HGST (WD) Assigned Five Patents

Shingled magnetic recording HDD with minimization of effect
of far track erasure on adjacent data bands
HGST Netherlands, Amsterdam, The Netherlands, has been assigned a patent (8,537,481) developed by six co-inventors for a “shingled magnetic recording disk drive with minimization of the effect of far track erasure on adjacent data bands.”

The co-inventors are Zvonimir Z. Bandic, Cyril Guyot, San Jose, CA, Tomohiro Harayama, Sunnyvale, CA, Robert Eugeniu Mateescu, San Jose, CA, Shad Henry Thorstenson, Rochester, MN, and Timothy Kohchih Tsai, Alviso, CA.

The abstract of the patent published by the U.S. Patent and Trademark Office states: “A shingled magnetic recording HDD  essentially eliminates the effect of far track erasure (FTE) in the boundary regions of annular data bands caused by writing in the boundary regions of adjacent annular data bands. The extent of the FTE effect is determined for each track within a range of tracks of the track being written. Based on the relative FTE effect for all the tracks in the range, a count increment (CI) table or a cumulative count increment (CCI) table is maintained for all the tracks in the range. For every writing to a track in a boundary region, a count for each track in an adjacent boundary region, or a cumulative count for the adjacent boundary region, is increased. When the count reaches a predetermined threshold the data is read from that band and rewritten to the same band.”

The patent application was filed on March 17, 2012 (13/423,177).

Channel-source laser-pulsing system architecture
for thermal-assisted recording
HGST Netherlands, Amsterdam, The Netherlands, has been assigned a patent (8,503,125) developed by four co-inventors for a “channel-source laser-pulsing system architecture for thermal-assisted recording.”

The co-inventors are John Contreras, Palo Alto, CA, Weldon Hanson, Rochester, MN, Barry C. Stipe, San Jose, CA, and Rehan Zakai, San Ramon, CA

The abstract of the patent published by the U.S. Patent and Trademark Office states: “A method and apparatus for generating a laser signal for driving a laser used in thermal-assisted recording. A channel of a HDD generates a high-frequency component of the laser signal – e.g., a periodic wave or series of pulses–and synchronizes the phase of the laser signal with a corresponding write data signal which controls the magnetization of data bits within the magnetic disk of the HDD. The channel may be connected to a R/W integrated circuit via a channel interconnect. The R/W circuit may include a second phase control to compensate for any phase shift and an adder circuit to combine the transmitted high-frequency laser with a DC bias. Further, the R/W circuit may include a feedback loop for adjusting the DC bias based on environmental parameters of the HDD such as temperature.”

The patent application was filed on May 27, 2011 (13/117,300).

Use of magnetic material for RIE stop layer
during damascene main pole formation
HGST Netherlands, Amsterdam, The Netherlands, has been assigned a patent (8,508,886) developed by six co-inventors for the “use of magnetic material for RIE stop layer during damascene main pole formation.”

The co-inventors are Yingjian Chen, Shiwen Huang, Fremont, CA, Edward Hin Pong Lee, Mun Hyoun Park, San Jose, CA, Kyusik Shin, Pleasanton, CA, and Yuming Zhou, Lakeville, MN.

The abstract of the patent published by the U.S. Patent and Trademark Office states: “A write head for use in a magnetic disk drive and methods of manufacturing the same. When a non-magnetic reactive ion etching (RIE) stop layer is used in a damascene main pole fabrication process, the leading edge shield and the side shield have a magnetic separation. By replacing a non-magnetic RIE stop layer with a magnetic RIE stop layer, no removal of the RIE stop layer around the main pole is necessary. Additionally, the leading edge shield and the side shield will magnetically join together without extra processing as there will be no magnetic separation between the leading edge shield and the side shield.”

The patent application was filed on Sept. 28, 2011 (13/247,883).

HDD with variable incremented counting of writes to data tracks
for minimizing effect of far track erasure
HGST Netherlands, Amsterdam, The Netherlands, has been assigned a patent (8,531,793) developed by Zvonimir Z. Bandic, San Jose, CA, Marco Sanvido, Belmont, CA, and Bruce Alexander Wilson, San Jose, CA, for a “disk drive with variable incremented counting of writes to the data tracks for minimizing the effect of far track erasure.”

The abstract of the patent published by the U.S. Patent and Trademark Office states: “A HDD minimizes the effects of far track erasure (FTE) by counting the number of writes to the data tracks and incrementing counters based on the known effect of FTE on each track. The extent of the FTE effect is determined for each track within a range of tracks of the track being written, and based on the relative FTE effect for all the tracks in the range a count increment (CI) is determined for each track within the range. A counter is maintained for each track. For every writing to a track, a count for each track within a range of the track being written is increased by the CI value associated with the track number within the range. When the count value for a track reaches a predetermined threshold the data is read from that track and rewritten, preferably to the same track.”

The patent application was filed on July 19, 2010 (12/839,391).

Storage devices accepting queued commands having deadlines
HGST Netherlands, Amsterdam, The Netherlands, has been assigned a patent (8,539,176) developed by six co-inventors for “storage devices accepting queued commands having deadlines.”

The co-inventors are Donald Joseph Molaro, Cupertino, CA, Frank Rui-Feng Chu, Milpitas, CA, Jorge Campello de Souza, Cupertino, CA, Atsushi Kanamaru, Sagamihara, Japan, Tadahisa Kawa, Suita, Japan, and Damien C.D. Le Moal, Machida, Japan.

The abstract of the patent published by the U.S. Patent and Trademark Office states: “A storage device accepts queued read and write commands that have deadlines. The queued read and write commands are requests to access the storage device. The deadlines of the queued read and write commands can be advisory deadlines or mandatory deadlines.”

The patent application was filed on July 8, 2008 (12/169,507).