Meet the Fellows

We have a broad range of technical disciplines on our R&D team that include aeronautics, applied physics, chemistry, computer science, electrical engineering, material science, mathematics, mechanical engineering, and physics. We work on a broad range of activities from basic research projects on fundamental materials and devices to the very practical engineering and testing of our products. Our scientists and engineers are well known in the industry for their innovations and contributions, and we don’t hesitate to recognize them.

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Tom Albrecht

is a versatile and creative physicist who has combined cutting-edge research with imaginative mechanical insights spanning a wide range of topics and disciplines while helping create a number of iconic data-storage devices and technologies.

Albrecht currently heads the HGST research team developing bit-patterned media, an ultra-high-data-density technology that the data-storage industry recognizes as potentially transformative but monumentally difficult to make in a cost-effective way. Under Albrecht’s leadership since 2004, the group has made tremendous progress and has developed key aspects of several new, contributing technologies, including rotary-stage e-beam lithography, directed self-assembly of block copolymers, line doubling and UV-cure nanoimprint lithography.

A native of Sparta, Wisc., Albrecht was educated at Carleton College (B.A., Physics, 1985) and Stanford University (Ph.D. Applied Physics, 1989).

After graduation, Albrecht joined the research staff at IBM’s Almaden Research Center (San Jose, Calif.). His initial accomplishments there included a widely cited and used frequency-modulation detection method for atomic force microscopes and the development of two technologies that are still widely used throughout the data storage industry: the timing-based servo system for magnetic tape systems and the load/unload inertial latch technology for safely parking/unparking the recording head. As a member of a small team from IBM, Seagate and HP, Albrecht made key contributions to the development of the linear tape open (LTO) standard, which quickly became – and remains -- dominant in the mid-range tape market.

In the late 1990s, Albrecht was a key contributor in the development of the IBM Microdrive, a disk drive smaller than a matchbook that had a 1-inch disk and fit into a Compact Flash II card slot. Albrecht took the initiative in standardizing this new form factor and helped promote its adoption in consumer electronics, enabling the creation of a new class of portable products including Apple’s iPod Mini.

On a two-year assignment in Switzerland in 2002-3, Albrecht contributed to and briefly managed IBM’s Millipede effort to create a solid-state data-storage device using arrays of tiny cantilevers derived from atomic force microscope technology that Albrecht had researched for his Ph.D.

Albrecht’s technical accomplishments have been widely recognized throughout his career. He was a member of the IBM Academy of Technology and has received numerous internal and external awards, including Design News magazine’s “Excellence in Design” award for the IBM Microdrive (2000) and a Hitachi GST Corporate Award for the lifetime achievement of 100 issued U.S. patents (2010). To date, Albrecht has received 129 U.S. patents and was named an HGST Fellow in 2013.


John Contreras

is recognized as an industry technology expert in analog circuits and transmission line design for HDDs. John's leadership in HGST guides our definition and design of the Front-end architecture for HGST’s HDD products: including high speed interconnect design for the HDD suspension, flex interconnect, HDD enclosure RFI/EMI, and preamp architecture. The role John and his Global Team plays has grown significantly in recent years as clock speeds and complex new technologies such as HAMR, MAMR, TDMR, IVC, and ECS are moving through the pipeline from research to staging and product development. John's leadership and innovation have been critical to developing these new technologies for our products. He is manager of the Front-end Systems and RF group and leads our technology design and the WW Front-end team reporting through the Recording Sub-systems Recording Electronics group.

In 1982, John started his career with the IBM Storage Technology Division, San Jose, CA as an Electronics-Packaging Engineer, working on IC packaging and system/cable communications. In 1987, he joined IBM’s Read/Write IC design group and became a technical Lead IC Engineer. In 1996, he joined the Philips Semiconductor Division, Sunnyvale, CA as an Engineering Senior Manager for a Disk Channel IC Design Group. In 1997, he joined the IBM’s Research Center’s Disk Storage Group, as part of the Recording Physics and Instrumentation Group. There, John became a Senior Technical Staff Member. IBM’s Storage Division was then purchased by Hitachi and then became HGST by a purchase of Western Digital. With HGST, he is now Director of Advanced Front-End Systems and RF Group, leading and servicing the World Wide Front-end teams and HDD products (mobile, desktop, and server). Born in Baytown, Texas, John received his B.S. in electrical engineering from the University of Texas, Austin in 1982 and his M.S. degree in mechanical engineering from Stanford University, CA in 1990.

John's recent activities have been focused in on TDMR and HAMR HDD Front-end architectures, electrical interconnect, signal integrity (transfers and EMI related topics), and associated head-slider shunts that support the Front-end technologies (HDI, IVC, and EMC)

John has authored and co-authored 48 U.S patents with an additional 50 U.S. patent applications in progress (98 total) and received the 2nd Runner-up HGST Invention Award in 2013. John has also received technical achievement awards for his contributions in the areas of electronics packaging, write-driver circuits, amplifiers and other circuits related to Read/Write ICs, including an IBM Outstanding Technical Achievement Award for Read/Write IC Designs in 1994, an IBM Research Division Award for Contributions to Advanced Interconnects in 1997 and 6 IBM Team Awards. He has published 9 journal articles and 3 conference papers, and became an IEEE Senior member in 2009. John was named an HGST Fellow in 2014.


Mohammad Mirzamaani

is a leader in developing thin-film media for high-density magnetic recording.

Since 1998, Dr. Mirzamaani has managed the magnetic-media development efforts for IBM, HitachiGST and HGST. In 2004, he led the team of engineers who developed the perpendicular media on a brand new sputtering tool, enabling HGST to be first in the industry to ship products with the high data densities achievable by perpendicular recording.

A native of Esfahan, Iran, Mirzamaani was educated at Sharif University of Technology (B.S., materials science, 1979) and Stevens Institute of Technology (Ph.D. materials science, 1985).

In 1986, Mirzamaani joined IBM’s T.J. Watson Research Center (Yorktown Heights, N.Y.), where he researched the magnetic properties of thin films used in data storage. His 1989 explanation of the origin of magnetic anisotropy in sputtered thin-film media has been widely referenced by university and industry researchers and was a stepping stone to industry’s ability to manufacture magnetically oriented thin-film media. After experimenting with in-situ texturing of glass disk substrates, Mirzamaani in 1990 joined the IBM San Jose team developing the industry’s first magnetic media sputtered onto glass with sputter texture technology. The superior magnetic and physical properties of that media, first mass produced in 1994, put IBM far ahead of its competition.

Mirzamaaani was named an IBM Distinguished Engineer, the engineering equivalent of IBM Fellow, in 1997. He holds 22 patents, has published more than 30 journal articles and has given more than 15 invited talks in technical conferences and universities. He has received three IBM corporate and three IBM outstanding technical achievement awards.


Tetsuo Semba

is a pioneer in designing digital “servo” systems that determine exactly where a disk drive’s recording head must be positioned to accurately read and write data on magnetic hard disks.

Semba’s most recent work at HGST includes a novel high-bandwidth, dual-stage servo controller that reduces the effects of vibrations by controlling a fine-positioning actuator, and a clever new way of reducing variations in data-track spacing that enable higher track density.

A native of Yokohama Japan, Semba was educated at Tokyo Institute of Technology (B.S. electrical engineering, 1977; Ph.D., control engineering, 1998). After working on analog/digital video signal processing at Sony Corp., he joined IBM Japan in 1989 as a researcher and manager of digital servo for magneto-optical disk drives. Semba’s team soon demonstrated the superiority of digital servo over analog servo, and IBM switched to the new technology in its magneto-optical products. In 1993, Semba proposed the digital-servo architecture for IBM’s magneto-optical disk drives and was the technical lead for its implementation.

In recent years, as data densities have increased, accurate head positioning has become more difficult but even more important. To reduce the effects of external vibrations – even playing loud music on a laptop can affect the recording head’s position – Semba helped pioneer the addition of vibration-sensor signals and technologies such as the Rotational Vibration Safeguard ® into servo controls. He also helped introduce adaptive control, which automatically adjusts the sensor’s signal to optimize head-position accuracy, into desktop and mobile disk drives.

Semba became an IBM Distinguished Engineer in 2002 and an HGST Fellow in 2009. He has co-authored more than 50 patents and published more than 15 technical papers in distinguished journals.


Ching Tsang

is an expert in the physics and technology of advanced recording heads and in the science of magnetic recording for disk drive applications.

At HGST, Tsang is currently exploring the magnetic behavior and the design of very small sensors for use in recording heads to support magnetic recording in very high disk drive data densities.

A native of Hong Kong, Tsang was educated at Case Western Reserve University (B.S., electrical engineering, 1972) and Stanford University (M.S., 1974, and Ph.D., 1978, both in electrical engineering). He worked as a postdoctoral fellow at Xerox Palo Alto Research Center before joining IBM in 1978 as a research staff member at its San Jose Research lab.

Tsang’s studies on Barkhausen noise in small magnetoresistive (MR) heads led to key design concepts that enabled the industry’s first MR head for disk drives. The successful deployment of MR head technology enabled disk drives to read much smaller data bits than before and contributed critically to IBM’s huge acceleration in the growth of areal density in hard disk drives, setting world records of 1, 3 and 5 billion bits per square inch from the late 1980s to mid 1990s.

Later, Tsang made key contributions to the exploration and optimization of what would become the next generations of read heads using, successively, current-in-plane giant magnetoresistive sensors and current-out-of-plane tunnel-junction sensors for perpendicular recording applications. These advances led to further areal density records of 12, 230 & 340 billion bits per square inch for disk drive storage.

Tsang has co-authored more than 50 publications on magnetic recording technology and solid-state physics, and holds 30 patents. He was elected Fellow of the IEEE Magnetics Society (in 1996), and served as its Distinguished Lecturer in 1990-1991. Tsang was named an IBM Fellow in 1995.


Roger Wood

is an expert at integrating magnetics, signal-processing and servo-mechanics to improve the performance of magnetic recording devices.

Wood is currently spearheading HGST’s improvements in shingled magnetic recording and helping to apply advanced signal-processing techniques to ensure reliable data recovery under the most extreme conditions of mechanical disturbance to the disk drive.

A native of Bradford, Yorkshire, in the United Kingdom, Wood received a B.S. in Electrical and Electronics Engineering from the University of London in 1972 and a Ph.D. in Electrical Engineering from the University of British Columbia in 1979.

After graduation, Wood began his long career in magnetic recording at Ampex, where he drove the introduction of the industry’s first partial-response, maximum-likelihood read/write channel in a very high data-rate digital instrumentation recorder that was widely used in aerospace industry test flights. In 1986, Wood joined the IBM hard disk-drive division.

Wood was an early proponent of perpendicular recording and in 1999 predicted, to some skepticism, that this technology would surpass longitudinal recording and enable much higher storage densities, up to a limit of about a thousand billion bits per square inch. Wood led IBM’s research efforts and then Hitachi’s advanced development effort for perpendicular recording and the company’s successful transition from longitudinal to perpendicular recording.

Wood’s early predicted limit for conventional perpendicular recording has turned out to be correct. The several new technologies that promise still higher areal densities are all fraught with great technical challenges. In this context, Wood proposed an alternative approach, dubbed two-dimensional magnetic recording (TDMR), based on a combination of partially overlapped shingled magnetic recording (SMR) and two-dimensional read-back using extensive signal processing. Shingled writing is now plan-of-record for next-generation products across the industry. TDMR signal processing has already been incorporated within the read/write electronics used to recover data from corrupted sectors. International conferences now have entire sessions devoted to SMR/TDMR.

In 1996, Wood spent a year on faculty at the National University of Singapore Data Storage Institute. For 18 months in 2003-4, he enjoyed a visiting assignment to the Advanced Technology Division in Odawara, Japan. Wood is a frequent invited speaker at technical conferences and workshops and is active in organizing IEEE Magnetics Society conferences and meetings. He has volunteered time for tutorials on the “Art of Magnetic Recording” to student groups. Wood’s recent external collaborations include work with the Advanced Storage Industry Consortium, Carnegie Mellon University, University of Hawaii, University of Oklahoma and Washington State University.

Wood is a member of the Magnetics Society of Japan, the American Society of Mechanical Engineers and the IEEE Magnetics Society. He was elevated to IEEE Fellow in 2000 and received the prestigious IEEE Magnetics Society Achievement Award in 2009. Wood has authored more than 80 refereed journal papers and holds 18 U.S. patents.


Innovation Equals Patents

Our scientists and engineers are passionate about innovation and technology. The featured video is just one way that HGST celebrates its patent inventors.