The Need For Another Window System

These days, most computer systems are supplied with at least one window system. However, before the advent of X, each computer vendor provided its own opinion of what constitutes a good user interface. For example, Sun workstations were supplied Sun's proprietary window system, called Sunview. Hewlett Packard supplied a proprietary window system called HP windows. The same trend can be seen with Silicon Graphics, Apollo and most other workstations. For PC users, there is Microsoft Windows, and the Apple Macintosh has its own proprietary window system.

One disadvantage of the window systems mentioned so far is that they are all different from each other, from both a user's and a programmer's viewpoint. A dedicated Macintosh user may find using Microsoft Windows on a PC somewhat disconcerting. A programmer may have stronger feelings! Another disadvantage is that an application program written for one of these window systems is restricted to running on that kind of system only and on a single computer.