ll Programming Language Environment} where APPLE was the operating system used for WPC). XINA is uniqu... eaded operating system originally created by Douglas Comer and documented in a very well known two vol... didn't care much for that. Comer's XINU license was much more friendly to the lawyers; namely, we cou... o a real-time system, and in the end proved to be as easy as Linux or BSD to work with in an embedded