Thirty years ago this week, Microsoft set in motion a series of events that would make them the largest name in personal computing and its founders some of the richest men on the planet.

On July 27, 1981, Microsoft finalized a deal to purchase what was then called QDOS (Quick and Dirty Operating System) from Seattle Computer Products. QDOS was authored by Tim Paterson, a programmer for SCP that had written the operating system for use on in-house hardware.

Once purchased by Microsoft, the operating system was renamed MS-DOS (Microsoft Disk Operating System) and was bundled with the IBM PC shortly after.

As the story goes, IBM came to Microsoft in 1981 and requested an operating system for their line of personal computers. IBM's original plan was to use Digital Research's CP/M-86 OS but the two were never able to iron out a deal. Instead, IBM went with Microsoft's 86-DOS and shipped it on IBM computers as PC-DOS. Microsoft paid a total of $75,000 for the eventual goldmine.

Paterson landed a job with Microsoft in May 1981 and eventually worked with the company on and off until 1998. He now runs Paterson Technology, a small company that develops unique hardware and software products near Seattle, Washington.

MS-DOS had a solid run and was updated several times since its debut.Its eventual demise would come in 1994, just a year before Microsoft released Windows 95. Microsoft has released several major revisions since WIndows 95, with current version Windows 7 being the fastest selling operating system in history.