Unlessyou’ve been living under a rock for the past couple of days, you’veno doubt heard the news about the impending Longhorn scope cuts. Here are themajor points that I took away from the announcement, along with my thoughts oneach:

WinFS is pretty much gone.

This didn’t raise my eyebrows too much. The problems that WinFS tries tosolve are very hard – and I’m not referring to the technicalchallenges. Sure, coming up with a way of attaching metadata to documents atthe file system level has its fair share of technical hurdles to overcome but Ithink MS is more than up to the task. The real problems are more high-level; thereally hard stuff involves figuring out what all that metadata should looklike. Even then, once the physical representation problem has been solved,there’s still the nasty issue of shared semantics – gettingeveryone to agree on what all this metadata actually means is a reallyhuge task. The vision for WinFS is great, but I don’t think we’llbe getting there anytime soon. Cutting WinFS makes a lot of sense.

Indigo will be available on down-level platforms.

Oooh, shiny! This is nothing new. Indigo has always had plans to make itselfavailable on non-Longhorn systems, so this shouldn’t come as much of a surprise.It’s really a non-announcement and more of reminder of plans that havebeen around for a long time.

Avalon will be available on down-level platforms.

This one did throw me for a loop, because at the PDC Avalon was presented asbeing (in part) a complete reworking of the kernel-mode driver stack. It’salso a new programming model (XAML) and a bunch of new framework classes, butthey all rested on these kernel-mode modifications that would exist only inLonghorn. In fact, I seem to remember someone asking at the PDC if Avalon wouldbe supported on down-level OS’s, with the answer being an emphatic “no”because Avalon relied on Longhorn-specific changes to the core OS in order towork properly. Thus, I’m rather interested to see what Avalon-on-XP willlook like.

If I had to guess, I would imagine that it would be XAML and the frameworkclasses coded to work against the existing Windows display subsystem. What doesthis mean for glitch-free media playback? Where does the vector-based desktopcompositing engine come into play? I have a sneaking suspicion that those twoelements will be noticeably absent from Avalon, because it’s myunderstanding that they took heavy dependencies on the updated kernel. Assumingthat Avalon-on-XP means that no kernel-mode changes will be required to run thesoftware, I doubt that Avalon will be anywhere close to the product that we sawat the PDC. If you take away all the Avalon features that depend on the kernel,what’s left? XAML for WinForms? It’s an interesting programmingmodel, sure, but it’s not central to what I see as the core Avalon story.Hopefully, someone will come forth and convince me that the Avalon situation isnot as dire as it seems to be on first glance.

Longhorn is now a date-driven release.

Perhaps the clearest message conveyed in the announcement is that Microsoft iscommitted to getting Longhorn out by 2006, and is willing to sacrifice featureset in order to do so. This marks a major shift in positioning, as it makesLonghorn more evolutionary then revolutionary. Presumably, this decision wasmade to inject upgrade revenue back into the Windows business, but I’mwondering if it will have the intended effect.

Questions, questions, questions.

If you look at the “three pillars of Longhorn” presented at the PDC(Indigo, Avalon, and WinFS), one is now entirely gone and the other two are notstrictly going to require Longhorn in order to run. Perhaps they weren’tload-bearing pillars after all. It does raise a question, though -- if notIndigo, Avalon, and WinFS, what exactly are the key components of Longhorn?What’s the value proposition? What’s the compelling reason toupgrade? If people were on the fence about making the move to Longhorn beforethis announcement, I don’t see how those people are going to be moreconvinced to upgrade now.

I have a feeling that there are major components of this story that have yet tobe revealed, and that next week will clear things up. What I really want toknow is this: As a customer, why should I upgrade to Longhorn and not justsettle for Avalon/Indigo on XP or 2003?