Some extremely different systems: Fuchsia, Cisco IOS, Garmin OS, QNX, RISC OS, Haiku, z/OS and the entire family, Blackberry 10.

There are probably more there. I recognize about half of those names only.

Are you really saying that it's normal to be harder to port some software into Windows than into z/OS?

> Are you really saying that it's normal to be harder to port some software into Windows than into z/OS?

No, I'm saying that from 89 OSes mentioned on that picture, a lot of them are better at being *nix because they are *nix.

But answering your question, sure! The only good thing in POSIX is that you have easy access to a lot of *nix software. Other than that, POSIX is a spectacularly bad API.

Windows doesn't really care about running *nix software natively, because most of Windows userbase just want and use different things. Therefore, why invest into a bad API? For those wanting to use *nix software on Windows, there is Cygwin or WSL anyway.

4? Chrome OS, Android, Qubes OS, Linux