From Miguel, looking through his Mono-cle
In the Longhorn world, APIs are no longer your C/C++ grandmother APIs. Every new API introduced for the operating system is built on top of .NET. If you want to take advantage of it, you must write .NET code.
I'm not sure what to think of this yet.
Consider right now CPython, VisualWorks Smalltalk, Haskell (GHC), PLT Scheme, etc. all access dotnet from the "outside looking in".
Consider also that by the time of Longhorn ships (what? 2007?) that interoperability between processes and nodes will be some
N times faster and it is already quite acceptable. Passing messages to Longhorn services will be a common mode of leverage.
It's all about the wire, right? Isn't Longhorn the last gasp of a PC mindset? (BTW, Longhorn can't suck until it's released... reportedly three years from now. This should be plenty of time to reduce suckage.)
Excercise for the reader: Look through the Longhorn material. Make a note of every feature that appears to be caught in the muck of the 1980's PC, or at best the 1980's high-end workstation.
A post-modern Internet OS lives above that muck, diving down as necessary, threading all the pieces together in new ways.