How Windows came to be? - a Windows OS history

Aug 31, 2009

The beginnings

Bill Gates, Paul Allen, 1975 The term “Micro-soft” was first used by Bill Gates in a letter to Paul Allen in 1975, and a year later the trademark “Microsoft” was registered. Microsoft's destiny was determined when they landed the world's most famous business deal with IBM - to provide them with an operational system. This ties up, however, with the world's worst business deal which was made by Gary Kildall's wife, Dorothy, meaning not to sign a license agreement with IBM for their own OS, the PC/M.

Everything started in 1980 when IBM approached Bill Gates and his new company, Microsoft, on a meeting about home computers and Microsoft products. Gates came up with a few ideas about how a personal computer should act, and among them was the one to incorporate Basic into the ROM chip. This was actually not a new idea, since 1974 when Bill Gates and colleague Paul Allen created a Basic code for the first microcomputer kit, the Altair 8800.

As for operating systems, because Microsoft had never written one before, Gates suggested that IBM should approach an OS called the Control Program for Microcomputers, or CP/M, from Digital Research owned by the Kildalls. Upon coming to an agreement, Gary sent his wife Dorothy, as he always did when it came down to business bargains, but this proved to be quite uninspired, since Dorothy made the worst business deal in history, refusing to sign the IBM non-disclosure agreement.  Tough luck for them, because IBM went back to Gates and gave him the contract for providing an operating system that would pair up with every personal computer that IBM would create. Gates did not let the opportunity to slip away so he went to search for an already existing operating system.

He found it at Seattle Computer Products and it was called the “Quick and Dirty Operating System” written by Tim Paterson. Paterson designed it for their own prototype Intel 8086 based computer and, ironically enough, it was based on Kildall's CP/M. Paterson bought a CP/M manual and used it as a basis to write his own operating system in just six weeks. But because of Paterson's keen talent, QDOS was different enough from the PC/M to be considered legal.

Altair 8800 Bill Gates stepped in and bought the license rights for QDOS for $50,000, making sure, of course, that Seattle Computer products did not have a clue about the IBM deal. He then renamed the QDOS in MS-DOS, Micro-soft – Disk Operating System.

Afterwards, Gates approached IBM and convinced them that Microsoft should keep the license rights to MS-DOS, marketing it as a separate product from the IBM Personal Computer project. In this way, Gates managed to make a fortune out of licensing MS-DOS for IBM. In 1981, Tim Paterson left Seattle Computer Products and found employment at Microsoft, the same year when Microsoft started working on the first Windows version.

Other articles in this series:

1. The beginnings
2. First steps in operating systems
3. Windows 1.0
4. Windows 2.0
5. Windows 3.0
6. Windows 95
7. Windows 98
8. Windows Me
9. Windows 2000
10. Windows XP
11. Windows Vista
12. Windows 7
13. Windows 8