@inthehands Did you know the original Mach, the experimental microkernel that gradually turned into Mac OS X, originally had a feature where userland program 1 could launch userland program 2 in a special way, and then from program 2's perspective program 1 was the kernel. Program 2 would think it's sending syscalls to the kernel but the syscalls are all going to program 1 and program 1 is allowed to freely decide whether to forward them on to the real kernel or just likeā€¦ lie