Teradata
Teradata is a Database management system created by NCR Corporation. It consists of both custom hardware and custom software. The main point with the Teradata DBMS is that it can handle more than 1 Terabyte of data, which is a reason to why it is used a lot in very large scale data warehousing applications.
Teradata runs its own operating system, NCR UNIX SVR4 MP-RAS, a variant of System V UNIX from AT&T.
Teradata DBMS often stand by themselves and are used through ODBC by applications typically running on a different operating system such as Microsoft Windows or other flavors of UNIX.
The first and foremost customer of this DBMS is Wal-Mart, who run their central inventory and other financial systems on Teradata.
The main competitors are other high-end vendors such as IBM and Oracle.