Microsoft Word Was Built on Unix Before It Conquered the PC

Microsoft Word's development began long before Windows, and it was initially built for Xenix, Microsoft's version of Unix. In August 1980, Microsoft announced Xenix as a portable Unix system for 16-bit processors, and by 1982, the company was already running several Xenix machines on its internal network. Charles Simonyi joined Microsoft in 1981 after working at Xerox PARC, where he developed Bravo, one of the first WYSIWYG text editors. He brought Richard Brodie with him, and they started working on a new word processor in 1982.

The program was initially called Multi-Tool Word, but it eventually became Microsoft Word. The first version for Xenix was developed in February 1983, followed by a release for MS-DOS later that year. Microsoft aggressively marketed the DOS version, distributing over 450,000 demo disks to PC World subscribers.

The development of Word on Unix makes sense given Microsoft's history at the time. Xenix was a major part of the company's business, and it was even selected by IBM for its PC AT in 1984. However, Windows eventually became the dominant platform, and Word's early years were marked by competition from other word processing software like WordPerfect.