Windows is a graphical user interface (GUI), sometimes also called a ”visual interface“ or ”graphical windowing environment.“ The concepts behind this type of user interface date from the mid-1970s, with the pioneering work done at the Xerox Palo Alto Research Center (PARC) for machines such as the Alto and the Star and for environments such as Smalltalk.
The work done at Xerox PARC was brought into the mainstream and popularized by Apple Computer, Inc., first in the ill-fated Lisa and then a year later in the much more successful Macintosh, introduced in January 1984. The Apple Macintosh remains a significant challenger to IBM's dominance in the personal-computer business market. It is not so much the hardware of the Macintosh but its operating system that makes the machine so appealing to users. The Mac is simply easier to use and learn than an IBM PC running MS-DOS.
Since the introduction of the Macintosh, graphical user interfaces have bloomed like wildflowers throughout the personal-computer industry and the not-so-personal computer industry as well. For IBM-compatibles running MS-DOS, there is Windows. For IBM-compatibles running OS/2, there is the Presentation Manager. For the Commodore Amiga, there is Intuition. For the Atari, there is GEM. For machines running UNIX, there is the X-Window system. For Sun Microsystems workstations, there is NeWS. For the NeXT, there is NextStep.
It is obvious that the graphical user interface is now (in the words of Microsoft's Charles Simonyi) the single most important ”grand consensus“ of the personal-computer industry. Although the various graphical environments differ in details, they have similar characteristics.