent media."

The abstract of the patent published by the U.S. Patent and Trademark Office states: "A method and a storage system are provided for implementing host logical address to physical memory address mapping for persistent storage media including flash memory. Numerical compositions at multiple levels of granularity are used to store the logical address to physical memory address mappings. A plurality of groupings, each grouping including a fixed number of blocks is encoded using recursive composition, eliminating the need to store separate lengths."

The patent application was filed on June 10, 2010 (12/797,683).