Microsoft’s original operating system partnership helped popularize IBM’s personal computer.
IBM introduced the IBM PC in 1981 and selected Microsoft’s MS-DOS as an operating system for the machine. Microsoft licensed the system to IBM rather than selling the rights outright, allowing it to license versions to other manufacturers as compatible personal computers spread.
That business arrangement became one of the most important events in Microsoft’s history. IBM supplied the powerful brand and distribution reach, while Microsoft’s software became a standard across a growing ecosystem of PC makers. The expansion of compatible systems helped Microsoft become a dominant software company.
People sometimes assume IBM created the operating system used on the IBM PC. Microsoft developed MS-DOS from 86-DOS, which it acquired and adapted. Microsoft later built Windows as a graphical operating environment, eventually making Windows its best-known product and a foundation of its long-term market value.