Seagate Technology PLC (commonly referred to as Seagate) is an American data storage company. It was incorporated in 1978 as Shugart Technology. Since 2010, the company is incorporated in Dublin, Ireland, with operational headquarters in Cupertino, California, United States. Seagate developed the first 5.25-inch hard disk drive (HDD), the 5-megabyte ST-506, in 1980.