Microsoft was founded to develop and sell BASIC interpreters for the Altair 880. Microsoft rose to dominate the home computer operating system market with MS-DOS in the mid-1980s, followed by the Windows line of operating systems. Its products have all achieved near-ubiquity in the desktop computer market. One commentator notes that Microsoft's original mission was "a computer on every desk and in every home, running Microsoft software." Microsoft possesses footholds in other markets, with assets such as the MSNBC cable television network, the MSN Internet portal, and the Microsoft Encarta multimedia encyclopedia. The company also markets both computer hardware products such as the Microsoft mouse as well as home entertainment products such as the Xbox, Xbox 360, Zune and MSN TV. The company's initial public stock offering (IPO) was in 1986; the ensuing rise of the company's stock price has made four billionaires and an estimated 12,000 millionaires from Microsoft employees.