>>11493223 (pb)
What's the story behind the guy Bill Gates bought DOS from?
When IBM couldn't or wouldn't make a deal with Kildall, Microsoft bought what became MS DOS from Seattle Computer Products for $50,000 and licensed it to IBM. It was written by Tim Paterson, who mimicked CP/M's application programming interface. How much of Kildall's intellectual property he appropriated is a matter of some dispute.
https://www.quora.com/Whats-the-story-behind-the-guy-Bill-Gates-bought-DOS-from