Paul Allen and Bill Gates founded Microsoft in 1975 to develop software for personal computers. They obtained early success by developing the programming language BASIC for the Altair computer. In 1980, Microsoft moved to Seattle and had $8 million in annual sales. That year, IBM contracted Microsoft to provide the operating system for its first personal computer, and Microsoft acquired the rights to use MS-DOS. The launch of the IBM PC was a huge success that drove further growth for Microsoft.