The story goes that when the IBM suits arrived at IGR (it was 'Intergalactic Digital Research', later to become just 'Digital Research'

Gary Kildall was out flying his plane, and his wife, Dorothy, refused to sign the non-disclosure agreement with IBM.
When the IBM'ers returned to Microsoft, still OS-less, Gates then promised to deliver them an OS. Gates then paid Tim Paterson of Seattle Computer Products $50,000 for their QDOS (Quick and Dirty Operating System) that MS then hacked into DOS.
I've often wondered how Gates must have felt after he'd sent the IBM people to IGR, realising perhaps too late that here was the ultimate pot of gold slipping through his fingers. Had Kildall had the business drive and acumen of Gates, the world would be running DR Windows instead of MS Windows. But Gates had the luck that few businesses get - a second bite at the cherry, and he wasn't letting it slip again.
Mind you, Gates had more than luck. His mother, Mary, sat on the national board of United Way, along with IBM chairman John Opel. They became friends, Opel was impressed that Lowe was talking to MS, and that clinched the deal for Gates.