Microsoft Abandoned Its Partnership with IBM for the Rising Star of Windows

Microsoft's operating system strategy in the late 1980s was centered around OS/2, a joint project with IBM to replace DOS. However, this partnership ultimately failed due to the growing success of Windows. In fact, by 1990, US and Canadian sales of Windows applications rose 157 percent, according to Software Publishers Association figures cited by Microsoft.

Windows 3.0 was released in May 1990 with better memory management, a cleaner interface, and room for serious graphical software. This made Windows look like a genuine mass-market platform rather than an optional graphical layer most PC owners could skip.

The growing Windows software ecosystem gave Microsoft another reason to change course. Meanwhile, Dave Cutler was building the escape hatch, leading development of a new portable operating system at Microsoft in 1988, which would eventually matter far more than either company could have predicted when the IBM partnership began.