Essence: Desktop operating system built from scratch
So first off: Very cool. <i>Amazingly</i> polished, and self-hosting! Especially since it looks to be an actually-independent project with POSIX as an <i>optional</i> compat layer.<p>I feel like the features that are unique are mostly in 3 groups:<p>1. Features that shouldn't be unique to this system. Tabbed windows have <i>occasionally</i> happened on other systems, and probably should become more common, and there's no reason it shouldn't work on other systems. I hope this inspires other people to copy;)<p>2. Features that only work if you have really tight integration or different primitives than most OSs are using. Programs updating file name when you rename from the file manager, or the file manager showing when files are open... <i>might</i> be possible to graft on to other systems, but it'd be a right pain. Even systems like MacOS are going to struggle - the whole OS is under one company that <i>could</i> do cross-functional stuff like that, but any time it touches applications you need external developers to support it and that may or may not work out.<p>3. Features that are possible, but nobody else does it because it's impractical - possibly only impractical from their starting points, though.  Showing total size of subdirectories is expensive on ex. Linux because you have to walk every file recursively. I don't know if they're just eating the cost because they haven't hit a case where it matters, or if their system actually makes it cheap (I could easily imagine a filesystem that moved the calculation cost up front).