A sidebar to the article “A Guide to GUIs,” published in Byte, issue 7/1989, pp. 256.

In 1985, Apple Computer threatened legal action against Digital Research, for its GEM operating environment, and Microsoft, for Windows. It claimed that the products infringed on Apple’s copyright for the visual display of the Macintosh. Both companies signed agreements with Apple to resolve the disputes out of court.

According to the Apple-Microsoft agreement, Apple was willing to tolerate Windows 1.0 and several other programs (such as Excel) as long as Microsoft acknowledged that the displays of those programs were “derivative works of the visual displays generated by Apple’s Lisa and Macintosh graphic user interface programs.”

Then, in March 1988, Apple Computer filed a lawsuit against Microsoft and Hewlett-Packard, claiming that Microsoft Windows 2.03 and Hewlett-Packard’s NewWave (which runs on top of Windows) infringed on the Macintosh’s copyrighted visual display. Although versions 1.0 and 2.0 of Windows are not all that different (version 2.0 has overlapping windows, fatter screen borders, minimum/maximum icons for sizing windows, and mnemonic keyboard selections in menus and dialog boxes), Apple apparently thought that the program was beginning to look too much like the Mac interface.

Microsoft – mindful of its role as a major provider of Mac software – responded that the latest versions of Windows were covered by the 1985 agreement. Hewlett-Packard, which sells very little software for the Mac, went further, filing a countersuit against Apple. According to the Hewlett-Packard suit, the Macintosh copyrights were invalid because Apple didn’t originate its displays but copied them from the work of windowing-interface pioneers such as Xerox’s Smalltalk and Star interfaces. The suit also claimed that Apple had coerced Microsoft into signing the 1985 agreement and was trying to illegally prevent competition in the market for window-and-icon user interfaces.

While many observers thought that Apple could not win the suit, the judge in the case surprised them: In March, he ruled that version 2.03 of Windows was not covered by the 1985 agreement. (A ruling that it was covered would have ended the case in Microsoft’s favor.)

At this writing, the case is headed for trial to determine whether or not Windows and NewWave infringe on Apple’s copyrights. While an out-of-court settlement is again a possibility, some industry observers are concerned that a victory for Apple could spell trouble for other user interfaces and developers of software for those interfaces.