Sun Microsystems Inc has been driven by customer demand to provide an implementation of X Window, conceding that an emulation of X under its NeWS Network-extensible Window System is not enough. The company will be using X.11, which is expected to be shipped some time this summer. Previously Sun had supported an X.10 emulation which is significantly different from X.11 in that X.10 does not support alternative windowing styles where X.11 does; X.11 also enables manufacturers to add commands to the standard 100 most commonly desired for windowing systems using exposed data structures. X.11 differs from NeWS in that the Sun product is based on the Postscript language and in theory an unlimited number of commands can be developed by the applications builder. Use of Postscript, which is device- and resolution-independent, also saves the programmer the need to change the application when it ported to a different machine. Sun concedes that there probably will not be one windowing system standard but believes that windowing systems will follow the example of operating systems so that a couple will emerge as the leaders, as MS-DOS and Unix have done in the operating systems fray, and then even these few will converge so that they can be used together – as MS-DOS has acquired more Unix-like features and Unix has become easier to use, and both now co-exist in new implementations. Sun intends that applications builders should not suffer through using Sun’s windowing systems, as those using the current version of NeWS will be able to port to the merged version, and developers writing for X.11 will also be kept happy. The losers in all this will be applications developers using the X.10 version as shifting their applications will entail extensive re-writes, says Sun, adding that there is currently no solution for them. The architectures of both X and NeWS, despite the differences mentioned, are very similar in that both are server-based and allow window applications to run across a network so that each task can be allocated to the machine that will most efficiently handle the function. Sun has also announced additional NeWS licencees including Alliant Computer Systems, Data General, EDS, Intel, Interactive Systems, Toshiba and Unicad. Sun’s move to merge the two windowing systems has brought a favourable reaction from a number of companies including Whitechapel Workstations in this country which says that it will be following the same path; Visual Engineering considers X to be the de facto Unix windowing standard and is pleased that it can support standards but also make use of the useful new features of NeWS. A happy Massachusetts Institute of Technology adds that Sun technical staff have helped in specifying the X.11 release.