It seems like you might be referring to "Hitachi GST" or "Hitachi Global Storage Technologies." Hitachi GST was a company that specialized in the design, manufacture, and sale of hard disk drives (HDDs). It was a subsidiary of Hitachi, Ltd. and was a major player in the storage industry.
In 2011, Hitachi GST was acquired by Western Digital (WD), another major player in the storage industry. Following the acquisition, the Hitachi GST brand was gradually phased out, and its products were rebranded under the Western Digital name.
Today, if you're looking for storage solutions, you might find products from Western Digital that were originally developed by Hitachi GST. These products continue to be supported and sold under the Western Digital brand.