The whole L4 family and MACH or Hurd ;) and maybe have a look at Genode where you can have ~7 kernels atm: nova okl4_x86 foc fiasco pistachio linux sel4

The whole L4 family and MACH or Hurd ;) and maybe have a look at Genode where you can have ~7 kernels atm: nova okl4_x86 foc fiasco pistachio linux sel4 https://genode.org/documentation/components https://genode.org/documentation/components Also QNX and RTEMS need's to be mentioned here. And Helios/Ares-os: https://sr.ht/~sircmpwn/helios/ https://sr.ht/~sircmpwn/helios/