The concept of Teradata grew from research at California Institute of Technology and from the discussions of Citibank's advanced technology group in the 1970s. In 1979, the company was incorporated in Brentwood, California by Jack E. Shemer, Philip M. Neches, Walter E. Muir, Jerold R. Modes, William P. Worth, Carroll Reed and David Hartke. Teradata released its DBC/1012 specialized database computer in 1984. In 1990, the company acquired Sharebase, originally named Britton Lee. In September 1991, AT&T Corporation acquired NCR Corporation, which announced the acquisition of Teradata for about $250 million in December. Teradata built the first system, over 1 terabyte, for Wal-Mart in 1992.