As for Longhorn Beta 1, that milestone release is still on track for "this summer" though Microsoft this week officially missed their original internal release date of June 30. My sources say that Microsoft now plans to ship Longhorn Beta 1 in late July. The Beta 2 release is still scheduled for November. Internally, most Longhorn product groups have already shipped their Beta 1 code to the Windows team and Microsoft is now prepping various 5200-series builds (post-Beta 1) for internal rollout and testing. My sources describe Longhorn Beta 1 as being one of the most stable Beta 1 OS releases in Microsoft history, though it will lack most of the UI niceties the company plans for future releases. Beta 2, I’m told, is going to be "incredible" and "far more impressive than people now realize." We shall see.
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The Longhorn Team is definitely on a role. 5200 series is very far in the build process (farther than I had expected), so its possible that the OS will make it into the 6000 series by RTM.