Microsoft took another step toward releasing a beta version of Longhorn, the next edition of Windows, with the debut Monday of developer tools for the operating system.

The company is providing free downloads of a toolkit that will let developers write applications for Avalon and Indigo, two of the main additions to Windows due with Longhorn. A beta, or test, program for the client version of the Longhorn operating system is due "this summer," according to Ari Bixhorn, lead product manager for Web services strategy at Microsoft. A completed version is expected in the second half of next year.

The kit, called Beta 1 Release Candidate, will also include programming tools for the company's digital ID system called InfoCard, as well as a document printing format code-named Metro.

Microsoft is releasing the kit to allow programmers to become familiar with Longhorn and to encourage the creation of new Windows applications. 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.

As previously reported, InfoCard provides a system for managing an individual's personal information, or identity, when interacting with Web sites. InfoCard uses Web services protocols to record and automatically insert personal information when logging on to a site, said Michael Stephenson, director of product management in Microsoft's Windows Servers organization.

Beta 1 Release Candidate will allow developers to make use of Metro, the document and printing formatting system, which also lets programmers build in so-called "digital rights management" features to restrict usage of documents.

The Avalon presentation system will let developers better manipulate video, Bixhorn said.

The latest update to Indigo includes a feature called "peer channel," which lets two machines running the Indigo software communicate directly in a peer-to-peer fashion.

Microsoft also has enhanced Indigo so that it can work with the company's existing messaging system, called MSMQ, and share transactions with applications written using the COM+ development model, Bixhorn said.

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