> Did you even read the first few paragraphs of the page?
I did. I also worked at Microsoft during the years in question.
edit in response to your edit: The project was restarted. Longhorn and its three pillars were essentially thrown out. Windows Vista was rebuilt from scratch on top of Windows Server 2003. I assume they chose to keep the same codename so as to reduce confusion. But that doesn't mean it was the same OS.
I did. I also worked at Microsoft during the years in question.
edit in response to your edit: The project was restarted. Longhorn and its three pillars were essentially thrown out. Windows Vista was rebuilt from scratch on top of Windows Server 2003. I assume they chose to keep the same codename so as to reduce confusion. But that doesn't mean it was the same OS.
Hopefully this Wikipedia article answers the rest of your questions: https://en.wikipedia.org/wiki/Development_of_Windows_Vista#M...
edit 2: here's another article:
http://www.vanityfair.com/news/business/2012/08/microsoft-lo...