How far can software developers working on a user interface go towards creating a Window / Icon / Mouse / Pointer or WIMP display without infringing Apple Computer’s copyright in the Macintosh user interface? For years the issue has remained largely unresolved, though most companies have now learned to restrain themselves from describing products as having a Mac-like interface, through fear of incurring Apple’s wrath. Last week the issue came out into the open, when Apple launched suits against Hewlett-Packard Co and Microsoft Corp (CI No 892), in a move that could pose a threat to rapid take-up of IBM and Microsoft’s Presentation Manager user interface for OS/2 – a product that was beginning to be widely touted as a suitable model for the long sought-for Unix interface standard, with the X/Open Group said to be carrying out evaluation. In the Unix world, the move looks set to delay the announcement of the user interface component of the Sun/AT&T binary interface development, which was expected to be revealed shortly. Sun spokesman Bill Woo called the move clearly unfortunate for the industry; it will be difficult to come up with an interface that doesn’t infringe the copyright. He said that AT&T and Sun were continuing to work and talk to a lot of parties about the interface, and hinted that further announcements were unlikely before the situation was resolved although something should shake out within the next three months. AT&T said it would not comment on future announcements, though a separate AT&T source claimed that an interface announcement had originally been scheduled for the next few weeks. Apple appears unlikely to agree to a monetary settlement. In a development in the suit, Microsoft announced Monday that Apple had agreed to a Microsoft proposal to make public the 1985 licence agreement that covers the use of visual displays. In the preamble, the agreement says that Microsoft and Apple have a long history of co-operation and trust and wish to maintain that mutually beneficial relationship. However, a dispute has arisen concerning the ownership of and possible copyright infringement as to certain visual displays generated by several Microsoft software products – Windows Version 1.0, Multiplan, Chart, File, Excel and Word for the Mac. Under the agreement, Microsoft acknowledged that the visual displays in the programs were derivative of the displays generated by Apple’s Lisa and Macintosh graphic user interface programs. In return, Apple granted Microsoft a non-exclusive, worldwide, royalty-free, perpetual, non-transferrable licence to use these derivative works in present and future software programs and to licence them to and through third parties for use in their software programs. Apple also waived other copyright, patent, trade secret or other claim or right it may have as to Microsoft Windows Version 1.0. Microsoft in return granted Apple a non-exclusive, worldwide, royalty-free, perpetual, nontransferrable licence to use any new visual displays created by Microsoft during a period of five years from the date of the agreement as part of Microsoft Windows in software programs. The key issue appears to be whether Windows 2.03 is simply an enhancement to 1.0, in which case it appears to be protected under the new visual displays clauses, or whether it is effectively a new program and therefore perhaps not covered by the agreement – and that’s the judgement of Solomon that the court will have to make.