I think Microsoft would just run chmod 777 and chown root:wheel to the entire filesystem (and any attached disks) and then proceed to run everything as root with a special sandbox for users based on ACLs.
And they would probably use ext2 and add journals to it.
I'm not sure if that's supposed to be funny, but Microsoft's own NTFS bests all of the last generation of filesystems in both features, stability, and performance.
Only recently have unix filesysetms matched and surpassed NTFS (which was built back in the very early 90s!). reisrfs, btrfs, xfs, jfs, zfs, etc. are better than NTFS in some ways, but all the "traditional" unix filesystems do not even come close (ext2/3, hfs, ufs).
Only a little bit. Microsoft has a history of half-assing a great majority of their products. Windows 7 is a great example: it's wonderful compared to everything since Windows 95, but the interface is horribly inconsistent and their are things like UAC and 9 shutdown options that drive me batty. Windows 7 still manages to crash on resume from sleep often enough I refuse to trust it.
> NTFS bests all of the last generation of filesystems in both features,
Definitely no.
> stability,
So close to 100% it's hard to measure any difference. Well... Perhaps it beats BtrFS and other experimental/unfinished products. But, again, it doesn't beat it in features.
> and performance
One thing is sure - NTFS is the fastest OS on Windows.
Correct - mount points are part of 2000 (NTFS 3). I have no doubt NTFS 3 was better than some filesystems released in 2002, provided enough people released filesystems in 2002. It was also probably better than many filesystems still in use on 2002.
Still, NTFS is catching up to other modern features like symlinks...
AFAIK, which is somewhat limited because I am not a Windows user and don't work in a Microsoft shop, NTFS has some cool features, like transactions, I don't think ext3 had. It also has compression (something that makes a lot of sense if you have more processor than disk bandwidth or space) and folder encryption. Oh.. And transactions. Did I miss something?
Define "everything". User-land programs? Not root. Graphics stack? Not root or kernel-space. A quick look at task manager reveals that over 50% of what is running on my computer isn't running as System (root).
And they would probably use ext2 and add journals to it.