Bill Gates and Paul Allen were computer-obsessed as kids. They started Microsoft after Gates dropped out of Harvard and he and Allen proposed a programming language to a firm constructing small personal computers to hobbyists. Basic programming sufficed in the 1970s, but developments in the early 1980s brought demands for sophisticated operating systems. A lucrative contract with multinational giant IBM would enable Bill and Paul to create the Microsoft Disk Operating System; the precursor to the first Windows system which appeared in 1985. These early achievements pale in comparison to that of Windows 95, which came in CD format and featured 32 bit graphics, start menu, taskbar and an internet browser. Its technological prowess and user-friendly interface meant that 80% of the world's computers had Windows OS in the late 1990s. In the 21st Century, Microsoft introduced the XBOX, its own mobile OS and the two in one tablet/laptop, the Microsoft Surface. The founders too decided diversify their portfolios, and are also known for their huge philanthropic endeavours as well as investments in science, technology and education worldwide.