The irony here is that both SerenityOS and Redox are UNIX-like. Of course in their design, they're not purely like most other UNIXen, but they also don't stray away too far.

They offer a POSIX like API on top, which isn't the same thing, as the key APIs, and overall system architecture, are something else.

Also mostly because as it happens in most hobby projects, people keep wanting to replicate GNU due to the existing software, thus keeping the UNIX cycle alive.

The POSIX API comes with a large number of warts and constraints, and requires a great deal of specific machinery to support.

GNU/Hurd it's interesting. It replicates Unix, but it gives far more power to the user.

Interesting are systems like Xerox PARC Workstations (Mesa, Cedar, Smalltalk, Interlisp-D), ETHZ Oberon, Inferno, Apollo/Domain, Tru64, QNX.

QNX it's another Unix in the end any the Photon GUI it's nothing odd to any KDE/Windows 2000 user.

Smalltalk has issues on exporting your software to be run under a standalone way.

On Interlisp, there's Mezzano, a Common Lisp OS, but it needs some tweaks and optimizations.

Oberon UI wise it's the same as Acme under p9/9front/p9port. On Inferno, 9front and Go superseded it in some ideas.

Gilad Bracha is working on that with Newspeak:

https://www.bracha.org/Site/Newspeak.html

> Smalltalk has issues on exporting your software to be run under a standalone way.

What issues?

Do not forget Genode.

Or maybe something like a lisp machine or a smalltalk os?

I would LOVE to build a modern-day operating system using a high-level programming language, even if it were just a pedagogical toy. I love Unix, but it’s not (and shouldn’t be) the final word on OS design.

In the meanwhile, Project Oberon from the late Niklaus Wirth (http://www.projectoberon.net/) is a good example of a pedagogical operating system (and programming language) that isn’t Unix. Project Oberon was heavily influenced by the Cedar and Mesa projects at Xerox PARC.