Bill Gates was born in 1955 in Seattle, Washington. He showed an early interest in computers, writing his first program at age 13. He attended Harvard University but dropped out in 1975 to focus on Microsoft, which he co-founded that year with his childhood friend Paul Allen. Microsoft developed the operating system for IBM's first personal computer and signed a pivotal deal that made MS-DOS the dominant operating system. Gates led Microsoft's competitive strategies against rivals and adapted the company to focus on the emerging internet. He is also known for his philanthropic work through the Bill & Melinda Gates Foundation, the largest private foundation in the world.