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