Make mention of Longhorn and Microsoft may still reflexively hold its cards close to its chest. But as the launch date draws closer, the company has begun to show its hand. Nearly three months after granting MSDN subscribers a November sneak preview, Microsoft has made public a consumer technical preview of its Avalon graphics subsystem.

Avalon is a unified presentation subsystem for Windows that is scheduled for release sometime in 2006. Although originally intended to be exclusive to Longhorn, Avalon will now ship as an add-on to Windows XP, Windows Server 2003 and other future Windows releases.

According to Microsoft, Avalon unifies how Windows "creates, displays, manipulates documents, media, and user interfaces."

Like Longhorn's WinFS storage platform, the first iteration of Avalon will be scaled back from what was originally promised due to its complexity.

Avalon contains a new markup language based on XML -- dubbed "XAML" -- that can be used to create Avalon interfaces. Microsoft is rumored to be developing a front-end programming tool that automates XAML application building code-named Sparkle. Sparkle is a potential competitor to Macromedia's Flash because Microsoft is bringing together its application and development model.

The Avalon Consumer Technical Preview is available for public download via FileForum.