title: Are There any Open Source Real Time Operating Systems for x86?
body: <p>Are there any open source real time operating systems out there?  I've heard of real-time Linux, but most implementations seem to really be a proprietary RTOS (that you have to pay for) that run Linux as a process -- much the same way Ardence's RTX real-time system works for Windows.</p>
  
  <p>EDIT: I should clarify that I'm looking for RTOS to work with multi-core x86-family CPUs.  </p>