Avalon, WinFS decoupled for Windows Shorthorn

Cue 'out-of-band add-on packs'

As we suggested on Friday, two mainstays of Windows Longhorn will be 'decoupled' from the 2006 release, with Microsoft dropping the WinFS storage and query system. Originally intended to be a full-blown replacement for the NTFS file system that put a database at the heart of Windows, WinFS will now be available as an add-on no sooner than 2007 for Longhorn, XP and Windows 2003. Or to be more precise - and here is another new piece of jargon for Redmond watchers - WinFS will be released as an "out-of-band add-on pack". Got that?

A cut-down version of Avalon, minus the compositor and the new device driver model will be backported to Windows XP too. Microsoft had already pledged to backport the next generation of middleware APIs, code named Indigo, to XP. All of which has left developers questioning the necessity of a 'big bang'.

"If WinFX (including Avalon and Indigo) are going to be available for WinXP and Win2003.  What is going to be the point of Longhorn?" wrote one developer on Microsoft's bulletin boards.

Longhorn-unique Avalon features that may survive - and it's a decision that has yet to be made - include a desktop manager (DWM), compositor (DCE) and new driver model (LDDM). As we wrote last week, a new resolution-independent display model is a necessity given the increasing density of LCD screens.

As one correspondent points out, decoupling might actually have the effect of making Avalon more attractive than before, as the potential client base will include XP users who've installed the er, out-of-band add-on pack. However not all Avalon Longhorn features will work on XP, such as the 3D effects touted in Glass. And ensuring that the two rendering engines - Longhorn and Avalon-lite - sing the same song is going to be a challenge for Microsoft developers.

We'll be gathering more reaction, and comment from Microsoft itself, later today. ®

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