In early 1984, Apple Computer introduced the Macintosh. This machine was designed and put into developed by Apple after a visit to the Xerox Palo Alto Research Center (PARC). At PARC, Steves Jobs and Wozniak had seen a demonstration of the Alto workstation, the first true GUI computer that used a mouse to navigate on-screen windows. Bill Gates of Microsoft had also seen a demo of the Alto, but he and his company were somewhat slower to create a product based upon the concepts.
The introduction of the Macintosh started to shift the paradigm of operating systems away from the earlier command driven examples (CP/M, DOS, etc.) The new Graphical User Interface would eventually redefine the personal computer industry.
Microsoft would release the first version of Windows about a year after the Mac was introduced.
After being trumped by Compaq, IBM introduced a computer based on the Intel 80286 16 bit microprocessor, the IBM PC AT.