Weby--No. You write: "Note that the author of the powerpoint see xbox as a closed propriatary system"
Oh come on. He just threw a bunch of systems randomly under different categories under the rubric he calls "Trusted Hardware". He then appends a Question Mark to each system in the Proprietary Category to make sure the reader understands that he is not making any specific statements regarding the random systems he randomly gathered. Including one system called an "Applei Thingy". By the way, the XBOX he refers to as XBOX-3 doesn't even exist.
You really believe there is the possibility that XENON with "custom security features built directly into the silicon to prevent piracy and hacking is not going to be compatible with LONGHORN?
"The Xenon CPU was designed by IBM in close consultation with the Xbox team, leading to a number of revolutionary additions, including a dot product instruction for extremely fast vector math and custom security features built directly into the silicon to prevent piracy and hacking."