Microsoft has released something that a lot of developers have been waiting for: the Longhorn SDK. Included are the first widely published tools for building Longhorn applications. Beta 1 of the desktop version of Longhorn is still due ‘this summer,’ but the new OS won’t mean much if there’s no software to run on it. That’s what makes this release so important.

The Longhorn SDK includes all the major components that will be in the final release of the operating system -

Programs written for Indigo, a Web services and communication architecture, and Avalon, a new graphics and presentation engine, will also be able to run on two common current versions of Windows, Windows XP and Windows Server 2003. Avalon and Indigo will be part of Longhorn but also made available separately, when Longhorn ships, for Windows XP and Windows Server 2003. Part of Metro may also be available for versions of Windows other than Longhorn.