The improvements to the XGL graphics subsystem that underlies Linux will help it render images faster and improve 3-D graphics and video for users on existing hardware, said Charlie Mancusi-Ungaro, director of marketing for Linux and open-source at Novell. 'This puts Linux at the forefront of where graphical desktop interfaces are going,' he said.

XGL, which stands for X over OpenGL, is a version of the two-decade-old X Window System popular on Unix operating systems. It does not actually provide the desktop interface itself, instead supporting Linux desktop environments such as KDE or GNOME.

At Novell's Web site, users can see videos previewing some of the enhancements provided by XGL. They include transparent application or browser windows so that icons underneath are still visible, windows that can quickly shrink to thumbnail-size while videos continue to play, and -- for power users running many applications -- the ability to open up to four desktops on a 3-D cube interface that users can rotate for program access.

The improvements will be available to Linux users running PCs with 3-D graphics cards and relatively up-to-date hardware, meaning computers that have been bought in the last 18 months or so, said Mancusi-Ungaro.

Jakob Nielsen, a usability expert with Nielsen Norman Group in Fremont, Calif., applauded the transparency and extra desktop features. But he was less impressed with the ability for application windows to be dragged halfway between desktops and viewed in 3-D. He called it 'a great way to show off graphical horsepower but basically useless.'