Though their rivalry is legend, Microsoft and Apple shared many of their early innovations. In 1981 Apple invited Microsoft to help develop software for Macintosh computers. Some developers were involved in both Microsoft develeopment, and the development of Microsoft applications for Macintosh. The collaboration could be seen in some shared names between the Microsoft and Macintosh systems.
It was through this knowledge sharing that Microsoft was to develop Windows. A system was that used a mouse to drive a graphic interface, displaying text and images on the screen. This differed greatly from the text and keyboard driven MS-DOS system where all text formatting showed on the screen as code and not what actually would be printed. Bill Gates quickly recognized the threat this kind of software might pose for MS-DOS and Microsoft overall. For the unsophisticated user—which was most of the buying public—the graphic imagery of the VisiCorp software would be so much easier to use. Gates announced in an advertising campaign that a new Microsoft operating system was about to be developed that would use a graphic interface. It was to be called "Windows," and would be compatible with all PC software products developed on the MS-DOS system. The announcement was a bluff, in that Microsoft had no such program under development. But as a marketing tactic it was sheer genius as nearly 30 percent of the computer market was using the MS-DOS system and would wait for Windows software rather than change to a new system. Without people willing to change formats, software developers were unwilling to write programs for the VisiCorp system and it lost momentum by early 1985.
In November 1985, Bill Gates and Microsoft launched Windows; nearly two