The Free On-line Dictionary of Computing (30 December 2018):

VxWorks

    A real-time multitasking operating
   system from Wind River Systems.  Originally it used the
   VRTX kernel but this has been replaced by Wind River's own
   "Wind kernel 2.4".

   Before version 5.3 VxWorks included a software development
   environment but this is now called "Tornado".

   (1996-11-29)