Introduction

In January 1987, Digital announced the DECwindows program for workstation software. ^[1] A major goal of the DECwindows program is to provide a consistent, modern user interface for workstation software. This goal was met through development of the XUI (X User Interface) style, which provides a consistent interface style across operating systems, including VMS and UNIX, and across different application programs. This chapter describes the methods that we have used to build consistent interfaces across a large set of software applications, as well as some of the philosophy which underlies these design methods. We believe that these methods can be used to build consistent interfaces in other environments as well.

The DECwindows program is Digital's largest software development project to date. It was initiated at the highest levels of the software engineering organization. Hundreds of people from engineering, marketing, writing, management, sales, and support groups were involved from many different product lines around the world.

The XUI design center was a multiprocessing, networked workstation running the X Window System in international settings. The XUI style was designed for usability on workstations and personal computers with different screen sizes and different input devices, including tablets and mice with 1 or more buttons. Though the design was optimized for a large-screen workstation with a 3-button mouse, the differences in screen size and input device were not as important as the focus on multiprocessed, networked, international systems. Digital's...