I have vivid memories of working on Longhorn as an intern. It was an incredibly ambitious project - rewrite of the "filesystem" (really, a relational object store!), driver framework and display stack to name a few. The project failed the same exact way many projects fail - they are too ambitious and not well-scoped. The demo Hillel showed, IIRC, was complete vaporware.
WinFS wasn't a filesystem, but implemented upon NTFS as filesystem filter driver and dotNet based service, the files were stored in a hidden directory (SQL Server Compact and raw files with generated filenames in sub folders). The dotNet service was just very slow.
The original vision of "information at your fingertip" was behind the Cairo project. And Cairo had an object stored in the NTFS filesystem driver. WinNT4 and 2000 got several of the Cairo inovations. Well, some hidden APIs were still left in (at least in WinXP era).
I think Longhorn was in large where we have now finally got with Windows 8 and onwards (not 7). An OS with core apps written in .NET, an object oriented data management system in Powershell. PS unites e.g Windows Registry and common files under the same umbrella. Windows 10 also completes the vision of a shared OS for all appliances.
Unfprtunately I think it took MS too long to get here. Other vendors got to the home appliances part before them, which is mind boggling given the traction MS had once upon a time.
And from what I understand ReFS is also implemented on top of NTFS, but this time it's real, shipped code and meant to provide some of the features found in ZFS to Windows users.
Can you point me to a source? I've read conflicting articles on it and frankly I found it odd that they supposedly would layer ZFS-like features on top of NTFS.
At least I read it as »We took the API and a bunch of support infrastructure for that API and simply changed the storage engine on disk completely underneath that.«
