These are drivers provided by Microsoft for the Microsoft BusPort, serial, and PS/2 mice. Introduced in 1983, The Microsoft Mouse is historically important as it was one of Microsoft's earliest hardware products (The other being an Apple II Z-80 CP/M card). The first Mouse for the IBM PC was actually from Mouse Systems, not Microsoft. However, most clone mice emulated Microsoft's serial protocol and DOS driver software interface. The first Microsoft application designed to make full use of the mouse was Microsoft Word for DOS, and they hyped a product called "Microsoft Windows" (not released until several years later) that was to compete against the upcoming Apple Macintosh and the Mouse Systems based Viscorp Visi On.