Although the code for Avalon was previewed at last year's Microsoft Professional Developers' Conference, the company has made a number of major changes.
Significantly, Avalon now installs and runs on Windows XP Service Pack 2 or Windows Server 2003.
Built on top of the .net framework and Microsoft's DirectX 9.0 graphics interface, Avalon aims to provide what Microsoft describes as a unified user interface, by offering a single run time for browser-based applications, forms-based applications, graphics, video, audio, and documents.
To program Avalon, in order to create user interfaces for applications, Microsoft has introduced a markup language called XAML.
By developing the user interface in XAML, Microsoft said users can separate user interface design from the underlying code, enabling developers and designers to work more closely together.
The distribution for this release includes an initial release of the WinFX SDK, which includes documentation, tools, and sample code for building applications to be managed by Avalon.
Microsoft urged users to be cautious with the Avalon code due to its instability. Because this is an interim pre-beta release, expect the documentation to be partially incomplete and some samples to be broken, the company warned.
The release offers basic Visual Studio 2005 tools support for Avalon development, such as updated templates for building applications running both inside and outside of the browser, as well as Avalon user interface components and controls, Microsoft said.
The Avalon controls also support 'ink', which Microsoft said would allow users to develop applications for the TablePC based on Avalon.