Nixdorf Computer AG was a computer company founded by Heinz Nixdorf in 1952. Headquartered in Paderborn, Germany, it became the fourth largest computer company in Europe, and a worldwide specialist in banking and point-of-sale systems. Its main products were the 886x family of BNC, or Branch Network Computers, which ran a proprietary operating system (called DIPOS), the 8870 mini computer for business which ran a comprehensive business application software suite (called COMET written in a dialect of BASIC) and the 8812 Electronic Point of Sale (EPOS) terminal; over 200,000 of these systems were sold worldwide in the late 1970s and 1980s. Other products included private branch exchanges as well as software products, of which TWAICE, an Expert System Shell, at that time was amongst the most visionary. In 1990, Nixdorf was acquired by Siemens and renamed Siemens Nixdorf Informationssysteme. After the splitoff of Siemens Nixdorf's Personal Computer products to Fujitsu Siemens Computers, the present day company Wincor Nixdorf is its closest incarnation.