HGST (formerly Hitachi Global Storage Technologies) is a wholly owned subsidiary of Western Digital that sells hard disk drives, solid-state drives, and external storage products and services.
Hitachi Global Storage Technologies was founded in 2003 as a merger of the hard disk drive businesses of IBM and Hitachi. Hitachi paid IBM US$2.05 billion for its HDD business.
On March 8, 2012, Western Digital (WD) acquired Hitachi Global Storage Technologies for $3.9 billion in cash and 25 million shares of WD common stock valued at approximately $0.9 billion. The deal resulted in Hitachi, Ltd. owning approximately 10 percent of WD shares outstanding, and reserving the right to designate two individuals to the board of directors of WD. It was agreed that WD would operate with WD Technologies and HGST as wholly owned subsidiaries and they would compete in the marketplace with separate brands and product lines.
To address the requirements of regulatory agencies, in May 2012 WD divested to Toshiba assets that enabled Toshiba to manufacture and sell 3.5-inch hard drives for the desktop and consumer electronics markets.
- Hitachi Global Storage Technologies Japan, Ltd.: Japanese branch of Hitachi Global Storage Technologies, Inc.
- G-Technology/Fabrik, Inc.: A storage solution company. On February 23, 2009, Hitachi Global Storage Technologies announced it has agreed to acquire Fabrik, Inc. On 2009-04-06, Hitachi Global Storage Technologies announced it has completed the acquisition of privately held Fabrik, Inc. Fabrik’s business would form the core of Hitachi GST's new Branded Business division. Following the acquisition, the subsidiary was branded 'G-Technology by Hitachi'.
Hard Drives and Solid State Drives 
- Ultrastar – Enterprise-class line of 3.5-inch and 2.5-inch HDDs with SCSI, Fibre Channel, SAS, and SATA interfaces; and a line of 3.5-inch and 2.5-inch Fiber Channel and SAS SSDs.
- Deskstar – Desktop-class line in 3.5-inch form factor with PATA and SATA interfaces.
- Travelstar – Mobile-class line in 2.5-inch form factor with PATA and SATA interfaces.
- Endurastar – Ruggedized line in 2.5-inch form factor with PATA interface, primarily for automotive applications.
- Cinemastar – 3.5-inch and 2.5-inch form factors, optimized for consumer electronics applications requiring quiet operation and streaming support.
External Storage Solutions 
- LifeStudio - The first external hard drives that combine photo organization software, a 3D Wall for displaying content, a connected USB Flash key, and both local and cloud storage , 
- G-Technology - G-Technology drives are engineered to meet the needs of the content creation and Apple Mac communities, including heavy users of multimedia content, Final Cut Pro digital audio/video specialists and other pre/post production professionals. From portable drives to rack-mount arrays, G-Technology’s USB, FireWire, eSATA, SAS and Fibre Channel storage solutions support virtually all levels of Audio/Video production.
See also 
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