Re: Impossible!
Hmm, I couldn't find that quote in the page you linked to. In fact, there was only one mention of the word 'codebase' and that was (ironically) in the phrase 'A big complex codebase can have many lurking holes that will take many years to uncover.'
I'm going to have to agree with the previous poster about you not understanding what quote marks are for (as applied to Google search terms).
Look for "the entire codebase of Windows has been rewritten from the ground up" and you will only find reference to your post (plus possibly this one now that I've repeated it).
The closest I could find (within the edit window of this post) is this:
"“We have re-imagined Windows from the ground up.” ~ Steve Ballmer"
from here
https://techpinions.com/8-questions-for-windows-8/10010
Biting the hand that feeds IT
