Wow. You hear alot of rumours about Lisp-based operating systems but you rarely come across a project that appears active. Movitz looks like a promising active LispOS project! It’s goal is to provide a development platform to run CL-based kernels on x86 PCs “on the metal”. I guess these restrictions make it doable. I’d prefer to see CL or Scheme combined with Linux or FreeBSD kernel so that you could still have a viable usable system and also experiement with OS ideas using lisp. In this respect, Schemix looks interesting. It’s a Scheme interpreter (based on TinyScheme) patched into the Linux kernel. I haven’t looked at it closely but imagine that it’s interpreted nature means that it is probably only useful for early prototyping of ideas and certainly for exploring and learning about the kernel.