There's a new operating system that wants to do away with the old mistakes and cruft in other operating systems. It's called Redox OS and is available on GitHub. It's aimed at creating an alternative OS that is able to run almost all Linux executables with only minimal modifications. It features a pure ecosystem using the Rust programming language which they hope will improve correctness and security over other OSes. They are not afraid to prioritize correctness over compatibility. The philosophy being that "Redox isn't afraid of dropping the bad parts of POSIX while preserving modest Linux API compatibility."
Redox levels harsh criticisms at other OSes, saying "...we will not replicate the mistakes made by others. This is probably the most important tenet of Redox. In the past, bad design choices were made by Linux, Unix, BSD, HURD, and so on. We all make mistakes, that's no secret, but there is no reason to repeat others' mistakes." Not stopping there, the Redox documentation contains blunt critiques of Plan 9, the GPL, and other mainstays.
Redox OS seems to be supported on the i386 and x86_64 platforms. The aims are microkernel design, implementation in Rust language, optional GUI — Orbital, newlib for C programs, MIT license, drivers in userspace, common Unix commands included, and plans for ZFS.
They want to do away with syscalls that stay around forever and drivers for hardware that, for a long time, simply isn't possible to buy any more. They also provide a codebase that doesn't require you to navigate around 25 million lines of code like Linux.
Perhaps the mathematically proven L4 microkernel is something to consider over the monolithic kernel approach where any single driver can wreck the system? One aspect to look out for is if they map the graphic cards into user space.
Most of the Linux APIs were introduced for PowerPC
He might have worked on Macs or PowerQUICC. Not all PPCs were\are at feature parity. Especially when it comes to virtualization* which, similarly to ECC memory, was sometimes offered as a server "premium" feature.
As for seL4, many production L4 family kernels fork off the proven seL4 code base and add patches to address hardware bugs. It's not a "security hole" to have a proven and correct core serve as a main branch that you occasionally fork production branches off and patch for hardware specific issues. It's simply a different development model.
As for RedoxOS, while I personally believe it's a waste of time seriously developing anything new targeting the x86's metal, Rust still needs to prove itself by at least developing it's own toy research operating system. It's the price you pay for calling yourself a systems programming language. D is in the same boat. Go had the sense to avoid it.
*virtualization is the modern term for general memory\device protections, like you said.