Who really created MS-DOS?

Presenter
This is the moment Digital Research—headed by Gary Kildall, the creator of CP/M—dropped the Gap 1. IBM, distinctly unimpressed with its reception, went back to Microsoft. Bill Gates is not the man to give a Gap 2 a second chance. He saw the opportunity of a lifetime.

Bill Gates
“Digital Research didn’t Gap 3 that, and we knew it was essential. If somebody didn’t do it, the project was going to fall Gap 4.”

Microsoft executive
“So we just got carried away and said, ‘Look, we can’t afford to lose the language business!’ That was the Gap 5 thought. We can’t afford to have IBM not go forward. This is the most exciting thing that’s going to happen in PCs!”

Bill Gates
“And we were already out on the Gap 6 because we had licensed them not only BASIC but Fortran, COBOL, Assembler, Typing Tutor and Adventure. Basically, every product the company had, we had committed to do for IBM in a very short time frame.”

Presenter
But there was a problem. IBM needed an operating system fast, and Microsoft didn’t have one. What it did have was a Gap 7 of luck—the ingredient everyone needs to be a billionaire.

Presenter
Unbelievably, the solution was just across town. Paul Allen—Gates’s programming partner since high school—had found another operating system.

Paul Allen
“There was a local company in Seattle called Seattle Computer Products. A guy named Tim Paterson had done an operating system—a very rudimentary operating system that was kind of like CP/M.”

Microsoft representative
“We just told IBM, ‘Look, we’ll get this operating system from the small local company. We’ll take care of it, we’ll Gap 8 it up, and you can still do a PC.’”

Presenter
Tim Paterson’s operating system, which saved the deal with IBM, was, well, adapted from Gary Kildall’s CP/M.

Tim Paterson
“I took a CP/M manual that I’d bought from a retail computer store for $5 in 1976, or something, and used that as the basis for the application programming interface—the API—for my operating system. Using ideas that came from different places, I started in April, and it was about Gap 9-time for four months before I had my first working version.”

Presenter
This is it: the operating system Tim Paterson wrote. He called it QDOS, the “quick and dirty operating system.” Microsoft and IBM called it PC DOS 1.0. Under any name, it looks an awful lot like CP/M. On this computer, I have PC DOS and CP/M-86 running. Frankly, it is very hard to Gap 10 the difference between them: the command structures are the same, and so are the directories. In fact, the only obvious external difference is that the floppy drive is labelled A in PC DOS and C in CP/M. Some difference—and yet one generated billions in revenue, while the other Gap 11.

Presenter
As usual in the PC business, the prize did not go to the inventor but to the exploiter of the invention. In this case, that was not Gary Kildall; it was not even Tim Paterson.

Presenter
There was still one problem. Tim Paterson worked for Seattle Computer Products, or SCP. It still owned the rights to QDOS—rights that Microsoft had to have.

Vern Raburn
“We went back and said to them, ‘Look, we want to buy this thing.’ SCP was like most little companies: it always needed Gap 12, and so that was when it entered the negotiation.”

Paul Allen
“We ended up working out an agreement to buy the operating system for whatever usage we wanted for $50,000.”

Presenter
Let’s pause there to savour a historic moment: “For whatever usage we wanted for $50,000.” It had to be the Gap 13 of the century, if not the millennium. It certainly was. The agreement made Bill Gates and Paul Allen multibillionaires.